Chapter 5

Pharmacopoeia

Pharmacopoeia

Pharmacopoeia

Users are advised to always check local guidelines and formularies and to consult the BNF when prescribing drugs.

ACEi Angiotensin-converting enzyme inhibitor. Dose See Tables 5.1 and 5.2 on how to commence a patient on an ACEi Indications Heart failure, hypertension, diabetic nephropathy, prophylaxis of cardiovascular events Caution Pregnancy and breastfeeding, patients already taking diuretics, renal artery stenosis/renal impairment, aortic stenosis, hyperkalaemia, known allergy to ACEi. May not be effective in African-Caribbean patients SE Postural hypotension, renal impairment and hyperkalaemia, dry cough, taste disturbance, urticaria and angio-oedema. If cough is problematic for the patient, consider AT II receptor antagonist ( p. 190), or other antihypertensive agent.

Table 5.1 ACEi

Enalapril	Dose Initially 5mg/24h PO up to max 40mg/24h PO
Fosinopril	Dose Initially 10mg/24h PO up to max 40mg/24h PO
Lisinopril	Dose Initially 5–10mg/24h PO up to max 80mg/24h PO
Perindopril erbumine	Dose Initially 4mg/24h PO up to max 8mg/24h PO
Perindopril arginine	Dose Initially 5mg/24h PO up to max 10mg/24h PO
Ramipril	Dose Initially 1.25–2.5mg/24h PO up to max 10mg/24h PO

Table 5.2 Starting an ACEi

Patients with significant comorbidity and/or taking other antihypertensive medications, as well as the frail and elderly, may need more cautious management when starting an ACEi and when increasing the dose
Before starting	Check U+E, document starting BP, identify target BP
First dose	Start with lowest dose and consider giving at bedtime to limit any problems with first-dose hypotension
In hospital	Increase dose daily/alternate days as BP allows, monitor U+E daily/alternate days
In community	Check U+E and BP at 7–10d after starting therapy or increasing dose. Increase dose every 14d until target BP reached

Acetylcysteine (eg Parvolex^®) Acetylcysteine helps replace the substrates necessary to eliminate the toxic products formed when normal hepatic metabolism of paracetamol is overwhelmed.

Dose In adults, 3 doses of acetylcysteine are given (5% glucose is preferred):

• 150mg/kg IV infusion in 200mL 5% glucose or 0.9% saline over 1h

• 50mg/kg IV infusion in 500mL 5% glucose or 0.9% saline over 4h

• 100mg/kg IV infusion in 1000mL 5% glucose or 0.9% saline over 16h.

Indication Mainly used in known or suspected paracetamol overdose ( p. 509). It should be commenced immediately in all patients calculated to have ingested >75mg/kg, those with a staggered overdose, or a blood paracetamol level above the treatment threshold on the nomogram in Fig. 5.1. Start treatment within 8h of ingestion—do not wait for level if patient presents close to or after this time as efficacy of acetylcysteine will decline rapidly after 8h. Discontinue treatment if the plasma concentration is later reported as below the treatment line and patient is asymptomatic with normal LFTs, creatinine, and PT. Discuss patients with acidosis, encephalopathy, worsening renal function, or PT prolongation with hepatologist on call (or at nearest liver centre if not available locally).

SE Flushing, rash, pruritus, urticaria, nausea, and vomiting are all relatively common during treatment. More severe anaphylactoid reactions (↓BP, ↑HR, bronchospasm) should be managed as per pp. 484–485 with infusion slowed or stopped.

Fig. 5.1 Paracetamol overdose treatment nomogram.

Reproduced from https://www.gov.uk/drug-safety-update/treating-paracetamol-overdose-with-intravenous-acetylcysteine-new-guidance. Contains public sector information licensed under the Open Government Licence v3.0.

Actrapid^® Insulin. See insulin.

Adenosine Nucleoside (antiarrhythmic). Dose 6mg rapid IV bolus; if needs repeated dose 12mg rapid IV bolus, then 12mg rapid IV bolus Indication Supraventricular tachycardia CI 2nd/3rd-degree heart block, sick sinus syndrome (unless pacemaker fitted), long QT syndrome, COPD/asthma Caution Pregnancy, recent MI, pericarditis, heart block, bundle branch block, accessory pathway, hypovolaemia, valvular lesions SE Nausea, sinus pause, bradycardia/asystole, flushing, angina, dizziness.

Adrenaline (epinephrine); anaphylaxis Catecholamine. Dose 0.5mg/STAT IM (0.5mL of 1:1000); repeat after 5min if inadequate response Indication Suspected anaphylaxis; if in doubt give it Caution Cerebro- and cardiovascular disease SE ↑HR, ↑BP, anxiety, sweats, tremor, arrhythmias.

Adrenaline (epinephrine); cardiac arrest Catecholamine. Dose 1mg/STAT IV (10mL of 1:10,000); repeat as per ALS algorithm Indication Cardiac arrest Caution As for ‘Adrenaline (epinephrine); anaphylaxis’ SE As for ‘Adrenaline (epinephrine); anaphylaxis’.

Aggrastat^® Glycoprotein IIb/IIIa inhibitor. See tirofiban.

Alteplase Plasminogen activator. See fibrinolytics.

Amiloride Potassium-sparing diuretic. Dose 5–10mg/24h PO (max 20mg/24h PO) Indication Oedema, potassium conservation when used as an adjunct to thiazide or loop diuretics for hypertension, congestive cardiac failure, hepatic cirrhosis with ascites CI Hyperkalaemia, anuria, Addison’s disease Caution Renal impairment, DM, pregnancy, and breastfeeding SE Abdominal pain, GI disturbances including bleeding.

Aminophylline; IV Theophylline/methylxanthine. Dose Loading 5mg/kg (based on ideal body weight) in 100mL 0.9% saline IVI over 20min; Maintenance 0.5mg/kg/h, make up 500mg in 500mL 0.9% saline (concentration = 1mg/mL) IVI Indication Reversible airways disease, severe acute asthma Caution Avoid loading dose if patient taking oral theophylline; cardiac disease, hypertension, epilepsy SE Tachycardia, palpitations, arrhythmia, convulsions Info Theophylline is only available as an oral preparation; aminophylline consists of theophylline and ethylenediamine which simply improves the drug’s solubility.

Monitoring aminophylline (theophylline)

Stop infusion 15min prior to sampling, take sample 4–6h after commencing an infusion 10–20mg/L (55–110micromol/L) ► Toxic >20mg/L (>110micromol/L) ► Signs of toxicity Arrhythmia, anxiety, tremor, convulsions ( OHAM3 p. 731)

Amiodarone; cardiac arrest Class III antiarrhythmic. Dose 300mg IV/STAT after third shock if patient remains in VF/pulseless VT Indication VF/pulseless VT.

Amiodarone; arrhythmias Class III antiarrhythmic. Dose Oral loading 200mg/8h PO for 1wk, then 200mg/12h PO for 1wk, then 200mg/24h PO as maintenance dose; IV loading. Initially 5mg/kg over 20–120min IVI (with ECG monitoring) then further infusion if necessary of up to 1.2g over 24h IVI Indication SVT, nodal and ventricular tachycardias, atrial fibrillation and flutter, VF (see above) CI Bradycardia, sinoatrial heart block, thyroid dysfunction, iodine sensitivity Caution Pregnancy, breastfeeding, thyroid disease, hypokalaemia, heart failure, elderly, bradycardia SE N+V, taste disturbance, raised transaminases, jaundice, bradycardia, hypotension, pulmonary toxicity, corneal deposits, skin discolouration Info Monitor LFTs and TFTs every 6mth.

Amlodipine See calcium-channel blockers.

Amoxicillin Beta-lactam. Dose 500mg–1g PO/IV 8h Indication Infection CI Penicillin allergy Caution Glandular fever, CMV infection, ALL/CLL SE N+V, diarrhoea, rash.

Ampicillin Beta-lactam. Dose 500mg–1g PO/IV 6h Indication Infection CI Penicillin allergy Caution Glandular fever, CMV infection, ALL/CLL SE N+V, diarrhoea, rash.

Antacids/alginates Dose See Table 5.3 Indications Acid reflux disease Caution Hepatic and renal impairment; if symptoms are severe or persist seek expert opinion SE Depends upon preparation used, see Table 5.3 Info The sodium load in these preparations can be significant and they should be used with caution in patients with hepatic impairment. The alginates increase the viscosity of the stomach contents and can protect the oesophageal mucosa from acid attack; the raft-forming alginates float on the surface of the stomach contents and may further reduce the symptoms of reflux.

Table 5.3 Antacids and alginates

Classification
Aluminium hydroxide	eg Alu-Cap® Dose 1 capsule 4 times daily and at bedtime CI hypophosphataemia, neonates SE constipation
Magnesium carbonate	Dose 10mL 3 times daily in water CI Hypophosphataemia SE diarrhoea, belching (due to CO2 liberation)
Magnesium trisilicate	Dose depends upon preparation, see BNF CI and SE See magnesium carbonate
Alginate raft-forming suspensions	eg Peptac® Dose 10–20mL after meals and at bedtime SE usually none
Other alginate preparations	eg Gastrocote® Dose 5–15mL 4 times daily (after meals and at bedtime) SE usually none

Antiemetics

Dose See Table 5.4 Indications N+V see Table 5.5; not all antiemetics are effective for all causes of N+V Caution and SE See Table 5.4 Info It is important to establish the cause of N+V.

Table 5.4 Antiemetic classification

Antihistamines	Cinnarizine, cyclizine, promethazine
Cyclizine	Dose 50mg/8h PO/IV/IM CI Heart failure SE Drowsiness, pain on injection, urinary retention, dry mouth, blurred vision
Phenothiazines	Chlorpromazine, droperidol, perphenazine, prochlorperazine, trifluoperazine
Prochlorperazine	Dose Consult BNF; 10mg/8h PO, 12.5mg/24h IM, 3–6mg/12h buccal CI Parkinson’s, epilepsy SE Extrapyramidal effects, hypotension, drowsiness, agitation
Dopamine antagonists	Domperidone, metoclopramide
Metoclopramide	Dose 10mg/8h PO/IV/IM CI Avoid in patients <21yr (especially ♀) and in bowel obstruction SE Extrapyramidal effects
5HT 3antagonists	Granisetron, ondansetron
Ondansetron	Dose 4–8mg/8h PO/IV/IM CI QT prolongation SE Constipation, headache, flushing, bradycardia, hypotension
Miscellaneous	Dexamethasone, benzodiazepines, hyoscine hydrobromide, nabilone, neurokinin receptor antagonists

Table 5.5 Causes of N+V and suggested antiemetic

Likely cause	Suggested antiemetics
Pregnancy	Promethazine, prochlorperazine, metoclopramide, ondansetron
Postoperative	In no particular order: 5HT3 antagonists, antihistamines (eg cyclizine), dexamethasone, phenothiazines (eg prochlorperazine), metoclopramide
Bowel obstruction	Treat the cause. Avoid metoclopramide
Motion sickness	Hyoscine hydrobromide, promethazine, cyclizine
Vestibular disorders	Betahistine (see BNF), antihistamine (eg cinnarizine, see BNF), phenothiazine (eg prochlorperazine)
Cytotoxic chemotherapy	Pre and post treatment with domperidone or metoclopramide; add in dexamethasone, 5HT3 antagonists. See BNF
Palliative care	Depends upon cause p. 93

Antihistamines H₁-receptor antagonists. Dose See Table 5.6 Indications Symptomatic relief of allergy (eg hayfever, allergic rhinitis, urticaria) Caution Avoid if possible in pregnancy and breastfeeding; consult BNF if renal or hepatic impairment; all antihistamines have the potential to cause sedation, some more so than others (Table 5.6); the sedating antihistamines also possess significant antimuscarinic activity and should be used with caution in prostatic hypertrophy, urinary retention, and in patients with angle-closure glaucoma SE Drowsiness, headache, antimuscarinic effects Info The drugs in this section are all antagonists at H₁ receptors; cimetidine and ranitidine are antagonists at H₂ receptors, and are useful for gastric acid suppression (see ranitidine).

Table 5.6 Antihistamines

Non-sedating antihistamines Acrivastine, cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, mizolastine, rupatadine
Cetirizine	Dose 10mg/24h PO Caution Halve dose if eGFR <30mL/min
Desloratadine	Dose 5mg/24h PO
Loratadine	Dose 10mg/24h PO
Sedating antihistamines Alimemazine, chlorphenamine, clemastine, cyproheptadine, hydroxyzine, ketotifen, promethazine
Chlorphenamine	Dose 4mg/4–6h PO (max 24mg/24h); 10mg/8h IV/IM (over 1min if given IV)

Apixaban Direct inhibitor of factor Xa. Indication and dose VTE prophylaxis after hip/knee replacement 2.5mg /12h PO for 14d for knees, 35d for hips (start 12–24h after surgery); Treatment of DVT/PE Initially 10mg/12h for 7d, then 5mg/12h for 6mths; Prophylaxis of recurrent PE/DVT Continue with 2.5mg/12h; Prophylaxis of stroke and systemic embolism in non-valvular atrial fibrillation and 1 risk factor (Such as previous stroke or TIA, symptomatic heart failure, DM, HTN, or >75yr) 5mg/12h (reduce dose to 2.5mg/12h if 2 of: >80yr, <61kg, or serum creatinine >133mmol/L) Caution Avoid in patients with significant bleeding risk. Wait 30h after last dose before removing epidural catheter and wait 5h until next dose SE Anaemia; bruising; haemorrhage; nausea Info No routine anticoagulant monitoring required (INR tests are unreliable).

Arthrotec^® NSAID. See diclofenac.

Asacol^® Aminosalicylate. See mesalazine.

