Drug Classifications

Copyright © 2011 F.A. Davis Company

Davis’s Drug Guide for Nurses, 12th Edition

Understanding Drug

Classifications



Drug Classifications

Drugs can be classified by their therapeutic

use (e.g., antidepressants) or by their

pharmacologic profile (e.g., selective

serotonin reuptake inhibitors).



Drug Classifications (Cont’d)

Most texts use a combination of therapeutic and pharmaceutical classifications

Healthcare workers use both terms when discussing medications

Other methods of classification are used for various purposes

For example, the Schedule of Controlled Substances that classifies drugs by risk for abuse



Therapeutic Classifications Therapeutic classes are broad categories based on

therapeutic intent

Antianginals, sedatives, and analgesics are examples of

therapeutic classes

Therapeutic classes include several pharmacologic

classes

The therapeutic class antihypertensives has at least 13

pharmacologic classes



Therapeutic Classifications (Cont’d)

Drugs grouped by therapeutic class work in very different ways

They are not chemically similar

They have different mechanisms of action

Therapeutic class is useful when speaking of drugs in a general way

“Antihypertensive drugs save lives”

“You will need antihypertensive medication”



Pharmacologic Classifications

Pharmacologic classification is based on

mechanism of action and includes only those

drugs that have the same or similar

mechanism of action

For example, “angiotensin-converting enzyme

inhibitors” (ACE inhibitors) tell you exactly how

the drugs works—they inhibit the enzyme that

converts angiotensin I to angiotensin II



Pharmacologic Classifications (Cont’d)

Pharmacologic classifications describe a drug’s

properties in a specific way

Pharmacologic class is necessary when

determining treatment; a nurse might say

“An ACE inhibitor is more desirable than a beta

blocker”

“Your heart won’t race as much because the

beta blocker prevents beta-adrenergic

receptors in the heart from being stimulated”



Clues to Pharmacologic Class

Generic names of drugs in the same

pharmacologic class often have the same

suffix

Beta blockers, the pharmacologic class of

medications in the therapeutic class of

antihypertensives, end in “-olol”



Clues to Pharmacologic Class (Cont’d)

Pharmacologic Class Identifying Suffix

benzodiazepines “-epam” (e.g., diazepam)

5-HT3 antagonists “-setron” (e.g., ondansetron)

HMG-CoA reductase

inhibitors

“-statin” (e.g., rosuvastatin)

Monoclonal antibodies “-mab” (e.g., rituximab)



Drugs in a Pharmacologic Class

Have Similar Attributes

Indications

Mechanism of action

Contraindications and precautions

Interactions

Adverse reactions and side effects

These attributes are similar or identical in a pharmacologic class; if you know about one drug in a class, you will have some knowledge of other drugs in the class



Drugs in a Pharmacologic Class

May Differ

Dosages

Time action profile

Availability



ACE Inhibitors: An Example of a

Pharmacological Class of Drugs

ACE Inhibitors:

Includes at least 10

individual drugs (right)

All end in “-pril”

Commonly prescribed

drugs

benazepril moexipril

captopril perindopril

enalapril quinapril

fosinopril ramipril

lisinopril trandolapril



Indication and Action

of ACE Inhibitors Indications

Alone or with other agents in the management of hypertension

Actions

ACE inhibitors block the conversion of angiotensin I to the vasoconstrictor angiotensin II

ACE inactivates the vasodilator bradykinin and other vasodilatory prostaglandins

ACE inhibitors increase plasma renin levels and reduce aldosterone levels; net result: systemic vasodilation



Therapeutic Effects

of ACE Inhibitors

Lowering of blood pressure in hypertensive patients

Decreased afterload in patients with CHF

Decreased development of overt heart failure

Increased survival after MI (selected agents only)

Decreased progression of diabetic nephropathy (captopril only)



Side Effects of ACE Inhibitors

CNS: dizziness, fatigue, headache, insomnia, weakness

Resp: cough, eosinophilic pneumonitis

CV: hypotension, angina pectoris, tachycardia

GI: taste disturbances, anorexia, diarrhea, hepatotoxicity (rare), nausea

GU: proteinuria, impotence, renal failure

Derm: rashes

F and E: hyperkalemia

Hemat: AGRANULOCYTOSIS, NEUTROPENIA (CAPTOPRIL ONLY) Misc: ANGIOEDEMA, fever

Note: CAPITALS indicate life-threatening effects; underlines indicate most frequent



Nursing Care of Patients

on ACE Inhibitors Hypertension

Monitor frequency of prescription refills to determine

adherence

Monitor blood pressure and pulse frequently during initial

dose adjustment and periodically during therapy; notify

healthcare professional of significant changes

CHF

Monitor weight and assess patient routinely for resolution

of fluid overload (peripheral edema, rales/crackles,

dyspnea, weight gain, jugular venous distention)



Patient Safety

Always check other sources if you are uncertain about a medication’s

Use

Effect

Side effects

Dosage

Route of administration

Monitoring criteria

Any other parameter of safe and responsible medication

administration

Documents

Drug Classifications