2 Pharmacology

Learning Objectives

• Describe medication regulation in the United States and the schedule system.
• Differentiate between pharmacodynamics and pharmacokinetics.
  
• Explain how to initiate an intravenous line.
  
• Identify indications for initiating an intravenous line. 
  

Understanding pharmacology is paramount to the paramedic’s success. Dozens of medications are available that could remedy a patient’s condition and improve his or her condition long before arriving at the hospital.

Medication Regulation

In the 20th century, major laws affecting medication regulation in the United States were passed.

Table 2.1 Major U.S. Laws Regulating Medications

Year	Title of Regulation	Description
1906	Pure Food and Drug Act	Prohibited altering or mislabeling medications
1909	Opium Exclusion Act	Prohibited the importation of opium
1914	Harrison Narcotic Act	Regulated and taxed the manufacture and sale of opiates and cocaine products
1938	Food, Drug, and Cosmetic Act	Gave authority to the US Food and Drug Administration to oversee the safety of food, drugs, and cosmetics
1970	Comprehensive Drug Abuse Prevention and Control Act	Classified potentially abused medications into 1 of 5 schedules, which included security, record keeping, and dispensing requirements

The Comprehensive Drug Abuse Prevention and Control Act led to the scheduling system (Table 2.2) that classifies all medications with a potential for abuse. 

Table 2.2 Schedule System for Controlled Substances

Schedule	Medication Example	Description
I	Marijuana, LSD (lysergic acid diethylamide), heroin	No medical purpose; great potential for psychological and physical addiction
II	Oxycodone, methamphetamines, meperidine, fentanyl, morphine	Drugs with a high potential for abuse but less than Schedule I. Continued use could lead to psychological and physical addiction. Contain <15 mg hydrocodone per dosage unit.
III	Ketamine, steroids, acetaminophen with codeine	Drugs with moderate to low potential for psychological and physical addiction, less than Schedule II. Drugs have <90 mg codeine per dosage unit.
IV	Alprazolam, lorazepam, diazepam, zolpidem	Potential for abuse and any type of addiction
V	Narcotic cough medications, pregabalin	Lowest risk for abuse or addiction; generally for antidiarrheal, antitussive, or analgesic purposes

Sources, Forms, and Names

Medications are derived from multiple different sources beyond synthetic preparation in a laboratory. Medications such as atropine, digoxin, and morphine come from plant sources. Heparin and insulin are most commonly produced in and collected from animals. Many antibiotics are produced from microorganisms such as bacteria and molds. Minerals are essential to our diet and can be mined from the earth. Regardless of the source, however, by the time they reach the consumer, they have been put under rigorous quality control measures to ensure what the label says is what the patient gets.

Medications also can be delivered to the patient in a multitude of forms, which are as follows:

• Tablet: powder compressed into a solid to be swallowed
• Capsule: powder or gel surrounded with a gelatin shell
  
• Suspension: water-insoluble powder suspended in a thick sugary liquid that separates on standing; shaking is required to achieve the desired dose 
  
• Solution: medication dissolved in another liquid, usually water 
  
• Metered dose inhaler: liquid or finely powdered solid in a pressurized canister for inhalation
  
• Topical: applied to skin for treatment or moisturization of skin
  
• Transdermal/transcutaneous: medication applied to and absorbed through the skin for absorption into the bloodstream; often comes as a patch, such as a nicotine patch
  
• Suppository: medication contained within a greasy/waxy substance that melts in the body to deliver the medication; often inserted into rectum
  

Medications can be referred to by any of 3 names. Depending on the medication being requested, the typical person may use either the generic or trade name but never the chemical name.

• Brand or Trade Name. Name given to the same medication by the manufacturer and approved by the Food and Drug Administration (e.g., Amidate).
  
• Generic Name. Name approved by the US Adopted Names Council and the World Health Organization to minimize medication name duplication. The original developer of a drug frequently suggests this name (e.g., etomidate).
  
• Chemical Name. Long name used by organic chemists to systematically name a structure (e.g., ethyl 3-[(1R)-1-phenylethyl]imidazole-5-caboxylate).
  

Medication Terms

The following terms are used to describe medications:

• Indications. Why a drug is given—the symptoms it is used to treat.
• Contraindications. Reasons to not give a medication. There may be relative contraindications when a medication should be avoided in favor of another medication but may be given in extreme or emergent circumstances. Absolute contraindications are reasons the drug should never be given at any time, regardless of the circumstance.
• Adverse Reactions or Side Effects. These are nontherapeutic effects that a medication has on the body. They are not desired and often can be severe enough for a person to stop taking the medication. Side effects range from annoying or bothersome to dangerous or life threatening. A patient may or may not experience 1 or all of a drug’s listed side effects.
• Idiosyncratic Effects. Specific unexpected, nontherapeutic reactions of a patient to a medication. Although side effects are typically predictable and listed on the label, untoward effects are anything but predictable. They are completely unique or so rare as not to have been experienced in great enough quantity to be listed among possible side effects.
  
• Interactions. When patients take >1 medication, care must be taken to avoid medication interactions. For example, another drug may potentiate, or increase, the effects of a medication that is being administered to treat a particular issue, potentially to the point of toxicity. One medication, or food item, may inhibit or negate the effects of another. A classic example of this is grapefruit juice enhancing the absorption of certain statin medications that are used to treat high cholesterol, which, in turn, has caused patients to experience more side effects.
  

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