Aspirin; antiplatelet NSAID. Dose Antiplatelet 75mg/24h PO; ACS/MI 300mg/STAT PO; Non-haemorrhagic stroke 300mg/24h PO for 14d then 75mg/24h PO Indication Secondary prevention of thrombotic cerebrovascular and cardiovascular events CI Active bleeding, children under 16 (Reye’s syndrome) Caution Pregnancy, breastfeeding, asthma, peptic ulceration, concomitant use of other anticoagulants SE Bronchospasm, GI irritation/haemorrhage.

Aspirin; analgesic/antipyretic NSAID. Dose 300–900mg/4–6h PO; max 4g/24h Indication Pain, pyrexia CI As for ‘Aspirin; antiplatelet’ Caution As for ‘Aspirin; antiplatelet’ SE As for ‘Aspirin; antiplatelet’.

AT II receptor antagonists Dose See Table 5.7; commence therapy in the same way as starting an ACEi ( p. 184) Indications Patients intolerant of ACEi; heart failure, hypertension, diabetic nephropathy, prophylaxis of cardiovascular events Caution Pregnancy and breastfeeding, renal artery stenosis/renal impairment, aortic stenosis, hyperkalaemia, known allergy to ACEi. May not be effective in African-Caribbean patients SE Postural hypotension, renal impairment and hyperkalaemia, taste disturbance, urticaria and angioneurotic oedema; cough can occur but is less common than with ACEi.

Table 5.7 AT II receptor antagonists

Candesartan	Dose Initially 4–8mg/24h PO up to max 32mg/24h PO
Irbesartan	Dose Initially 75–150mg/24h PO up to max 300mg/24h PO
Losartan	Dose Initially 25–50mg/24h PO up to max 100mg/24h PO
Valsartan	Dose Initially 80mg/24h PO up to max 320mg/24h PO

Atenolol See beta-blockers.

Atorvastatin HMG CoA reductase inhibitor. See statins.

Atropine; bradycardia Anticholinergic. Dose 500micrograms/STAT IV every 3–5min; max 3mg/24h Indication Bradycardia CI Glaucoma, myasthenia gravis, pyloric stenosis, prostatic enlargement Caution Down’s syndrome, GORD SE Transient bradycardia, antimuscarinic effects (constipation, urinary urgency and retention, pupil dilatation/loss of accommodation, dry mouth).

Atropine; cardiac arrest Anticholinergic. Dose 3mg/STAT IV Indication non-shockable cardiopulmonary arrest Caution None in the arrest situation SE As for ‘Atropine; bradycardia’ Info Atropine is no longer recommended for routine use in non-shockable cardiopulmonary arrest (see 2015 Resuscitation Guidelines).

Bactroban^® Antibacterial. See mupirocin.

Beclometasone Corticosteroid. Dose 200–400micrograms/12h INH Indication Chronic asthma (step 2 BTS guidelines) Caution TB SE Oral candidiasis, hoarse voice, paradoxical bronchospasm (rare) Info Different preparations/devices are not interchangeable and should be prescribed by brand name.

Bendroflumethiazide Thiazide diuretic. Dose Oedema 5–10mg/ alternate days PO; Hypertension 2.5mg/24h PO Indication Oedema, hypertension Caution DM, gout, SLE SE Dehydration, hypotension, electrolyte imbalance (especially ↓K⁺) Interaction ↑lithium levels and NSAIDs decrease effect.

Benzylpenicillin (penicillin G) Beta-lactam. Dose 0.6–1.2g/6h IV (max 4.8g/24h in divided doses) Indication Infection; skin, throat, endocarditis CI Penicillin allergy Caution History of allergy SE Diarrhoea Interaction Decrease effects of oral contraceptive pill, allopurinol increases risk of rash.

Beta-blockers Dose See Table 5.8 Indications Generic indications include: hypertension, angina, myocardial infarction, arrhythmias, heart failure, thyrotoxicosis, anxiety, migraine prophylaxis, benign essential tremor; topically for glaucoma Caution Pregnancy, breastfeeding, avoid abrupt withdrawal especially in patients with IHD (risk of rebound ↑HR/↑BP), 1st-degree AV block, DM (may mask symptoms ↓glucose), COPD CI Asthma, uncontrolled heart failure, marked bradycardia, ↓BP, 2nd/3rd-degree AV block, severe peripheral arterial disease SE Bradycardia, hypotension (especially postural), heart failure, bronchospasm, conduction disorders, peripheral vasoconstriction, headache, fatigue, sleep disturbance (often nightmares, insomnia), impotence Info The cardioselective β-blockers (Table 5.8) have less effect on β₂ receptors but are not cardiospecific and bronchoconstriction can still occur in susceptible patients. Water-soluble β-blockers (atenolol, nadolol, sotalol) are excreted by the kidneys and a dose reduction is often necessary in renal impairment; these are also less likely to cause sleep disturbance and nightmares.

Table 5.8 β-blockers. Doses show initial dose range for treatment of hypertension, doses vary with indication; consult BNF

Cardioselective
Atenolol	Dose 25–50mg/24h PO (100mg/24h max); also available IV
Bisoprolol	Dose 5–10mg/24h PO (20mg/24h max)
Metoprolol	Dose 50–100mg/24h PO (400mg/24h max); also available IV
Non-cardioselective
Carvedilol	Dose 12.5mg/24h PO (max 50mg/24h in divided doses)
Labetalol	Dose 100mg/12h PO (max 2.4g/24h in divided doses); also available IV
Propranolol	Dose 40–80mg/12h PO, increase weekly (max 320mg/24h in divided doses)
Sotalol	Used only to treat arrhythmias. Only commence after seeking expert advice Dose 40mg/12h PO (usual maintenance dose 80–160mg/12h PO); also available IV
Timolol	Used predominantly as eye drops for the treatment of glaucoma; case reports exist of this resulting in systemic effects

Betamethasone cream See topical corticosteroid.

Bezafibrate Fibrate. Dose 200mg/8h PO; modified-release preparations available, check BNF Indication Hyperlipidaemias unresponsive to diet and other measures CI Hypoalbuminaemia, primary biliary cirrhosis, gall bladder disease, nephrotic syndrome, pregnancy and breastfeeding Caution Renal impairment (see BNF for reduced dosing), hepatic impairment, hypothyroidism SE GI disturbance, anorexia, cholestasis.

Bisoprolol See beta-blockers.

Bowel cleansing preparations (Eg Klean-Prep^®, MoviPrep^®, Picolax®, etc) Laxative. Dose Consult BNF or local guideline Indications Prior to surgery, colonoscopy or radiological examination CI Bowel obstruction, toxic megacolon Caution Elderly, children, dehydration SE N+V, abdominal pain and distension, dehydration, electrolyte disturbance Info These agents should not be used in the treatment of constipation (see also laxatives).

Bricanyl^® β₂ agonist. See terbutaline.

Buccastem^® See antiemetics (phenothiazine).

Budesonide Corticosteroid. Dose 100–800micrograms/12h INH; 1–2mg/12h NEB Indication Chronic asthma (step 2 BTS guidelines) Caution TB SE Oral candidiasis, hoarse voice, paradoxical bronchospasm (rare).

Bupropion Treatment of nicotine dependence. Dose Commence 1–2wk before target smoking cessation date, initially 150mg/24h PO for 6d, then 150mg/12h PO (max single dose 150mg; max total daily dose 300mg) Indication Smoking cessation CI Acute alcohol or benzodiazepine withdrawal, severe hepatic cirrhosis, CNS tumour, history of seizures Caution Hepatic impairment, renal impairment, pregnancy and breastfeeding SE Dry mouth, GI disturbances, taste disturbance, agitation, anxiety.

Buscopan^® Antimuscarinic. See hyoscine butylbromide.

Calcichew^®/Calcichew^® D₃ Calcium salt. See calcium carbonate.

Calcium carbonate Calcium salt. Dose See BNF Indication Osteoporosis, ↓Ca²⁺ CI ↑Ca²⁺ (urine/serum), eg malignancy Caution History of renal stones, sarcoid, renal impairment SE GI disturbance, ↓HR, arrhythmias.

Calcium-channel blockers Dihydropyridines. Dose See Table 5.9 Indications ↑BP, prophylaxis of angina CI Unstable angina, cardiogenic shock, significant aortic stenosis, acute porphyria Caution Pregnancy, breastfeeding, heart failure SE Abdominal pain, N+V, flushing, palpitations, ↓BP, oedema, headache, sleep disturbance, fatigue Info The dihydropyridines relax smooth muscle and dilate both coronary and peripheral arteries. Nimodipine preferentially acts upon cerebral vascular smooth muscle and is used in the prevention and treatment of ischaemic neurological deficits following aneurysmal subarachnoid haemorrhage.

Table 5.9 Calcium-channel blockers (dihydropyridines)

Amlodipine	Dose Initially 5mg/24h PO up to max 10mg/24h PO
Felodipine	Dose Initially 5mg/24h PO up to max 10–20mg/24h PO
Nifedipine	Dose Depends upon preparation. Always specify specific brand for modified-release (MR) preparations; consult BNF
Nimodipine	Dose 60mg/4h PO starting within 4d of subarachnoid haemorrhage and continue for 21d; IV preparation available, consult BNF

Calcium-channel blockers Verapamil, diltiazem. Dose See Table 5.10 Indications ↑BP, prophylaxis of angina; verapamil is also used in the management of tachyarrhythmias CI Left ventricular failure, bradycardia, 2nd- or 3rd-degree AV dissociation, sick sinus syndrome Caution Pregnancy, patients taking β-blockers or other negatively chronotropic drugs, 1st-degree AV dissociation, acute phase of MI SE Bradycardia, ↓BP, heart block, dizziness, flushing, headache, oedema, GI disturbance Interactions Unlike the dihydropyridines, diltiazem and verapamil are negatively chronotropic and inotropic and should not generally be used in conjunction with β-blockers or other negatively chronotropic drugs.

Table 5.10 Calcium-channel blockers (verapamil, diltiazem)

Diltiazem	Dose Depends upon preparation; consult. Always specify specific brand for modified-release (MR) preparations; consult BNF
Verapamil	Dose Typically 40–120mg/8h PO for SVT; 80–120mg/8h PO for angina prophylaxis; 80–160mg/8h PO for ↑BP; 5–10mg over 5min IV with ECG monitoring for treatment of acute SVT (seek senior help before giving IV inotropes/chronotropes)

Calcium chloride Calcium salt. Dose 10mL of 10%; give 1mL/min IV Indication Emergency management of ↓Ca²⁺ CI ↑Ca²⁺ Caution History of renal stones, sarcoid, renal impairment SE Peripheral vasodilatation, ↓BP, injection-site reactions; more irritant than calcium gluconate.

Calcium gluconate Calcium salt. Dose 10mL of 10%; give over 3min IV Indication Emergency management of ↓Ca²⁺, ↑K⁺ CI ↑Ca²⁺ Caution History of renal stones, sarcoid, renal impairment SE Peripheral vasodilatation, ↓BP, injection-site reactions.

Calcium Resonium^® Calcium salt. Dose 15g/6–8h PO; PR preparations also available (see BNF) Indication ↑K⁺ (mild to moderate) Caution Pregnancy, breastfeeding SE GI disturbance Info Monitor K⁺.

Calpol^® Simple analgesic. See paracetamol.

Candesartan See AT II antagonists.

Canesten^® Imidazole antifungal. See clotrimazole.

Captopril See ACEi.

Carbamazepine Antiepileptic. Dose Initially 100mg/12h PO; Increase To max 2g/24h in divided doses; PR preparations available (see BNF) Indication Antiepileptic; generalized tonic–clonic, chronic pain, eg trigeminal neuralgia (see BNF for dosing) CI AV conduction abnormalities, history of bone marrow depression, acute porphyria Caution Pregnancy, breastfeeding, cardiac disease, Hong Kong Chinese/Thai origin, history of skin conditions SE N+V, dizziness, drowsiness, headache, ataxia, visual disturbance, cytopenias, hepatic dysfunction, skin disorders Interaction Enzyme inducer.

Monitoring carbamazepine

Random sample 20–50micromol/L (4–12mg/L) ► Toxic >50micromol/L (>12mg/L)

Carbimazole Antithyroid. Dose Initially 15–40mg/24h PO; Once euthyroid 5–15mg/24h PO as maintenance dose usually given for 12–18mth Indication Hyperthyroidism CI Severe blood disorders Caution Pregnancy, breastfeeding, hepatic impairment SE N+V, pruritus, rash, agranulocytosis.

Carvedilol See beta-blockers.

Cefaclor See cephalosporin.

Cefalexin See cephalosporin.

Cefotaxime See cephalosporin.

Cefradine See cephalosporin.

Ceftazidime See cephalosporin.

Ceftriaxone See cephalosporin.

Cefuroxime See cephalosporin.

Celecoxib NSAID/COX2 inhibitor. Dose 100–200mg/12h PO (max 400mg/24h in divided doses) Indication Pain and inflammation; osteoarthritis, rheumatoid arthritis and ankylosing spondylitis CI IHD, CVD, HF, allergy to any NSAID Caution Pregnancy, breastfeeding, hepatic impairment, renal impairment SE GI disturbance/bleeding, headache, dizziness Interaction Decreases effects of antihypertensives, increases toxicity of methotrexate, increased risk of renal impairment with ACEi, AT II antagonists, or ciclosporin.

Cephalosporin Dose See Table 5.11 Indications Infections (with known or suspected antimicrobial sensitivity (consult local guidelines)), surgical prophylaxis, other prophylaxis Caution Not known to be harmful in pregnancy, present in breast-milk in low concentration; 0.5–6.5% of patients who are penicillin-allergic will display allergy to cephalosporins as cephalosporins contain a beta-lactam ring as do the penicillins and carbapenems SE Diarrhoea (rarely antibiotic-associated colitis), N+V, abdominal discomfort, headache, allergic reactions Info Cephalosporins are amongst the antibiotics which are most likely to result in Clostridium difficile diarrhoea, the others being quinolones and clindamycin. As with all antibiotics, it is important to consult local guidelines as infectious agents have different susceptibilities depending upon geographical location.

