Pharmacology and Therapeutics
Core concepts
Pharmacology questions reward knowing mechanism, key adverse effect, and monitoring for high-yield drug classes. Master anticoagulants (heparin - aPTT, protamine reversal; warfarin - INR, vitamin K; direct oral anticoagulants), antihypertensives (ACE inhibitors causing cough and hyperkalemia; thiazides causing hypokalemia and hyperuricemia), antibiotics by mechanism (beta-lactams cell wall, macrolides 50S, fluoroquinolones DNA gyrase), and diabetes agents (metformin and lactic acidosis risk in renal failure; insulin hypoglycemia). Know autonomic pharmacology, analgesic tiers, and the classic antidotes (naloxone, flumazenil, N-acetylcysteine, glucagon for beta-blocker overdose).
Traps
Examiners test the adverse effect that mimics a new disease: ACE inhibitor cough mistaken for asthma, statin myopathy, aminoglycoside nephrotoxicity and ototoxicity, and NSAID-induced renal injury. Another trap is drug interactions - warfarin with antibiotics or amiodarone, macrolides inhibiting CYP3A4, and serotonin syndrome from combined serotonergic agents. Questions may ask which drug to avoid in pregnancy (ACE inhibitors, warfarin, isotretinoin) or in renal failure (metformin, NSAIDs, aminoglycosides). Distinguish pharmacokinetics (absorption, distribution, metabolism, elimination) from pharmacodynamics (what the drug does).
Worked rule of thumb
For any adverse-effect stem, name the mechanism first, then the effect. Example: a patient on an ACE inhibitor develops a dry cough and hyperkalemia - the mechanism is bradykinin accumulation and reduced aldosterone; the answer is to switch to an angiotensin receptor blocker, which does not increase bradykinin. For antidote questions, pair the toxin with the receptor or pathway: opioid with naloxone, benzodiazepine with flumazenil, acetaminophen with N-acetylcysteine, warfarin with vitamin K, heparin with protamine.