A 28-year-old man presents with severe chest pain shortly after using cocaine. ECG shows ST elevation in leads V1 to V3 and he is agitated and hypertensive. Along with benzodiazepines and sublingual nitroglycerin, which additional agent is CONTRAINDICATED in his management?
- A Aspirin 300 mg orally
- B Propranolol intravenously ✓
- C Phentolamine intravenously for refractory hypertension
- D Morphine for persistent pain
Correct answer: B. Propranolol intravenously
Explanation
Cocaine causes alpha-adrenergic mediated coronary vasospasm and increased myocardial oxygen demand. Propranolol blocks beta-2 mediated vasodilation, leaving alpha vasoconstriction unopposed, which worsens spasm, raises blood pressure, and can extend the infarct, so beta-blockers are contraindicated in cocaine-associated ischaemia. Benzodiazepines reduce sympathetic tone, nitrates reverse spasm, and phentolamine, a pure alpha antagonist, is recommended for hypertension unresponsive to these measures.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
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