Table 5.11 Cephalosporins (consult local guidelines)

First generation
Cefalexin	Dose 500mg (250–500mg) 8h PO Indications UTIs, respiratory tract infections, otitis media, sinusitis, skin and soft tissue infections
Cefradine	Dose 500mg (250–500mg) 6h PO Indications surgical prophylaxis but generally not used widely now
Second generation
Cefuroxime	Dose 750mg (750–1500mg) 8h IV, 500mg (250–500mg) 12h PO; Indications Gram-positive and Gram-negative bacteria; surgical prophylaxis
Third generation
Cefotaxime	Dose 1g (1–2g) 12h IV Indications better Gram-negative activity, but poorer coverage against Gram-positive bacteria than cefuroxime; penetrates the CSF
Ceftriaxone	Dose 1g (1–4g) 24h IV Indications better Gram-negative activity, but poorer coverage against Gram-positive bacteria than cefuroxime; penetrates the CSF
Ceftazidime	Dose 1g (1–2g) 8h IV or 2g/12h IV; Indications better Gram-negative activity, but poorer coverage against Gram-positive bacteria than cefuroxime; good activity against Pseudomonas

Cetirizine H₁ antagonist. See antihistamine.

Chloramphenicol; eye drops Antibiotic. Dose 1 drop 0.5%/2h TOP; reduce frequency as infection is controlled. Continue for 48h after symptoms resolve Indication Conjunctivitis, corneal abrasions, post eye surgery SE Transient stinging.

Chlordiazepoxide Benzodiazepine. Dose See Table 5.12 Indications Acute alcohol withdrawal treatment/prophylaxis Caution Pregnancy, breastfeeding, liver disease, renal impairment, respiratory disease (sleep apnoea, respiratory failure), reduce dose in the elderly, avoid abrupt withdrawal SE Respiratory depression, drowsiness, confusion, ataxia, amnesia, dependence Info Symptoms of acute alcohol withdrawal tend to occur 12–48h after the last alcoholic drink and usually subside 5–7d after the last drink. A reducing dose of chlordiazepoxide acts as a surrogate CNS depressant (which is the effect alcohol has upon the CNS) and it is uncommon for physical symptoms of withdrawal to present if patients are treated with this sort of regimen; always consider vitamin supplementation in these patients ( p. 105); consult local guidelines.

Table 5.12 Chlordiazepoxide regimen for alcohol withdrawal (local guidelines may differ from this suggested regimen)

Day 1	20mg/6h PO	Day 5	5mg/6h PO
Day 2	20mg/8h PO	Day 6	5mg/8h PO
Day 3	10mg/6h PO	Day 7	5mg/12h PO
Day 4	10mg/8h PO	Day 8	STOP

Chlorhexidine Antiseptic. Indication Skin preparation prior to surgery or other invasive procedures (eg vascular access, spinal/epidural anaesthesia), surgical hand scrub, oral hygiene, antiseptic lubricant (eg Hibitane®) CI Avoid contact with eyes, brain, meninges, middle ear and other body cavities SE Sensitivity, mucosal irritation.

Chlorphenamine H₁ antagonist See antihistamine.

Cimetidine Antihistamine (H₂ antagonist). See ranitidine.

Ciprofloxacin Quinolone. Dose 500–750mg/12h PO; 400mg/12h IV Indication Infections: GI, respiratory, urinary CI Pregnancy, breastfeeding, allergy to quinolones Caution Myasthenia gravis, seizures (reduced seizure threshold), adolescents/children, renal impairment SE N+V, diarrhoea, tendonitis (including tendon rupture) Interaction NSAIDs increase risk of seizure, increase levels of theophyllines, increase nephrotoxicity of ciclosporin, increase effect of warfarin.

Citalopram Selective serotonin re-uptake inhibitor. Dose 20mg/24h PO (max 40mg/24h) Indication Depression, panic disorder CI Active mania, QT interval prolongation Caution Pregnancy, epilepsy, cardiac disease, DM SE GI disturbance, anorexia, weight loss, ↓Na⁺, agitation Interaction MAOI within 2wk.

Clarithromycin Macrolide antibiotic. Dose 250–500mg/12h PO/IV Indication Atypical pneumonias, H. pylori CI Allergy Caution Pregnancy, breastfeeding, hepatic or renal impairment, concomitant use with statins SE GI upset, irritant to veins.

Clindamycin Antibiotic. Dose 150–450mg/6h PO; up to 4.8g/24h IV in 2–4 doses for life-threatening infections (consult BNF) Indication Gram-positive cocci and anaerobes; osteomyelitis, intra-abdominal infections, MRSA CI Diarrhoea Caution Breastfeeding, acute porphyria SE GI disturbance, antibiotic-associated colitis (namely C. diff ), hepatotoxicity, arthralgia; discontinue drug if patient develops new onset diarrhoea Interaction Increases neuromuscular blockade.

Clobetasol propionate cream See topical corticosteroids.

Clopidogrel Antiplatelet. Dose Loading 300mg/STAT PO; Maintenance 75mg/24h PO Indication Prevention of atherothrombotic events following MI/ACS/CVA CI Pregnancy, breastfeeding, active bleeding Caution Hepatic impairment, increased risk of bleeding, recent trauma/surgery SE GI disturbance, bleeding disorders Interaction Increased risk of bleeding with NSAIDs and anticoagulants; proton pump inhibitors may reduce effectiveness of clopidogrel.

Clotrimazole Imidazole antifungal. Dose 1% cream 2–3 applications/24h Indication Fungal skin infections, vaginal candidiasis Caution Avoid contact with eyes and mucous membranes, can damage condoms and diaphragms SE Local irritation.

Co-amoxiclav Beta-lactam with clavulanic acid. Dose 375–625mg/8h PO; 1.2g/8h IV Indication Infection; where amoxicillin alone is not appropriate CI Penicillin allergy Caution Renal impairment, glandular fever, CMV infection, ALL/CLL SE N+V, diarrhoea, rash.

Co-beneldopa Levodopa and dopa-decarboxylase inhibitor (benserazide). Dose Initially 50mg/6–8h PO, increased to 100mg/24h or 100mg/twice a week according to response; usual maintenance dose 400–800mg/day in divided doses Indication Parkinson’s disease Caution Severe pulmonary or cardiovascular disease, psychiatric illness, endocrine disorders, pregnancy and breastfeeding SE GI disturbances, taste disturbances, dry mouth, anorexia, arrhythmias and palpitations, postural hypotension, drowsiness, dystonia, dyskinesia.

Co-careldopa Levodopa and dopa-decarboxylase inhibitor (carbidopa). Dose Depends upon preparation, consult BNF Indication Parkinson’s disease Caution Severe pulmonary or cardiovascular disease, psychiatric illness, endocrine disorders, pregnancy and breastfeeding SE GI disturbances, taste disturbances, dry mouth, anorexia, arrhythmias and palpitations, postural hypotension, drowsiness, dystonia, dyskinesia.

Co-codamol Weak opioids with paracetamol. Dose 8/500mg Two tablets/4–6h PO (max eight tablets/24h in divided doses); 30/500mg Two tablets/4–6h PO (max eight tablets/24h in divided doses) Indication Pain CI Acute respiratory depression, paralytic ileus; codeine containing medicines should not be used in children under 12yr, or in any patient under the age of 18yr who undergoes removal of tonsils or adenoids for the treatment of sleep apnoea Caution Pregnancy (especially delivery), COPD, asthma, renal impairment, hepatic impairment SE N+V, constipation Info Co-prescribe laxatives if using opioids for >24h.

Codeine phosphate Weak opioid. Dose 30–60mg/4h PO/IM (max 240mg/24h in divided doses) Indication Pain CI Acute respiratory depression, paralytic ileus; codeine containing medicines should not be used in children under 12yr, or in any patient under the age of 18yr who undergoes removal of tonsils or adenoids for the treatment of sleep apnoea Caution Pregnancy (especially delivery), COPD, asthma, renal impairment, hepatic impairment; never give codeine phosphate IV SE N+V, constipation Info Co-prescribe laxatives if using opioids for >24h.

Combivent^® Antimuscarinic with β₂ agonist. Dose 500micrograms ipratropium bromide with 2.5mg salbutamol/PRN NEB Indication Asthma and other reversible airway obstruction, COPD Caution Prostatic hyperplasia, glaucoma SE Antimuscarinic effects (commonly dry mouth), fine tremor, tension headaches, arrhythmias.

Corsodyl^® Antiseptic. See chlorhexidine.

Cyclizine Antihistamine (H₁ antagonist). See antiemetics.

Dabigatran Direct thrombin inhibitor. Indication and dose VTE prophylaxis after hip/knee replacement 110mg 1–4h after surgery, followed by 220mg/12h for 9 d (30 d in hips) start 12–24h after 1st dose. If >75yr then initial dose is 75mg, followed by 150mg/12h for 9d (30d in hips). Treatment of DVT/PE and prophylaxis of recurrent PE/DVT Initial dose must follow at least 5 days treatment with a parenteral anticoagulant. 150mg/12h. If >75yr, renal impairment or at increased risk of bleeding: 110mg/12h. Prophylaxis of stroke and systemic embolism in non-valvular AF and 1 risk factor (Such as previous stroke or TIA, symptomatic heart failure, DM, HTN, or >75yr): 150mg/12h. If >75yr: 110mg/12h. SE Abdominal pain; anaemia; diarrhoea; dyspepsia; haemorrhage; nausea. Caution Avoid in patients with significant bleeding risk. Wait 6h after epidural catheter removal to restart dabigatran. Info Dose changes if receiving concomitant amiodarone or verapamil. No routine anticoagulant monitoring required (INR tests are unreliable).

Dalteparin Low-molecular-weight heparin. Dose Consult BNF Indication DVT/PE treatment and prophylaxis, ACS CI Bleeding disorders, thrombocytopenia, severe hypertension, recent trauma Caution Hyperkalaemia, hepatic or renal impairment SE Haemorrhage, thrombocytopenia, hyperkalaemia Interaction NSAIDs increase bleeding risk, effects increased by GTN.

Desloratadine Antihistamine (H₁ antagonist). See antihistamines.

Dexamethasone Corticosteroid. Dose See BNF Indication Cerebral oedema (malignancy), suppression of inflammation/allergic disorders, diagnosis of Cushing’s disease, chemotherapy induced N+V CI Systemic infection Caution Adrenal suppression, may precipitate tumour lysis syndrome in patients with some haematological malignancies SE Cushing’s syndrome, deranged blood glucose, osteoporosis, psychiatric reactions, raised WCC (specifically neutrophilia).

Diamorphine Opioid. Dose 2.5–5mg/4h SC/IM/IV Indication Severe pain, ACS/acute MI, acute pulmonary oedema, palliative care CI Respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients, phaeochromocytoma Caution Pregnancy (especially delivery), COPD, asthma, renal impairment, hepatic impairment SE N+V, constipation, respiratory depression, dry mouth Interaction MAOI Info Co-prescribe laxatives if using opioids for >24h.

Diazepam Benzodiazepine. Dose status epilepticus 5–10mg over 10min IV (max 20mg) or 10–40mg PR; Other short-term usage 2mg/8h PO (max 30mg/24h in divided doses) Indication Seizures, status epilepticus; Short term Anxiety, alcohol withdrawal, muscle spasms CI Respiratory depression, sleep apnoea, unstable myasthenia gravis, hepatic impairment Caution Pregnancy, breastfeeding, history of drug abuse, respiratory disease, muscle weakness, renal impairment SE Drowsiness, confusion, muscle weakness.

Diclofenac NSAID. Dose 50mg/8h PO/PR (max 150mg/24h in divided doses) Indication Pain, inflammation CI Pregnancy, peptic ulcer disease, hepatic impairment, congestive heart failure, ischaemic heart disease, peripheral arterial disease, cerebrovascular disease Caution Breastfeeding, renal impairment, asthma, GI disease, patients with significant risk factors for cardiovascular events (eg ↑BP, ↑lipids, DM, smoking) SE GI disturbance/bleeding, headache, dizziness Info Arthrotec^® is a preparation of diclofenac with misoprostol and may reduce GI side effects.

Digoxin Cardiac glycoside. Emergency IV loading dose 0.75–1mg over at least 2h IV Rapid oral loading dose 0.75–1.5mg over 24h in 3 divided doses PO (typically 500micrograms PO initially, followed by 250micrograms PO 6h later, and further 250micrograms PO 12h later if still tachycardic Maintenance dose 62.5–125micrograms/24h PO Indications Often 2nd-line agent in supraventricular tachyarrhythmias (commonly AF and atrial flutter), heart failure CI 2nd- or 3rd-degree AV dissociation, accessory conducting pathways (eg WPW) Caution Pregnancy, recent MI, sick sinus syndrome, renal impairment, elderly patients, ↓K⁺, ↓Mg²⁺ or ↑Ca²⁺ SE N+V, diarrhoea, bradyarrhythmias, tachyarrhythmias, dizziness, blurred or yellow vision Therapeutic monitoring (Table 5.13) should be undertaken if toxicity is considered (usually presents with N+V) or if rate control is poor Info Digoxin is now rarely used for rapid rate control, with other agents often being used in preference ( pp. 256–261) or DC cardioversion ( p. 546). Digoxin is most often used in the chronic rate control of supraventricular tachyarrhythmias and in heart failure. Digoxin does not restore sinus rhythm, it merely slows conduction at the AV node, limiting the number of impulses passing from the atria through to the ventricles thus controlling ventricular rate. It also acts as a positive inotrope, increasing the force of ventricular contraction If rate not adequately controlled After loading with digoxin, discuss with senior or cardiologist.

