Learn how medicines work, the way pharmacology is taught. Master the drug classes and their mechanisms of action: how a drug moves through the body (pharmacokinetics — absorption, distribution, metabolism, excretion), how it acts on receptors (agonists, antagonists, dose–response, therapeutic index), and — class by class — the main effect, the typical use, and the signature side effect, across the autonomic, cardiovascular, nervous, endocrine, and anti-infective drug groups. Each question teaches the mechanism and names the classic mix-ups. Builds on Human Biology; great for nursing, pharmacy, and pre-med review. Educational only — how drug classes work in general, NOT dosing, prescribing, or medical advice; treatment decisions belong to a qualified professional.