3.1 Drug Classifications and Naming Conventions

Quick Answer: Drugs have three names: chemical (scientific formula), generic (nonproprietary), and brand (trademarked). Drug suffixes help identify classes (e.g., -olol for beta-blockers). Generic drugs must be bioequivalent to brand names and are listed in the FDA Orange Book.

The Three Types of Drug Names

Every medication has three distinct names that identify it:

Key Point: Chemical names are rarely used in practice. Pharmacy technicians primarily work with generic and brand names.

Drug Suffixes (Stems) for Identification

Drug suffixes (or "stems") help identify which class a medication belongs to. This is critical for recognizing drug categories.

Common Drug Suffixes

Therapeutic vs. Pharmacologic Classification

Example: Lisinopril

• Therapeutic class: Antihypertensive (treats high blood pressure)
• Pharmacologic class: ACE inhibitor (blocks angiotensin-converting enzyme)

Generic vs. Brand Name Medications

Key Differences

FDA Orange Book

The FDA Orange Book (Approved Drug Products with Therapeutic Equivalence Evaluations) lists:

Exam Tip: Know common drug suffixes and that A-rated generics are considered substitutable for brand-name drugs.

Narrow Therapeutic Index (NTI) Drugs

NTI drugs have a small difference between therapeutic and toxic doses. Generic substitution may be more closely regulated for these medications.

---

Dosage Forms and Routes of Administration

The blueprint (Domain 3A) requires you to differentiate dosage forms and routes. The form determines how a drug is delivered; the route determines where it enters the body.

Exam Tip: IV gives 100% bioavailability with no first-pass metabolism. SL and rectal routes also bypass much first-pass metabolism, which is why nitroglycerin is given sublingually.

---

Common Drug-Class Suffixes and Abbreviations

Recognizing stems lets you classify an unfamiliar drug. The blueprint lists class abbreviations (NSAID, SSRI, ARB, ACE) as testable knowledge.

---

OTC and Behind-the-Counter (BTC) Distinctions

The blueprint distinguishes prescription, OTC, and behind-the-counter (BTC) products. BTC items (such as pseudoephedrine) require no prescription but are kept behind the counter with sale restrictions and logging. The technician must match common OTC and BTC products to their indications and direct any clinical questions to the pharmacist.

Worked Example: A drug ending in "-sartan" with no prescription on file is an ARB (e.g., losartan) used for hypertension; "-statin" indicates a cholesterol-lowering agent. Using the suffix lets you classify and route the question correctly.

Therapeutic Class vs Pharmacologic Class

The blueprint asks you to differentiate therapeutic classes. A therapeutic class groups drugs by what condition they treat (e.g., antihypertensives), while a pharmacologic class groups them by mechanism (e.g., ACE inhibitors). One therapeutic class can contain several pharmacologic classes.

Exam Tip: A question naming a disease (e.g., "used for hypertension") is asking for the therapeutic class; a question naming a stem or mechanism (e.g., "-pril") is asking for the pharmacologic class.