Monitoring digoxin

Optimum sampling time 6–12h post oral dose 1–2.6nmol/L (0.8–2microg/L); typically takes 7d to get to steady state ► Toxic >2.6nmol/L (>2microg/L). Toxicity can occur at levels <1.3nmol/L if patient has ↓K+ ► Signs of toxicity (see Table 5.13; OHAM3 p. 708)

Table 5.13 Digoxin toxicity

Symptoms	N+V, confusion, diarrhoea, yellow and blurred vision
Bloods	Toxicity precipitated by renal failure, ↓K+, ↓Mg2+, ↓T4 Check digoxin level (see ‘Monitoring digoxin’); toxic if >2.6nmol/L (>2micrograms/L)
ECG	Tachy- and bradyarrhythmias. ST depression/T-wave inversion
Complications	↑K+, cardiac dysrhythmias (tachy- and bradyarrhythmias)
Management	Airway, breathing, and circulation Continuous ECG monitoring Treat arrhythmias Consider digoxin-binding antibody fragments (DigiFab®, see BNF) if known or suspected digoxin overdose

Dihydrocodeine Weak opioid. Dose 30mg/4–6h PO (max 240mg/24h in divided doses); 50mg/4–6h IM Indication Pain CI Acute respiratory depression, paralytic ileus Caution Pregnancy (especially delivery), COPD, asthma, renal impairment, hepatic impairment; never give dihydrocodeine IV SE N+V, constipation Info Co-prescribe laxatives if using opioids for >24h.

Diltiazem See calcium-channel blockers.

Dipyridamole Antiplatelet. Dose 200mg modified-release/12h PO (max 600mg/24h in divided doses), non-modified-release preparations also available (see BNF) Indication Secondary prevention of ischaemic stroke and TIA, adjunct to oral anticoagulation for prophylaxis of thromboembolism associated with prosthetic heart valves Caution Breastfeeding, aortic stenosis, unstable angina, recent MI SE GI disturbance, dizziness, headache, myalgia Interaction Increases effect of warfarin, decreases effect of cholinesterase inhibitors.

Docusate sodium See laxatives.

Doxazosin α₁ antagonist. Dose 1mg/24h PO; increase gradually to 2–4mg/24h (max 16mg/24h) Indication Benign prostatic hyperplasia, hypertension CI Breastfeeding, hypotension Caution Pregnancy, hepatic impairment SE Postural hypotension, headache, dizziness, urinary incontinence Interaction Increases effects of antihypertensives.

Doxycycline Tetracycline. Dose 100–200mg 12–24h PO (consult BNF) Indication Respiratory tract infections, GU infections, anthrax, malaria prophylaxis CI Pregnancy, breastfeeding, renal impairment, age <12yr (stains growing teeth and bones) Caution Myasthenia gravis may worsen, exacerbates SLE SE GI disturbance including, dysphagia/oesophageal irritation, photosensitivity Interaction Decreased absorption with milk, decreases effects of oral contraceptive pill, mildly increases effects of warfarin.

Edoxaban Direct factor Xa inhibitor. Dose 30mg/24 if <60kg, 60mg/24 if > 61kg Indication Prophylaxis of stroke and systemic embolism in non-valvular AF and 1 risk factor (Such as previous stroke or TIA, symptomatic heart failure, DM, HTN, or >75yr); Treatment of DVT/PE and prophylaxis of recurrent PE/DVT Caution Mitral stenosis and prosthetic heart valves. Avoid in patients with significant bleeding risk. SE Anaemia; epistaxis; haemorrhage; nausea; pruritus; rash (rare = allergic oedema). Info No routine anticoagulant monitoring required (INR tests are unreliable). Monitor LFTs for the 1st year.

Enalapril See ACEi.

Enoxaparin Low-molecular-weight heparin. Dose DVT/PE prophylaxis 20–40mg/24h SC ( pp. 420–421); DVT/PE treatment 1.5mg/kg/24h SC; ACS treatment 1mg/kg/12h Indication DVT/PE treatment and prophylaxis, ACS CI Bleeding disorders, thrombocytopenia, severe hypertension, recent trauma Caution Hyperkalaemia, hepatic or renal impairment SE Haemorrhage, thrombocytopenia, hyperkalaemia Interaction NSAIDs increase bleeding risk, effects increased by GTN.

Epilim^® Antiepileptic. See valproate.

Erythromycin Macrolide antibiotic. Dose 500–1000mg/6h PO; 50mg/kg/24h IV in divided dose (typically 500–1000mg/6h IV) Indication Infection; atypical pneumonias. Commonly used in patients allergic to penicillins CI Allergy Caution Pregnancy, breastfeeding, hepatic or renal impairment, concomitant use with statins SE GI upset, irritant to veins.

Esomeprazole Proton pump inhibitor. Dose 20–40mg/24h PO Indication PUD, GORD, H. pylori eradication CI Breastfeeding Caution Pregnancy, hepatic impairment, gastric cancer SE GI disturbance, headache Interaction Proton pump inhibitors may reduce effectiveness of clopidogrel.

Felodipine See calcium-channel blockers.

Ferrous fumarate Iron supplement. Dose Consult BNF as depends upon formulation Indication Iron deficiency anaemia SE GI disturbance, dark stools.

Ferrous gluconate Iron supplement. Dose 600mg/8h PO (see BNF) Indication Iron deficiency anaemia SE GI disturbance, dark stools.

Ferrous sulfate Iron supplement. Dose 200mg/8h PO Indication Iron deficiency anaemia SE GI disturbance, dark stools.

Fibrinolytic drugs Plasminogen activator. Dose and indications Depends upon specific agent, see Table 5.14 (also p. 551) CI Recent haemorrhage, trauma or surgery, coagulopathies, aortic dissection, aneurysm, coma, history of cerebrovascular disease, peptic ulceration, menorrhagia, hepatic impairment; streptokinase should not be used again beyond 4d of first administration due to antibody formation and risk of allergic reactions Caution Pregnancy, following external chest compression, old age, hypertension SE N+V, bleeding, hypotension.

Table 5.14 Fibrinolytic drugs

In acute STEMI, fibrinolytic drugs should be used where primary cutaneous intervention (PCI) is not immediately available
Alteplase	Indications Acute MI, massive PE, acute ischaemic stroke Dose Consult BNF; given as an IV bolus followed by an IV infusion, followed by heparin infusion
Reteplase	Indications Acute MI Dose Consult BNF; given as two IV boluses 30min apart, followed by heparin infusion
Streptokinase	Indications Acute MI, DVT, PE, acute arterial thromboembolism, central retinal venous or arterial thrombosis Dose Consult BNF; typically 1.5million units in 100mL 0.9% saline over 1h IV. Do not repeat administration after 4d of initial dose due to risk of allergic reaction
Tenecteplase	Indications Acute MI Dose Consult BNF; given as an IV bolus, followed by heparin infusion
Urokinase	Indications Thromboembolic occlusive vascular disease; DVT, PE and peripheral vascular occlusion; occluded iv catheters and cannulae blocked by fibrin clot Dose Consult BNF

Finasteride Antiandrogen. Dose BPH 5mg/24h PO; male-pattern baldness 1mg/24h PO Indication BPH, male-pattern baldness CI Females and adolescents Caution Prostate cancer, urinary tract obstruction SE Gynaecomastia, testicular pain, sexual dysfunction.

Flagyl^® Antibiotic. See metronidazole.

Flecainide Class Ic antiarrhythmic. Dose Initial 100mg/12h PO; reduce to lowest effective dose over 3–5d; 2mg/kg over 10–30min slow IV (max 150mg) Indication VT, SVT CI HF, history of MI, heart block, bundle branch block Caution Patients with pacemakers, AF SE GI disturbance, dizziness, oedema, fatigue Interaction Duration of action increased by amiodarone, fluoxetine, quinine; myocardial depression with β-blockers/verapamil.

Flixotide^® Corticosteroid. See fluticasone.

Flucloxacillin Beta-lactam. Dose 250–500mg/6h PO; 250–2000mg/6h IV Indication Penicillin sensitive infections, endocarditis, osteomyelitis CI History of flucloxacillin-related jaundice, penicillin allergy SE Diarrhoea, abdominal pain Caution Renal impairment Interaction Decrease effects of oral contraceptive pill, allopurinol increases risk of rash.

Fluconazole Triazole antifungal. Dose 50–400mg/24h PO/IV Dependent on indication Indication Fungal meningitis, candidiasis, fungal prophylaxis CI Pregnancy, acute porphyria Caution Breastfeeding, hepatic or renal impairment SE GI disturbance.

Fludrocortisone Mineralocorticoid. Dose 50–300micrograms/24h PO Indication Addison’s disease, other adrenal insufficiency, postural hypotension CI Systemic infection without antibiotic cover Caution Adrenal suppression SE Sodium and water retention, hypertension.

Flumazenil Benzodiazepine antagonist. Dose 200micrograms/STAT IV, followed by 100micrograms/1min if required (max 1mg) Indication Benzodiazepine OD/toxicity CI Conditions dependent on benzodiazepines, eg status epilepticus Caution Benzodiazepine dependence, mixed OD SE N+V, dizziness, arrhythmias.

Fluoxetine Selective serotonin re-uptake inhibitor. Dose 20mg/24h PO (max 60mg/24h) Indication Depression, bulimia nervosa and OCD CI Active mania Caution Pregnancy, epilepsy, cardiac disease, DM, bleeding disorders, glaucoma SE GI disturbance, anorexia, weight loss, ↓Na⁺, agitation Interaction MAOI within 2wk.

Fluticasone Corticosteroid. Dose 100–500micrograms/12h INH (consult BNF) Indication Chronic asthma (step 2 BTS guidelines) Caution TB SE Oral candidiasis, hoarse voice, paradoxical bronchospasm (rare).

Folic acid Vitamin B9. Dose 400micrograms/24h PO before conception and until week 12 of pregnancy; 5mg/wk for preventing methotrexate side effects Indication Pregnancy, folate deficient megaloblastic anaemia, long-term methotrexate CI Malignancy Caution Never give alone for pernicious anaemia; can cause degeneration of spinal cord, undiagnosed megaloblastic anaemia SE GI disturbance.

Fondaparinux Factor Xa inhibitor. Dose 2.5mg/24h SC (2.5mg loading dose 6h post-op) Indication VTE prophylaxis and treatment, ACS CI Active bleeding, bacterial endocarditis Caution Pregnancy, breastfeeding, bleeding disorders, active PUD, recent surgery, epidural/spinal anaesthesia, hepatic or renal impairment SE Bleeding, purpura, anaemia, thrombocytopenia.

Furosemide Loop diuretic. Dose Typically 20–80mg/24h PO/IV Indication Oedema (LVF, pulmonary oedema), resistant hypertension CI Severe ↓K⁺ and ↓Na⁺, hypovolaemia, renal impairment Caution Hypotension SE GI disturbance, hypotension, electrolyte disturbances (↓K⁺, ↓Na⁺, ↓Mg²⁺) Interaction Increases toxicity of gentamicin, digoxin, NSAIDs Info IV doses >80mg should be infused at <4mg/min (risk of deafness).

Fusidic acid Antibiotic. Dose 2% topical cream 3–4 applications/24h; oral and IV preparations available (see BNF) Indication Staphylococcal skin infections; IV treatment Osteomyelitis, penicillin-resistant staphylococcal infections Caution Pregnancy, breastfeeding, monitor LFTs SE GI disturbance, reversible jaundice.

Fybogel^® See laxatives.

Gabapentin Antiepileptic. Dose day 1 300mg/24h PO; Continued Increase by 300mg/24h PO up to max 3.6g/24h in 3 divided doses Indication Epilepsy, neuropathic pain Caution Pregnancy, breastfeeding, renal impairment, DM, avoid abrupt withdrawal SE GI disturbance, headache, sleep disturbance Interaction Effects decreased by antidepressants.

Gentamicin Aminoglycoside. Dose Once daily 5–7mg/kg/24h IV adjust to serum concentration; other dosing regimens may be used (consult local guidelines) Indication Infection; sepsis, meningitis, endocarditis CI Myasthenia gravis Caution Pregnancy, breastfeeding, renal impairment SE Ototoxic, nephrotoxic Interaction Effects increased by loop diuretics, increases effects of warfarin.

Levels are typically taken 1 hr before next dose is due (but check local guidelines first)
Monitoring gentamicin	Peak 1h post IV dose 9–18micromol/L (5–10mg/L) Trough <4.2micromol/L (<2mg/L) ► Toxic >12mg/L (22micromol/L) ► Signs of toxicity tinnitus, deafness, nystagmus, vertigo, renal failure (OHCM10 p. 756). Will vary with once-daily regimen, check locally.

Glibenclamide See sulfonylureas.

Gliclazide See sulfonylureas.

Glipizide See sulfonylureas.

Glucagon Peptide hormone. Dose 1mg/PRN IM/SC/slow IV Indication Hypoglycaemia, in treatment of β-blocker overdose CI Phaeochromocytoma Caution Insulinoma, glucagonoma, chronic hypoglycaemia SE GI disturbance, ↓K⁺, hypotension.

Glycerin suppositories See laxatives.

Glyceryl Trinitrate nitrate. See GTN.

