Learning Objective
By the end of this section, students should be able to identify common drug-induced cardiovascular adverse effects, their causative agents, and key management principles, which are high-yield for USMLE Step 1 pharmacology.
Drug-Induced Cardiovascular Reactions
| Reaction | Causal Agents | Notes / Management |
|---|---|---|
| Coronary vasospasm | Cocaine, Amphetamines, Sumatriptan, Ergot alkaloids | Acute chest pain; cocaine-induced vasospasm may cause MI; avoid β-blockers alone (risk of unopposed α-adrenergic activity) |
| Cutaneous flushing | Vancomycin, Adenosine, Niacin, Ca²⁺ channel blockers (dihydropyridines), Echinocandins, Nitrates | Vancomycin “red man syndrome” → histamine-mediated, infusion rate–dependent; manage with slower infusion and diphenhydramine |
| Dilated cardiomyopathy | Alcohol, Anthracyclines (doxorubicin, daunorubicin; prevent with dexrazoxane), Trastuzumab | Chronic drug-induced myocardial injury; monitor LVEF in anthracycline and trastuzumab therapy |
| Peripheral edema | Dihydropyridine Ca²⁺ channel blockers (e.g., amlodipine) | Usually dose-dependent; non-dihydropyridine CCBs are less likely |
| Torsades de pointes | Drugs that prolong QT interval: Methadone, Class IA & III antiarrhythmics, Macrolides, Fluoroquinolones, Antipsychotics (ziprasidone), TCAs, Ondansetron, Fluconazole | Mnemonic: “ABCDE-F” (AntiArrhythmics, antiBiotics, anti“C”ychotics, antiDepressants, antiEmetics, antiFungals); correct electrolytes (Mg²⁺, K⁺), discontinue offending agent, may require magnesium or pacing |
USMLE Step 1 Pearls
- Red man syndrome is histamine-mediated, not a true allergy.
- Cocaine + β-blocker alone → unopposed α-adrenergic vasospasm → MI risk.
- Anthracyclines → dose-dependent cardiomyopathy; dexrazoxane is protective.
- QT prolongation → Torsades; monitor ECG, correct electrolytes, avoid multiple QT-prolonging drugs.
- Mnemonic for QT-prolonging drugs: A-B-C-D-E-F.
