D

Diuretics

USES

Thiazides: Management of edema resulting from a number of causes (e.g., HF, hepatic cirrhosis); hypertension either alone or in combination with other antihypertensives.

Loop: Management of edema associated with HF, cirrhosis of the liver, and renal disease. Furosemide used in treatment of hypertension alone or in combination with other antihypertensives.

Potassium-sparing: Adjunctive treatment with thiazides, loop diuretics in treatment of HF and hypertension.

ACTION

Increase the excretion of water/sodium and other electrolytes via the kidneys. Exact mechanism of antihypertensive effect unknown; may be due to reduced plasma volume or decreased peripheral vascular resistance. Subclassifications of diuretics are based on their mechanism and site of action.

Thiazides: Act at cortical diluting segment of nephron, block reabsorption of Na, Cl, and water; promote excretion of Na, Cl, K, and water. Loop: Act primarily at the thick ascending limb of Henle’s loop to inhibit Na, Cl, and water absorption.

Potassium-sparing: Spironolactone blocks aldosterone action on distal nephron (causes K retention, Na excretion). Triamterene, amiloride act on distal nephron, decreasing Na reuptake, reducing K secretion.

DIURETICS

Name	Availability	Dosage Range	Side Effects
Thiazide, Thiazide-related
Chlorothiazide (Diuril)	T: 250 mg, 500 mg S: 250 mg/5 ml I: 500 mg	Edema: 500–1,000 mg 1–2 times/day HTN: 500–2,000 mg/day in 1–2 divided doses	Confusion, fatigue, muscle cramps, abdominal discomfort
Chlorthalidone	Hygroton: 25 mg, 50 mg, 100 mg	Edema: Initially, 50–100 mg once daily or 100 mg every other day. Maximum: 200 mg/day	Same as chlorothiazide
Hydrochlorothiazide	T: 12.5 mg, 25 mg, 50 mg C: 12.5 mg	Edema: 25–100 mg/day in 1–2 divided doses HTN: Initially, 12.5–25 mg once daily. May increase up to 50 mg/day in 1 or 2 divided doses	Orthostatic hypotension, photosensitivity, hypokalemia, anorexia, epigastric distress, increased blood glucose
Indapamide (Lozol)	T: 1.25 mg, 2.5 mg	Edema: Initially, 2.5 mg/day. May increase after 1 wk to 5 mg/day HTN: Initially, 2.5 mg/day. May increase q4wks to 2.5 mg, then to 5 mg/day	Loss of appetite, diarrhea, headaches, dizziness, light-headedness, insomnia, upset stomach
Metolazone (Zaroxolyn)	T: 2.5 mg, 5 mg, 10 mg	Edema: 2.5–20 mg once daily HTN: 2.5–5 mg once daily	Orthostatic hypotension, dizziness, hypokalemia, nausea, diarrhea, abdominal pain
Loop
Bumetanide (Bumex)	T: 0.5 mg, 1 mg, 2 mg I: 0.25 mg/ml	Edema: Initially, 0.5–2 mg/dose 1–2 times/day. Maximum: 10 mg/day	Orthostatic hypotension, cramps or pain, hypokalemia (dry mouth, fatigue, muscle cramps), blurred vision, headaches
Furosemide (Lasix)	T: 20 mg, 40 mg, 80 mg OS: 10 mg/ml, 40 mg/5 ml I: 10 mg/ml	HTN: 20–80 mg/day in 2 divided doses Edema: PO: 20–80 mg/dose. May increase by 20–40 mg/dose up to 600 mg/day. IV: 20–40 mg/dose. May increase by 20 mg/dose. Maximum: 200 mg/dose	Orthostatic hypotension, cramps or pain, hypokalemia (dry mouth, fatigue, muscle cramps), blurred vision, headaches
Torsemide (Demadex)	T: 5 mg, 10 mg, 20 mg, 100 mg I: 10 mg/ml	Edema: 10–200 mg/day HTN: Initially, 5 mg/day. May increase after 4–6 wks to 10 mg/day	Constipation, dizziness, upset stomach, headache, hypokalemia (dry mouth, fatigue, muscle cramps)
Potassium-sparing
Amiloride (Midamor)	T: 5 mg	HF/Edema: Initially, 5 mg/day. May increase to 10 mg/day	Hyperkalemia, nausea, abdominal pain, diarrhea
Eplerenone (Inspra)	T: 25 mg, 50 mg	HF: Initially, 25 mg/day, titrate to 50 mg once daily HTN: Initially, 50 mg/day. May increase to 50 mg 2 times/day	Hyperkalemia, hypertriglyceridemia
Spironolactone (Aldactone)	T: 25 mg, 50 mg, 100 mg	Edema: 25–200 mg/day in 1 or 2 divided doses HTN: 50–100 mg/day in 1 or 2 divided doses Hypokalemia: 25–100 mg/day HF: Initially, 12.5–25 mg once daily. Maximum: 50 mg/day	Hyperkalemia, nausea, vomiting, abdominal cramps, diarrhea
Triamterene (Dyrenium)	C: 50 mg, 100 mg	Edema, HTN: 100–300 mg/day in 1–2 divided doses	Same as amiloride

C, Capsules; HF, heart failure; HTN, hypertension; I, injection; OS, oral solution; S, suspension; T, tablets.