GTN sublingual/transdermal Nitrate. Dose 1–2 sprays/PRN SL; 0.3–1mg/PRN SL Indication Prophylaxis and treatment of angina, left ventricular failure CI Hypotensive conditions, hypovolaemia, aortic stenosis Caution Pregnancy, breastfeeding, hypothyroidism, recent MI, head trauma SE Postural hypotension, tachycardia, headache Info Transdermal patches are available, see BNF—patients may develop tolerance (tachyphylaxis) to nitrates and as such it is suggested to ensure patients have a nitrate-free period for 4–8h to prevent this; it is usual to have this period overnight when the effects of nitrates are least likely to be needed.

GTN IV infusion Nitrate. Dose 10–200micrograms/min IVI GTN. For typical prescription see Fig. 5.2. Indication Left ventricular failure, ongoing ischaemic chest pain refractory to SL nitrates CI Hypotensive conditions, hypovolaemia, aortic stenosis Caution Pregnancy, breastfeeding, hypothyroidism, recent MI, head trauma SE Postural hypotension, tachycardia, headache Info Patients may develop tolerance (tachyphylaxis) to nitrates and as such it is suggested to ensure patients have a nitrate-free period for 4–8h to prevent this; it is usual to have this period overnight when the effects of nitrates are least likely to be needed.

Fig. 5.2 Example of a GTN infusion.

Haloperidol Antipsychotic (butyrophenone). Dose Antiemetic 0.5–3mg/8h PO/IV; Other 0.5–10mg/8h PO/IM/IV Indication Schizophrenia, agitation, N+V, motor tics, intractable hiccups CI Comatose/CNS depression Caution Pregnancy, breastfeeding, hepatic or renal impairment, cardiovascular disease, Parkinson’s, epilepsy SE Extrapyramidal symptoms, cardiac arrhythmias (QTc prolongation).

Heparin Glycosaminoglycan (potentiates antithrombin III). Dose Loading dose 5000units or 75units/kg IV; Maintenance 18units/kg/h IVI (titrate dose to keep APTT within therapeutic range); Prophylactic dose 5000units/12h SC (seldom used as LMWH have similar benefits and fewer side effects) Indication Rapid anticoagulation, treatment and prophylaxis of DVT/PE, ACS CI Bleeding disorders, thrombocytopenia, severe hypertension, recent trauma, history of heparin-induced thrombocytopenia (HIT, p. 421) Caution ↑K⁺, hepatic or renal impairment SE Haemorrhage, thrombocytopenia, ↑K⁺ Interaction NSAIDs increase bleeding risk, effects increased by GTN.

Humalog^® See insulin.

Humalin^® See insulin.

Hydralazine Vasodilator (arterial >> venous). Dose hypertension 25–50mg/12h PO; 5–10mg slow IV titrated to effect (can repeat after 30min); Heart failure 25–75mg/6h PO Indication Hypertension, heart failure CI SLE, severe tachycardia, myocardial insufficiency Caution Pregnancy, breastfeeding, hepatic or renal impairment, ischaemic heart disease, cerebrovascular disease SE Tachycardia, palpitation, hypotension, SLE-like syndrome after long-term, rebound hypertension on stopping therapy, fluid retention.

Hydrocortisone cream See topical corticosteroids.

Hydrocortisone IV/PO Corticosteroid. Dose Acute 100–250mg/6h IV; Chronic 20–30mg/24h PO in divided doses Indication Adrenocortical insufficiency, acute allergic/inflammatory reactions CI Systemic infection Caution Adrenal suppression SE Cushing’s syndrome, DM, osteoporosis, dyspepsia.

Hydroxocobalamin Vitamin B₁₂. Dose Macrocytic anaemia without neurological involvement Initially 1mg three times a week IM, after 2wk 1mg/3mth IM; Macrocytic anaemia with neurological involvement Initially 1mg on alternate days IM until no further improvement, then 1mg/2mth IM Indication Pernicious anaemia, other macrocytic anaemias with neurological involvement Caution Do not give before diagnosis fully established SE N+V, headache, dizziness.

Hyoscine butylbromide Anticholinergic. Dose 20mg/6h PO (max 80mg/24h in divided doses); 20mg/STAT IV/IM repeated after 30min (max 100mg/24h in divided doses) Indication GI/GU smooth muscle spasm CI Myasthenia gravis Caution Pregnancy, glaucoma, GI obstruction, prostatic hyperplasia, urinary retention SE Antimuscarinic effects, drowsiness.

Hyoscine hydrobromide Anticholinergic. Dose Antiemetic 300micrograms/6h PO (max 900micrograms/24h in divided doses); Excessive respiratory secretions 200–600micrograms/4–8h SC Indication Motion sickness, excessive respiratory secretions CI Glaucoma Caution Pregnancy, GI obstruction, prostatic hyperplasia, urinary retention SE Antimuscarinic effects, sedative Interaction Decreases effects of sublingual GTN.

Ibuprofen NSAID. Dose 200–400mg/6h PO (max 2.4g/24h in divided doses) Indication Pain, inflammation CI Pregnancy, peptic ulcer disease Caution Breastfeeding, hepatic or renal impairment, asthma, GI disease SE GI disturbance/bleeding, headache Interaction Decreases effects of antihypertensives, increases toxicity of methotrexate.

Insulatard^® See insulin.

Insulin Dose When starting or changing SC doses, liaise with diabetes team (eg diabetes nurse specialist); infusion see Table 5.15 Indications DM, diabetic ketoacidosis, hyperkalaemia, maintenance of euglycaemia in critical care and post MI CI Hypoglycaemia Caution May need dose adjustments in pregnancy, breastfeeding, renal and hepatic impairment, see BNF SE Hypoglycaemia, local reactions and fat hypertrophy at injection site, rarely allergic reactions Info Table 5.16 is not an exhaustive list of insulins. In addition to these single preparations of insulin, so-called biphasic mixtures of two different insulins are also used and often consist of a rapid- or short-acting insulin and a longer-acting insulin (in different proportions).

Table 5.15 IV infusions of insulins

Indication
Hyperkalaemia ( pp. 399–403)	50mL of 50% glucose with 10units soluble insulin (eg Actrapid®) IVI over 10min
Sliding scale ( p. 333)	50mL of 0.9% saline with 50units soluble insulin (eg Actrapid®), often infused at 0–7mL/h depending upon the patient’s blood sugar

Table 5.16 Properties of common subcutaneous insulins

Type of insulin	Example	Onset	Peak	Max duration
Rapid acting
Aspart	Novorapid®	15–30min	0.5–1.25h	4–6h
Lispro	Humalog®	15–30min	0.5–1.25h	4–6h
Glulisine	Apidra®	15–30min	0.5–1.25h	4–6h
Short acting
Soluble	Actrapid®	30–60min	2–3h	6–8h
Intermediate and long acting
Isophane	Insulatard®	2–4h	6–10h	14–18h
Glargine	Lantus®	3–4h	8–16h	20–24h
Detemir	Levemir®	3–4h	6–8h	~20h

Ipratropium Anticholinergic. Dose Chronic 20–40micrograms/6h INH (max 80micrograms/6h); Acute 250–500micrograms/4–6h NEB Indication Bronchospasm; chronic and acute Caution Glaucoma, prostatic hyperplasia SE Minimal antimuscarinic effects.

Iron See ferrous preparations.

ISMN Nitrate. See isosorbide mononitrate.

ISMO Nitrate. See isosorbide mononitrate.

Isoket^® Nitrate. See isosorbide dinitrate.

Isosorbide dinitrate IV infusion Nitrate. Dose 2–10mg/h IVI Indication Left ventricular failure, ischaemic chest pain CI Hypotensive conditions, hypovolaemia, aortic stenosis Caution Pregnancy, breastfeeding, hypothyroidism, recent MI, head trauma SE Postural hypotension, tachycardia, headache Info Patients may develop tolerance (tachyphylaxis) to nitrates if infused for prolonged periods, though there are obvious risks about stopping a nitrate infusion; consult senior.

Isosorbide mononitrate Nitrate. Dose initially 20mg breakfast and lunchtime PO then 40mg breakfast and lunchtime PO (max 120mg/24h in divided doses) Indication Prophylaxis of angina, adjunct in congestive heart failure Caution As GTN SE Postural hypotension, tachycardia, headache Info Patients may develop tolerance (tachyphylaxis) to nitrates and as such it is suggested to ensure patients have a nitrate-free period for 4–8h to prevent this; it is usual to have this period overnight when the effects of nitrates are least likely to be needed, hence prescribing them to be given at breakfast and lunchtime rather than 8am and 8pm.

Istin^® See calcium-channel blockers.

Lactulose See laxative.

Lamotrigine Antiepileptic. Dose Initially 25mg/24h PO for 14d; Then 50mg/24h PO for 14d, increase by max 50–100mg/24h every 7–14d until seizures controlled (max 500mg/24h) Indication Epilepsy Caution Requires close monitoring of serum levels, pregnancy, breastfeeding, hepatic or renal impairment, avoid rapid withdrawal SE Rash/severe skin reactions, cerebellar symptoms, cytopenias.

Lansoprazole Proton pump inhibitor. Dose 30mg/24h PO for 4–8wk, 15mg/24h PO maintenance Indication Prophylaxis and treatment of peptic ulcers, GORD, H. pylori eradication, Zollinger–Ellison syndrome CI Pregnancy Caution Breastfeeding, hepatic impairment, gastric cancer SE GI disturbance, headache Interaction Proton pump inhibitors may reduce effectiveness of clopidogrel Info Also available as a FasTab^® which dissolves in the mouth and is useful in patients who are NBM.

Laxative Dose See Table 5.17 Indications Treatment and prophylaxis of constipation ( pp. 316–317) Caution Confirm the patient is constipated and consider causes of constipation SE See Table 5.17 Info Chronic use of laxatives can lead to electrolyte imbalances and gut dysmotility. Ensure adequate water intake and increase fibre intake where possible. Always consider faecal impaction and other causes of obstruction before commencing oral laxatives. Combinations of laxatives from different groups can be used in severe constipation (eg lactulose and senna).

Table 5.17 Laxatives

Classification
Bulk-forming laxatives	Eg Fybogel®, Normacol® CI Difficulty in swallowing, intestinal obstruction, colonic atony, faecal impaction SE Diarrhoea, flatulence, abdominal distension, gastrointestinal obstruction
Fybogel®	1 sachet or two 5mL spoons in water/12h PO
Stimulant laxatives	Eg bisacodyl, docusate, glycerol, senna CI Intestinal obstruction, acute surgical abdomens, active inflammatory bowel disease, dehydration SE Diarrhoea, hypokalaemia, abdominal pain, N+V Info Co-danthramer should only be used in the terminally ill as potentially carcinogenic
Bisacodyl	5–10mg/nocte PO or 10mg/mane PR
Co-danthramer	1–2 capsules/nocte PO
Docusate sodium	200mg/12h PO (max 500mg/24h PO in divided doses)
Glycerin supps	1 suppository/PRN PR, max 4 in 24h
Senna	2 tablets/nocte PO or 10mL/nocte PO
Faecal softeners	Eg arachis oil, liquid paraffin Info Infrequently used CI Peanut allergy
Osmoticlaxatives	Eg lactulose, Movicol®, magnesium salts, rectal phosphates (eg Fleet® enema), rectal sodium citrate (eg Microlette®) CI Intestinal obstruction, colonic atony SE Diarrhoea, flatulence, abdominal distension and discomfort, nausea; local irritation with rectal preparations
Lactulose	10–15mL/12h PO
Movicol®	1–3 sachets/24h PO
Phosphate enemas	1/PRN PR, max 2 in 24h
Microlette®	1/PRN PR, max 2 in 24h

Levothyroxine Thyroid hormone (T₄). Dose Typically 50–200micrograms/24h PO at breakfast Indication Hypothyroidism CI Thyrotoxicosis Caution Pregnancy, breastfeeding, panhypopituitarism, adrenal insufficiency, cardiovascular disorders, DM SE Hyperthyroid-like symptoms; GI disturbance, tremors, restlessness, flushing Interaction Increases effects of TCAs and warfarin, decreases effects of propranolol.

Lidocaine Local anaesthetic (amide). Dose Local anaesthesia 1/2/4% solution SC (max 3mg/kg (max total dose 200mg)); Antiarrhythmic See BNF Indication Local anaesthesia, ventricular arrhythmias (alternative to amiodarone) CI Myocardial depression, atrioventricular block, sinoatrial node disorders Caution Pregnancy, hepatic or renal impairment, epilepsy, severe hypoxia/hypovolaemia SE Dizziness, drowsiness, confusion, tinnitus Interaction Increased myocardial depression with β-blockers and other antiarrhythmics, increased risk of arrhythmias with antipsychotics.

Lignocaine Local anaesthetic (amide). See lidocaine.

Lisinopril See ACEi.

Lithium Lithium salt (mood stabilizer). Dose See BNF Indication Mania, bipolar disorder CI Pregnancy, breastfeeding, untreated hypothyroidism, Addison’s disease Caution Thyroid disease, myasthenia gravis SE GI upset, thirst, polyuria Interaction Diuretics, NSAIDs Info Lithium citrate and lithium carbonate doses are not simply interchangeable d/w senior/pharmacist; on stable regimens monitor level every 3mth. The NPSA have published guidance on the ‘safer use of lithium’ and this should be consulted before commencing lithium therapy.¹

Monitoring lithium

Optimum sampling time 4–7d after commencing treatment 12h post dose 0.4–1mmol/L ► Early signs of toxicity (Li+ >1.5mmol/L) tremor, agitation, twitching, thirst, polyuria, N+V ► Late signs of toxicity (Li+ >2mmol/L) spasms, coma, fits, arrhythmias, renal failure ( OHAM4 p. 716)

Loperamide Opioid (antimotility). Dose 4mg PO initially then 2mg PO following every loose stool (max 16mg/24h in divided doses) Indication Diarrhoea, control of high output stoma CI Pregnancy, IBD, any condition where peristalsis should not be stopped; constipation, ileus, megacolon Caution Hepatic impairment, can promote fluid and electrolyte depletion in the young SE Abdominal cramps, constipation, dizziness Info Loperamide should not be used in infective diarrhoeas or diarrhoea associated with IBD.

Loratadine H₁ antagonist. See antihistamine.

Lorazepam Benzodiazepine. Dose Sedation/anxiety 1–4mg/24h PO/IM/IV; Seizures 4mg slow IV (repeated once after 10min if needed) Indication Sedation, seizures, status epilepticus CI Respiratory depression, sleep apnoea, unstable myasthenia gravis, severe hepatic impairment Caution Pregnancy, breastfeeding, history of drug abuse, respiratory disease, muscle weakness, renal impairment SE Drowsiness, confusion, muscle weakness.

Losartan See AT II antagonists.

Magnesium sulfate Magnesium salt. Dose 2–4g IV over 5–15min often followed by an infusion (see BNF) Indication Arrhythmias, MI, acute severe asthma, pre-eclampsia/eclampsia, ↓Mg²⁺ Caution Pregnancy, monitor BP, RR, urinary output, hepatic or renal impairment SE N+V, hypotension, thirst, flushed skin Interaction Risk of hypotension with calcium-channel blockers Info Magnesium sulfate 1g equivalent to ~4mmol.

Monitoring magnesium	Levels should be checked every 6h while on IV therapy or more urgently if indicated; Therapeutic range 1.7–3.5mmol/L
0.7–1.0mmol/L	Normal plasma range
1.7–3.5mmol/L	Therapeutic range
2.5–5.0mmol/L	ECG changes (QRS widens)
4.0–5.0mmol/L	Reduction in tendon reflexes
>5.0mmol/L	Loss of deep tendon reflexes
>7.5mmol/L	Heart block, respiratory paralysis, CNS depression
>12mmol/L	Cardiac arrest

Maxolon^® Antiemetic (dopamine antagonist). See metoclopramide.

Mannitol Polyol (osmotic diuretic). Dose 0.25–2g/kg/4–8h over 30–60min IVI (max 3 doses) Indication Cerebral oedema, glaucoma CI Pulmonary oedema, cardiac failure Caution Pregnancy, breastfeeding, renal impairment SE hypotension, fluid and electrolyte imbalance.

Mebeverine Antispasmodic (antimuscarinic). Dose 135–150mg/8h PO (20min before food) Indication GI smooth muscle cramps; IBS/diverticulitis CI Paralytic ileus Caution Pregnancy, acute porphyria SE Very rarely rash, urticaria.

Meropenem Carbapenem antibiotic. Dose 500–1000mg/8h IV (dose doubled in severe infections) Indication Aerobic and anaerobic Gram-positive and Gram-negative infections Caution Pregnancy, breastfeeding, hepatic or renal impairment, sensitivity to beta-lactams SE GI disturbance including antibiotic associated colitis, headache, deranged LFTs.

Mesalazine Aminosalicylate. Dose Depends upon formulation, consult BNF; PO and PR preparations available Indication Mild/moderate active ulcerative colitis and maintenance of remission CI Salicylate allergy, coagulopathies Caution Pregnancy, breastfeeding, hepatic or renal impairment SE GI upset, bleeding disorders.

Metformin Biguanide. Dose Initially 500mg/24h PO with breakfast; After 1wk 500mg/12h PO; After further 1wk 500mg/8h PO if required (max 2g/24 in divided doses) Indication Type 2 DM, polycystic ovarian syndrome CI Hepatic or renal impairment Caution Ketoacidosis, potential increased risk of lactic acidosis, iodine-containing contrast, general anaesthesia SE GI disturbance, metallic taste.

Methadone Opioid. Dose Usual range 60–120mg/24h PO; should not be given more frequently than 12h if on prolonged use; establish the patient’s dose from the usual dispensing pharmacy, the patient may not tell you accurate information Indication Aid in withdrawal from opioid dependence, chronic pain CI Acute respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients, phaeochromocytoma Caution Pregnancy (especially delivery), arrhythmias, hepatic or renal impairment SE N+V, constipation, respiratory depression, dry mouth Interaction MAOI within 2wk.

Methotrexate Dihydrofolate reductase inhibitor. Dose 2.5–10mg/wk PO (max 25mg/wk) Indication Rheumatoid arthritis, Crohn’s disease, psoriasis, ALL, non-Hodgkin’s lymphoma CI Pregnancy, breastfeeding, hepatic or renal impairment, active infection, immunodeficient syndromes Caution Blood disorders, effusions (especially ascites), peptic ulcer, ulcerative colitis SE GI disturbance/mucositis, pulmonary fibrosis, pneumonitis, myelosuppression Interaction NSAIDs, co-trimoxazole, trimethoprim Info Patients usually also prescribed folic acid during treatment with methotrexate.

Methylprednisolone Corticosteroid. Dose 2–40mg/24h PO; 10–500mg/24h IV/IM (exceptionally, up to 1g/24h for up to 3d) Indication Acute inflammatory disease, cerebral oedema (associated with malignancy), graft rejection CI Systemic infection Caution Adrenal suppression SE Cushing’s syndrome, DM, osteoporosis Interaction Duration decreased by rifampicin, carbamazepine, phenytoin; duration of action increased by erythromycin, ketoconazole, ciclosporin.

Metoclopramide Dopamine antagonist. See antiemetic.

Metoprolol See beta-blockers.

Metronidazole Antibiotic. Dose 400mg/8h PO; 500mg/8h IV Indication Anaerobic and protozoal infections, abdominal sepsis, Clostridium difficile diarrhoea Caution Pregnancy, breastfeeding, hepatic impairment, alcohol use SE GI disturbance, metallic taste, oral mucositis Interaction Can increase lithium and phenytoin levels, increases effects of warfarin.

Midazolam Benzodiazepine. Dose 1–10mg IV titrated to effect Indication Conscious sedation, sedation in anaesthesia CI Breastfeeding, respiratory depression, sleep apnoea, unstable myasthenia gravis Caution Pregnancy, hepatic or renal impairment, history of drug abuse, respiratory disease, muscle weakness SE Drowsiness, confusion, muscle weakness.

Misoprostol Prostaglandin E₁ analogue. Dose treatment 800micrograms/24h PO in divided dose; prophylaxis 200micrograms/6–12h PO Indication Prophylaxis and treatment of peptic ulcers CI Pregnancy, breastfeeding Caution Cardiovascular/cerebrovascular disease SE Diarrhoea.

Mixtard^® See insulin.

Montelukast Leukotriene receptor antagonist. Dose 10mg/24h PO in evening Indication Chronic asthma (BTS guidelines), allergic rhinitis Caution Pregnancy, breastfeeding SE Abdominal pain, headache, rarely Churg–Strauss syndrome.

Morphine Opioid. Dose 2.5–10mg/4h IV titrated to effect; 5–10mg/4h IM/SC Indication Acute severe pain, chronic pain, acute MI, acute LVF CI Acute respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients Caution Pregnancy (especially delivery), COPD, asthma, arrhythmias, renal impairment, hepatic impairment SE N+V, constipation, respiratory depression, dry mouth Info Co-prescribe laxatives if using opioids for >24h.

MST Continus^® Opioid. See oral morphine.

Mupirocin Antibacterial. Dose Apply to skin up to 3 times/24h Indication Bacterial skin infections Caution Pregnancy, breastfeeding, renal impairment SE Local reactions; urticarial, pruritus, burning sensation, rash.

N-acetylcysteine Amino acid derivative. See acetylcysteine.

Naloxone Opioid receptor antagonist. Dose 0.4–2.0mg IV/IM/SC, repeat after 2min if needed (max 10mg) Indication Opioid reversal during OD/overtreatment Caution Pregnancy, physical dependence on opioids, cardiovascular disease SE N+V, hypotension BNF Emergency treatment of poisoning.

Narcan^® Opioid receptor antagonist. Narcan^® is a brand name for naloxone that is no longer used. See naloxone for opioid overdose or reversal of narcosis.

Nefopam Centrally acting non-opioid analgesic. Dose 30–60mg/8h PO (max 90mg/8h PO) Indication Moderate pain CI Convulsive disorders Caution Pregnancy, breastfeeding, hepatic or renal impairment, elderly, urinary retention SE N+V, nervousness, urinary retention, dry mouth, lightheadedness, may colour urine pink.

Nicorandil Potassium channel activator. Dose 5–10mg/12h PO (max 30mg/12h in divided doses) Indication Angina prophylaxis and treatment (not 1st line) CI Breastfeeding, hypotension, LVF with low filling pressures Caution Pregnancy, hypovolaemia, acute pulmonary oedema, MI SE Headache, flushing, GI disturbance.

Nifedipine See calcium-channel blockers.

Nitrofurantoin Antibiotic. Dose 50–100mg/6h PO; take with food Indication Urinary tract infections CI Pregnancy, breastfeeding, renal impairment, G6PD deficiency, infants <3mth, acute porphyria Caution Hepatic impairment, anaemia, DM, electrolyte imbalance, vitamin B₁₂/folate deficiency, lung disease SE Anorexia, GI disturbance, acute and chronic pulmonary reactions.

NOAC The acronym NOAC originally represented ‘Novel Oral Anticoagulants’, however since these drugs have now been in practice for 6yr the term ‘non-vitamin K antagonist oral anticoagulant’ to represent NOAC is preferred. This distinguishes them from warfarin. The current NOACs used in the UK include apixaban, dabigatran, edoxaban, and rivaroxaban. See each of these drugs individually for more detailed information.

Nurofen^® NSAID. See ibuprofen.

Nystatin Polyene antifungal. Dose 100 000 units (1mL)/6h PO; topical gel PRN Indication Candidiasis; oral, skin Caution GI absorbance minimal SE GI disturbance (at high doses), oral irritation, rash.

Omeprazole Proton pump inhibitor. Dose 10–40mg/24h PO; IV preparation available for endoscopically proven bleeding ulcers (consult BNF/local guidelines) Indication Prophylaxis and treatment of peptic ulcers, GORD, H. pylori eradication Caution Hepatic impairment (no more than 20mg/24h), can mask gastric cancer SE GI disturbance, headache, dizziness Interaction Proton pump inhibitors may reduce effectiveness of clopidogrel.

Ondansetron See antiemetics (5HT₃ receptor antagonist).

Oral morphine Opioid. Dose oral solution 5–20mg/4h PO; tablets 5–20mg/4h PO; 12h slow release preparations 10–30mg/12h PO, adjust to response (larger dose tablets available; seek senior/specialist advice) Indication Severe pain, chronic pain CI Acute respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients, phaeochromocytoma Caution Pregnancy (especially delivery), COPD, asthma, arrhythmias, renal impairment, hepatic impairment SE N+V, constipation, respiratory depression, dry mouth Info Co-prescribe laxatives if using opioids for >24h.

Oramorph^® Opioid. See oral morphine.

Oseltamivir (Tamiflu^®) Antiviral. Dose Treatment of influenza 75mg/12h PO for 5d; Prevention of influenza 75mg/24h PO for 10d Indication Treatment of influenza if started within 48h of the onset of symptoms, post-exposure prophylaxis of influenza Caution Renal impairment, pregnancy and breastfeeding (use only if potential benefit outweighs risk (eg during a pandemic)) SE GI disturbances, headache, arrhythmias, convulsions, thrombocytopenia.

Oxybutynin Antimuscarinic. Dose 5mg/8–12h PO, increase if required (max 20mg/24h in divided doses); modified-release preparations also available Indication Detrusor instability; urinary frequency, urgency and incontinence CI Pregnancy, breastfeeding, bladder outflow/GI obstruction, myasthenia gravis Caution Hepatic or renal impairment, prostatic hyperplasia, autonomic neuropathy SE Antimuscarinic effects, GI disturbance.

Oxycodone Opioid. Dose 5mg/4–6h PO (max 400mg/24h); 1–10mg/4h IV/SC titrated to effect Indication Pain; moderate to severe CI Acute respiratory depression, paralytic ileus, chronic constipation, acute abdomen, raised ICP/head trauma, hepatic or renal impairment if severe, acute porphyria, cor pulmonale, comatose patients Caution Pregnancy, COPD, asthma, arrhythmias, renal impairment, hepatic impairment SE N+V, constipation, respiratory depression, dry mouth Info 10mg PO oxycodone is equivalent to 20mg PO morphine. 1mg IV oxycodone is equivalent to 2mg PO oxycodone. Info Co-prescribe laxatives if using opioids for >24h.

OxyContin^® Opioid. Modified release form of oxycodone.

OxyNorm^® Opioid. Immediate-acting form of oxycodone.

Oxytetracycline Tetracycline antibiotic. Dose 250–500mg/6h PO Indication Acne vulgaris, rosacea CI Pregnancy, breastfeeding, renal impairment, age <12yr (irreversibly stains growing teeth and bones) Caution Myasthenia gravis may worsen, exacerbates SLE SE GI disturbance including, dysphagia/oesophageal irritation Interaction Decreased absorption with dairy products, decreases effects of oral contraceptive pill, mildly increases effects of warfarin.

Pabrinex^® See thiamine.

Pantoprazole Proton pump inhibitor. Dose 20–80mg/24h PO; IV preparation available for endoscopically proven bleeding ulcers (consult BNF/local guidelines) Indication Prophylaxis and treatment of peptic ulcers, GORD, H. pylori eradication Caution Hepatic impairment (max 20mg/24h), renal impairment (max oral dose 40mg/24h), can mask gastric cancer SE GI disturbance, headache, dizziness Interaction Proton pump inhibitors may reduce effectiveness of clopidogrel.

Paracetamol Simple analgesic. Dose 0.5–1g/4–6h PO/IV (max 4g/24h in divided doses) Indication Pain; mild to moderate, pyrexia Caution Alcohol dependence, hepatic impairment SE Rare; rash, hypoglycaemia, blood disorders, hepatic impairment Interaction Prolonged use can potentiate warfarin.

Paroxetine Selective serotonin re-uptake inhibitor. Dose 20–40mg/24h PO (max 50–60/24h) Indication Major depression, obsessive-compulsive disorder, panic disorder, post-traumatic stress disorder Caution Pregnancy, epilepsy, cardiac disease, DM SE GI disturbance, anorexia, weight loss, ↓Na⁺, agitation; increased incidence of antimuscarinic, extrapyramidal and withdrawal effects compared with fluoxetine.

Penicillin G Beta-lactam. See benzylpenicillin.

Penicillin V Beta-lactam. See phenoxymethylpenicillin.

Pentasa^® Aminosalicylate. See mesalazine.

Peppermint oil Antispasmodic. Dose 1–2 capsules/8h PO before meals Indication Abdominal colic and distension especially in IBS Caution Sensitivity to menthol SE Heartburn, perianal irritation.

Perindopril See ACEi.

Pethidine Opioid. Dose 25–100mg/4h SC/IM; 25–50mg/4h slow IV Indication Pain; moderate to severe, obstetric, post-op CI Acute respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients Caution Pregnancy (especially delivery), COPD, asthma, arrhythmias, renal impairment, hepatic impairment SE N+V, less constipation than morphine, respiratory depression, dry mouth.

Phenobarbital Barbiturate. Dose Epilepsy (not 1st line) 60–180mg/24h PO at night; Status epilepticus 10mg/kg at max 100mg/min (max 1g) IV (see BNF) Indication Epilepsy, status epilepticus CI Pregnancy, breastfeeding, hepatic impairment Caution Renal impairment, acute porphyria SE Respiratory depression, hypotension, sedation.

Monitoring phenobarbital

Trough 60–180micromol/L (15–40mg/L) ► Toxic >180micromol/L (>40mg/L)

Phenoxymethylpenicillin (penicillin V) Beta-lactam. Dose 0.5–1g/6h PO Indication Oral infections, post-splenectomy (prophylaxis) CI Penicillin allergy Caution History of allergy SE diarrhoea Interaction Decrease effects of oral contraceptive pill, allopurinol increases risk of rash.

Phenytoin Antiepileptic. Dose Epilepsy 3–4mg/kg/24h PO increased gradually as necessary; Status epilepticus loading dose = 20mg/kg IV at no more than 50mg/min with ECG monitoring, maintenance = 100mg/6–8h thereafter IV (see BNF); monitor level (see ‘Monitoring phenytoin’) Indication Epilepsy, status epilepticus CI Pregnancy, breastfeeding, sinus hypotension Caution Hepatic impairment, avoid abrupt withdrawal, acute porphyria; monitor blood count SE Drowsiness, cerebellar effects, hypotension, arrhythmias, purple glove syndrome, blood disorders; Chronic use coarse facies, hirsutism, gum hypertrophy Info As drug highly protein bound, may need to adjust monitored levels for low albumin (consult pharmacist).

Monitoring phenytoin

Trough 40–80micromol/L (10–20mg/L) ► Toxic >80micromol/L (>20mg/L) ► Signs of toxicity Ataxia, nystagmus, dysarthria, diplopia

Phosphate enema See laxatives.

Phytomenadione Vitamin K₁. Dose 1–10mg/STAT PO/IV depending upon indication—consult BNF and/or d/w haematologist Indication Bleeding and/or over-anticoagulation with warfarin Caution Pregnancy, give IV slowly.

Picolax^® See laxatives.

Piperacillin with tazobactam Beta-lactam with tazobactam. Dose 4.5g/6–8h IV Indication Severe infection, infection in neutropenic patients (in combination with aminoglycoside) CI Penicillin allergy Caution Pregnancy, breastfeeding, renal impairment, history of penicillin allergy SE Diarrhoea.

Piriton^® Antihistamine (H₁ antagonist). See chlorphenamine.

Plavix^® Antiplatelet. See clopidogrel.

Potassium oral supplement Potassium salt. Dose Potassium chloride: 2–4g/24h PO (two tablets/8–12h) Indication Potassium loss CI Serum potassium >5mmol/L Caution Renal impairment, elderly, intestinal strictures, history of peptic ulcer SE GI disturbance, upper GI ulceration Info Check serum Mg²⁺ as this is also likely to be low in ↓K⁺.

Pravastatin HMG CoA reductase inhibitor. See statin.

Prednisolone Corticosteroid. Dose Initially 10–20mg/24h mane PO though often 30–40mg/24 PO in severe disease (up to 60mg/24h); Maintenance 2.5–15mg/24h PO Indication Suppression of inflammatory and allergic disorders (eg IBD, asthma, COPD), immunosuppression CI Systemic infection without antibiotic cover Caution Adrenal suppression SE Peptic ulceration, Cushing’s syndrome, DM, osteoporosis Interaction Duration of action decreased by rifampicin, carbamazepine, phenytoin; duration of action increased by erythromycin, ketoconazole, ciclosporin Info Consider bone and GI protection strategies when using long-term corticosteroids; p. 179.

Pregabalin Antiepileptic. Dose Epilepsy 25mg/12h PO increased every 7d by 50mg to 100–150mg/8–12h (max 600mg/24h in divided doses); Pain/anxiety 75mg/12h increased every 3–7d up to max 600mg/24h in divided doses Indication Epilepsy, neuropathic pain, generalized anxiety disorder CI Pregnancy, breastfeeding Caution Renal impairment, severe congestive heart failure, avoid abrupt withdrawal SE GI disturbance, dry mouth, dizziness, drowsiness.

Prochlorperazine Phenothiazine. See antiemetics.

Procyclidine Anticholinergic. Dose 2.5mg/8h PO increased every 3d up to max 30mg/24h in divided doses; Acute dystonia 5–10mg IM/IV Indication Parkinsonism; drug-induced extrapyramidal symptoms CI Urinary retention, glaucoma, myasthenia gravis Caution Pregnancy, breastfeeding, hepatic or renal impairment, cardiovascular disease, prostatic hyperplasia, tardive dyskinesia SE Antimuscarinic effects.

Propranolol See beta-blockers.

Protamine Heparin antagonist. Dose 1mg IV neutralizes 80–100units heparin IV in last 15min (max 50mg at rate <5mg/min); 1mg IV neutralizes 100units heparin SC (max 50mg at rate <5mg/min) Indication Heparin OD, bleeding in patient on heparin therapy Caution Risk of allergy increased post-vasectomy, or in infertile men, fish allergy SE GI disturbance, flushing, hypotension, dyspnoea Info Protamine can also be used to help reverse the effects of LMWH but it is much less effective at this than for heparin.

Prozac^® Selective serotonin re-uptake inhibitor. See fluoxetine.

Pulmicort^® Corticosteroid. See budesonide.

Quinine Plant alkaloid. Dose Nocturnal leg cramps 200–300mg/24h (nocte) PO; Treatment of malaria See BNF Indication Nocturnal leg cramps, treatment and prophylaxis of malaria CI Haemoglobinuria, myasthenia gravis, optic neuritis, tinnitus Caution Pregnancy (teratogenic in 1st trimester), breastfeeding, hepatic or renal impairment, cardiac disease (AF, conduction defects, heart block), elderly, G6PD deficiency SE Cinchonism (tinnitus, headache, hot and flushed skin, nausea, abdominal pain, rashes, visual disturbances (including temporary blindness), confusion), acute kidney injury, photosensitivity.

Ramipril See ACEi.

Ranitidine Antihistamine (H₂ antagonist). Dose 150mg/12h PO; IV preparation available (see BNF) Indication Peptic ulcers, GORD Caution Pregnancy, breastfeeding, renal impairment, acute porphyria, may mask symptoms of gastric cancer SE GI upset, confusion, fatigue.

Reteplase Plasminogen activator. See fibrinolytic.

Rifampicin Antibiotic. Dose Tuberculosis consult BNF; Meningitis prophylaxis 600mg/12h PO for 2d; Other serious infections 600mg/12h IV (usually after microbiology advice) Indication Tuberculosis, N. meningitidis/H. influenza meningitis prophylaxis, serious staphylococcal infections CI Jaundice Caution Pregnancy, hepatic or renal impairment, alcohol dependence, acute porphyria SE GI disturbance, headache, drowsiness, hepatotoxicity, turns body secretions orange Interaction Induces p450, decreases effects of warfarin.

Rivaroxaban Direct inhibitor of factor Xa. Indication and dose VTE prophylaxis after hip/knee replacement 10mg/24h for 14d for knees, 5wk for hips (start 6–10h after surgery); Treatment of DVT/PE Initially 15mg/12h for 21d; For prophylaxis of recurrent PE/DVT 20mg/24h; Prophylaxis of stroke and systemic embolism in non-valvular AF and 1 risk factor (Such as previous stroke or TIA, symptomatic heart failure, DM, HTN, or >75yr.) 20mg/24h; Prophylaxis of atherothrombotic events following ACS with elevated cardiac biomarkers (In combination with aspirin alone or aspirin and clopidogrel.) 2.5mg/12h for 12 months. Caution Avoid in patients with significant bleeding risk. Wait 6h after last dose before removing epidural catheter and wait 5h until next dose. SE Haemorrhage; abdominal pain; constipation; diarrhoea; dizziness; dyspepsia; headache; hypotension; nausea; pain in extremities; pruritus; rash; renal impairment; vomiting. Info No routine anticoagulant monitoring required (INR tests are unreliable). Take doses >10mg/24h with food. Reduce dose in renal impairment.

Rosuvastatin HMG CoA reductase inhibitor. See statin.

(r) tPA Plasminogen activator. See fibrinolytic.

Salbutamol β₂ agonist. Dose Chronic airways disease 100–200micrograms aerosol/200–400micrograms powder INH PRN (max 400–800micrograms/24h in divided doses); 2.5–5mg/4h NEB; Status asthmaticus 2.5–5mg/PRN NEB; 250micrograms/STAT (diluted to 50micrograms/mL) slow IV, followed by maintenance infusion of 3–20micrograms/min (3–24mL/h of the 50micrograms/mL solution), titrated to heart-rate Indication Asthma; chronic and acute, other reversible airway obstruction, eg COPD, ↑K⁺ Caution Cardiovascular disease, DM, hyperthyroidism SE Fine tremor, nervous tension, headache, palpitation, muscle cramps.

Salmeterol Long-acting β₂ agonist. Dose 50–100micrograms/12h INH Indication Chronic asthma, reversible airway obstruction Caution Cardiovascular disease, DM, hyperthyroidism SE Fine tremor, nervous tension, headache, palpitation, muscle cramps.

Sando-K^® Potassium salt. See potassium oral supplement.

Senna See laxatives.

Seretide^® Long-acting β₂ agonist with corticosteroid. Dose 25–50micrograms salmeterol with 50–500micrograms fluticasone/12–24h INH (depends upon inhaler device, see BNF) Indication Asthma ( p. 279) Caution Cardiovascular disease, DM, hyperthyroidism, TB SE Fine tremor, nervous tension, headache, palpitation, muscle cramps, oral candidiasis, hoarse voice, paradoxical bronchospasm (rare) Interaction See salmeterol and fluticasone.

Sertraline Selective serotonin re-uptake inhibitors. Dose 50mg/24h PO increased by 50mg increments at intervals of at least 1wk until desired effect (max 200mg/24h) Indication Depression, OCD, panic disorder CI Hepatic or renal impairment, active mania Caution Pregnancy, epilepsy, cardiac disease, DM SE GI disturbance, anorexia, weight loss Interaction MAOI within 2wk, inhibits p. 450 enzymes.

Sevredol^® Opioid. See oral morphine.

Simvastatin HMG CoA reductase inhibitor. See statin.

Slow-K^® Potassium salt. See potassium oral supplement.

Sodium valproate Antiepileptic. See valproate.

Sotalol See beta-blockers.

Spironolactone Potassium-sparing diuretic (aldosterone antagonist). Dose 100–200mg/24h PO (max 400mg/24h) Indication Oedema/ascites in cirrhosis/malignancy, nephritic syndrome, congestive heart failure CI Pregnancy, breastfeeding, hyperkalaemia, hyponatraemia, Addison’s disease Caution Renal impairment, porphyria SE GI disturbance, impotence, gynaecomastia, menstrual irregularities Interaction Increases digoxin and lithium levels; risk of ↑K⁺ when used with ACEi or AT II receptor antagonists.

Statins HMG CoA reductase inhibitor. Dose See Table 5.18 Indications Dyslipidaemias, primary and secondary prevention of cardiovascular disease (irrespective of serum cholesterol) Caution Pregnancy, breastfeeding, hypothyroidism, hepatic impairment, high alcohol intake, SE Myalgia, myositis (in severe cases rhabdomyolysis), GI disturbance, pancreatitis, altered LFTs (rarely hepatitis/jaundice) Interaction Avoid concomitant use of macrolide antibiotics and amiodarone (possible increased risk of myopathy).

Table 5.18 Statins

Atorvastatin	Dose Initially 10mg/24h PO up to max 80mg/24h PO
Fluvastatin	Dose Initially 20mg/24h PO up to max 80mg/24h PO
Pravastatin	Dose Initially 10mg/24h PO up to max 40mg/24h PO
Rosuvastatin	Dose Initially 5mg/24h PO up to max 40mg/24h PO
Simvastatin	Dose Initially 10mg/24h PO up to max 80mg/24h PO

Stemetil^® Phenothiazine. See antiemetic.

Streptokinase Plasminogen activator. See fibrinolytic.

Sulfasalazine Aminosalicylate. Dose Maintenance 500mg/6h PO; Acute 1–2g/6h PO until remission; PR preparations also available Indication Rheumatoid arthritis, ulcerative colitis, Crohn’s disease CI Sulfonamide sensitivity Caution Pregnancy, breastfeeding, renal impairment, G6DP deficiency SE GI disturbance, blood disorders, hepatotoxicity, discoloured bodily fluids.

Sulfonylureas Dose See Table 5.19 Indications Type 2 DM CI Ketoacidosis Caution Pregnancy, breastfeeding, hepatic or renal impairment, porphyria; should not be 1st-line agents in obese patients as will encourage further weight gain SE N+V, diarrhoea, constipation, hyponatraemia, hypoglycaemia, hepatic dysfunction, weight gain Info Hypoglycaemia resulting from sulfonylureas can persist for many hours and must always be treated in hospital; sulfonylureas should not be given on the day of surgery due to the risk of hypoglycaemia.

Table 5.19 Sulphonylureas

Glibenclamide	Dose 5mg (2.5–15mg) 24h PO mane Info Long acting; use cautiously in the elderly
Gliclazide	Dose 40–80mg (40–160mg) usually 24h PO mane (max 320mg) Info Medium acting
Glipizide	Dose 2.5–5mg (2.5–15mg) usually 24h PO mane (max 20mg) Info Short acting
Tolbutamide	Dose 0.5–1.5g (0.5–2g) divided throughout the day PO with meals Info Medium acting

Symbicort^® Long-acting β₂ agonist with corticosteroid. Dose 6–12micrograms formoterol with 100–400micrograms budesonide/12–24h INH (depends upon inhaler device, see BNF) Indication Asthma ( p. 279), COPD Caution Cardiovascular disease, DM, hyperthyroidism, TB SE Fine tremor, nervous tension, headache, palpitation, muscle cramps, oral candidiasis, hoarse voice, paradoxical bronchospasm (rare) Interaction See salmeterol and fluticasone.

Synacthen^® Synthetic corticotrophin (ACTH). See tetracosactide.

Tamiflu^® Antiviral. See oseltamivir.

Tamoxifen Oestrogen receptor antagonist. Dose Breast cancer 20mg/24h PO; for other indications consult BNF Indication Oestrogen receptor-positive breast cancer, anovulatory infertility CI Pregnancy Caution Breastfeeding, increased risk of thromboembolism, occasional cystic ovarian swellings in pre-menopausal women SE Hot flushes, vaginal discharge/bleeding, menstrual suppression, GI disturbance Interaction Increases effects of warfarin.

Tamsulosin α₁ antagonist. Dose 400micrograms/24h PO Indication Benign prostatic hyperplasia CI Breastfeeding, hypotension, hepatic impairment Caution Renal impairment SE Postural hypotension, headache, dizziness, urinary incontinence Interaction Increases effects of antihypertensives.

Tazocin^® Beta-lactam with tazobactam. See piperacillin.

Tegretol^® Antiepileptic. See carbamazepine.

Teicoplanin Glycopeptide antibiotic. See vancomycin.

Temazepam Benzodiazepine. Dose 10–20mg/24h PO at bedtime or preoperative; dependency common (max 4wk course) Indication Insomnia, preoperative anxiety CI Respiratory depression, sleep apnoea, unstable myasthenia gravis, hepatic impairment Caution Pregnancy, breastfeeding, history of drug abuse, respiratory disease, muscle weakness, renal impairment SE Drowsiness, confusion, muscle weakness.

Tenecteplase Plasminogen activator. See fibrinolytic.

Terbutaline β₂ agonist. Dose 500micrograms/6h INH; 5–10mg/6–12h NEB; oral preparations are also available, consult BNF Indication Asthma and other reversible airway obstruction, uterine relaxation during pregnancy Caution Cardiovascular disease, DM, hyperthyroidism SE Fine tremor, nervous tension, headache, palpitation, muscle cramps.

Tetanus vaccine and immunoglobulin p. 451.

Tetracosactide (Synacthen^®) Synthetic corticotrophin (ACTH). Dose 250micrograms IV/IM Indication Diagnosis of Addison’s disease Caution Pregnancy, breastfeeding, allergic disorders SE Cushing’s syndrome, DM, osteoporosis Info Blood should be sampled for cortisol pre-dose and again at 30min post Synacthen^® dose (consultant local guidelines).

Tetracycline Tetracycline antibiotic. Dose 250–500mg/6h PO Indication Infection, acne vulgaris CI Pregnancy, breastfeeding, renal impairment, age <12yr (irreversibly stains growing teeth and bones) Caution Myasthenia gravis may worsen, exacerbates SLE SE GI disturbance including, dysphagia/oesophageal irritation Interaction Decreased absorption with milk, decreases effects of oral contraceptive pill, mildly increases effects of warfarin.

Theophylline Methylxanthine. Dose 200–500mg/12h PO (depending upon preparation, consult BNF) Indication Severe asthma/COPD (see BTS guidelines) CI acute porphyria Caution Cardiac disease, epilepsy, hyperthyroidism, peptic ulcer disease SE Tachycardia, palpitation, GI disturbance Info Theophylline is only available as an oral preparation; aminophylline consists of theophylline and ethylenediamine which simply improves the drug’s solubility allowing IV administration.

Monitoring theophylline

► Toxic >20mg/L (>110micromol/L) ► Signs of toxicity Arrhythmia, anxiety, tremor, convulsions ( OHAM4 p. 731)

Thiamine Vitamin B₁. Dose Oral 25–100mg/24h or 200–300mg/24h PO depending on severity (consult BNF); Parenteral 2–3 pairs of ampoules/8h IV (Pabrinex^®) (consult local guidelines) Indication Nutritional deficiency, especially alcoholism Caution Reports of anaphylaxis with parenteral preparations.

Thyroxine Thyroid hormone (T₄). See levothyroxine.

Tinzaparin Low-molecular-weight heparin. Dose Depends upon indication, consult BNF Indication DVT/PE prophylaxis and treatment CI Breastfeeding, bleeding disorders, thrombocytopenia, severe hypertension, recent trauma Caution Hyperkalaemia, hepatic or renal impairment SE Haemorrhage, thrombocytopenia, hyperkalaemia Interaction NSAIDs increase bleeding risk, effects increased by GTN.

Tiotropium Antimuscarinic (anti-M3). Dose 18micrograms/24h INH; solution for inhalation also available (see BNF) Indication Maintenance treatment of COPD Caution Renal impairment, glaucoma, prostatic hypertrophy, cardiac rhythm disorders SE Minimal antimuscarinic effects.

Tirofiban Glycoprotein IIb/IIIa inhibitor. Dose Initially 400nanograms/kg/min for 30min IV; Then 100nanograms/kg/min IV for at least 48h (max 108h treatment) Indication Prevention of MI in unstable angina/NSTEMI patients CI Breastfeeding, abnormal bleeding/cerebrovascular accident within 30d, history of haemorrhagic stroke, severe hypertension, intracranial disease Caution Pregnancy, hepatic or renal impairment, increased risk of bleeding, surgery or major trauma within 3mth SE Bleeding, reversible thrombocytopenia.

Topical corticosteroids Dose Consult BNF; guidance on applying topical steroids can be found on p. 180 Indications Inflammatory conditions of the skin, eg eczema, contact dermatitis amongst others CI Untreated bacterial, fungal, or viral skin lesions, rosacea, perioral dermatitis, widespread plaque psoriasis Caution Use lowest potency agent possible (Table 5.20) for shortest duration of time to limit side effects SE Local Thinning of the skin, worsening local infection, striae and telangiectasia, acne, depigmentation, hypertrichosis; Systemic Rarely adrenal suppression, Cushing’s syndrome Info Topical steroids should only be commenced after seeking specialist advice (either following a dermatology review or after consideration by registrar). The decision to stop potent topical steroids should be taken as seriously—always be mindful of the potential for a patient to develop an Addison crisis after stopping long-term potent topical steroids.

Table 5.20 Topical corticosteroid potencies

Potency	Examples
Mild	Hydrocortisone 0.1–2.5%, Dioderm®, Mildison®, Synalar 1 in 10 dilution®
Moderately potent	Betnovate-RD®, Eumovate®, Haelan®, Modrasone®, Synalar 1 in 4 dilution®, Ultralanum Plain®
Potent	Beclometasone dipropionate 0.025%, betamethasone valerate 0.1%, Betacap®, Betesil®, Bettamousse®, Betnovate®, Cutivate®, Diprosone®, Elocon®, hydrocortisone butyrate, Locoid®, Locoid Crelo®, Metosyn®, Nerisone®, Synalar®
Very potent	Clarelux®, Dermovate®, Etrivex®, Nerisone Forte®

Tramadol Opioid. Dose 50–100mg/4h PO/IM/IV (max 600mg/24h in divided doses) Indication Pain CI Acute respiratory depression, paralytic ileus, raised ICP/head trauma, comatose patients, acute porphyria, uncontrolled epilepsy Caution Pregnancy (especially delivery), breastfeeding, COPD, asthma, arrhythmias, hepatic or renal impairment SE N+V constipation, respiratory depression, dry mouth Interaction MAOI within 2wk Info Co-prescribe laxatives if using opioids for >24h.

Trimethoprim Antibiotic. Dose Acute infection 200mg/12h PO; Prophylaxis 100mg/24h PO at night Indication Urinary tract infections CI Blood dyscrasias Caution Pregnancy, breastfeeding, renal impairment, folate deficiency SE GI disturbance, rash, hyperkalaemia Interaction Increases phenytoin levels, increases risk of arrhythmias with amiodarone.

Valproate Antiepileptic. Dose 300mg/12h PO increasing by 200mg every 3d (max 2.5g/24h in divided doses) Indication Epilepsy: all forms CI Family history of hepatic dysfunction, acute porphyria Caution Pregnancy, breastfeeding, hepatic or renal impairment, blood disorders (bleeding risk), SLE, pancreatitis SE GI disturbance, sedation, headache, cerebellar effects, hepatotoxicity, blood disorders Interaction Effects decreased by antimalarials, antidepressants, antipsychotics and antiepileptics.

Monitoring valproate

Trough 350–700micromol/L (50–100mg/L) ► Toxic >1260micromol/L (>180mg/L)

Valsartan See AT II antagonists.

Vancomycin Glycopeptide antibiotic. Dose 125mg/6h PO; 1–1.5g/12h IV; some centres use continuous infusions of vancomycin (consult local guidelines) Indication Serious Gram +ve infections: endocarditis, MRSA, antibiotic associated colitis Caution Pregnancy, breastfeeding, renal impairment, avoid rapid infusion, history of deafness, inflammatory bowel disease SE Nephrotoxicity, ototoxicity, blood disorders, rash (red man syndrome) Interaction Increased nephrotoxicity with ciclosporin, increased ototoxicity with loop diuretics.

Monitoring vancomycin

Usually before 3rd or 4th dose (check local guidelines) Trough 10–15mg/L ► Toxicity can occur within therapeutic range

Venlafaxine Serotonin and noradrenaline re-uptake inhibitor. Dose Initially 37.5mg/12h, increase if necessary at intervals of >2wks to 75mg/12h (max 375mg per 24h) Indication Major depression, generalized anxiety disorder CI Breastfeeding, high risk of cardiac arrhythmia, uncontrolled hypertension Caution Pregnancy, hepatic or renal impairment, heart disease, epilepsy, history of mania, glaucoma SE GI disturbance, hypertension, palpitation, dizziness, drowsiness Interaction MAOIs within 2wk, increased risk of bleeding with aspirin/NSAIDs, CNS toxicity with selegiline, mildly increases effects of warfarin.

Ventolin® β₂ agonist. See salbutamol.

Verapamil See Calcium-channel blockers.

Vitamin K See Phytomenadione.

Warfarin Coumarin. Dose Loading p. 422; Maintenance Typically 1–5mg/24h PO dictated by the patient’s INR (though higher doses and dosing on alternative days are not uncommon) Indication Prophylaxis of thromboembolism (atrial fibrillation, mechanical heart valves, etc), treatment of venous thrombosis or pulmonary embolism CI Pregnancy, peptic ulcers, severe hypertension, bacterial endocarditis Caution Breastfeeding, hepatic or renal impairment, conditions in which risk of bleeding is increased (eg GI bleeding, peptic ulcer, recent surgery, recent ischaemic stroke, postpartum, bacterial endocarditis), uncontrolled hypertension recent SE Haemorrhage, rash, alopecia Interaction Avoid cranberry juice (↑anticoagulant effect) Info Warfarin is available in tablets of 0.5mg (white), 1mg (brown), 3mg (blue), and 5mg (pink) but check which tablets are stocked locally.

Zolpidem Non-benzodiazepine hypnotic. Dose 10mg/24h PO at night Indication Short-term treatment of insomnia CI Breastfeeding, severe hepatic impairment, psychotic illness, neuromuscular respiratory weakness, unstable myasthenia gravis, respiratory failure, sleep apnoea Caution Pregnancy, hepatic or renal impairment, muscle weakness, history of drug abuse SE Taste disturbance, GI disturbance, headache.

Zopiclone Non-benzodiazepine hypnotic. Dose 3.75–7.5mg/24h PO at night Indication Short-term treatment of insomnia CI Breastfeeding, severe hepatic impairment, neuromuscular respiratory weakness, unstable myasthenia gravis, respiratory failure, sleep apnoea Caution Pregnancy, hepatic or renal impairment, muscle weakness, history of drug abuse SE Taste disturbance, GI disturbance, headache.

Zoton^® Proton pump inhibitor. See lansoprazole.

Zyban^® Treatment of nicotine dependence. See bupropion.

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¹ www.nrls.npsa.nhs.uk/resources/type/alerts/?entryid45=65426