Which antihypertensive agent has both alpha- and beta-blocker activities?

• A. Carvedilol (Coreg)
• B. Hydralazine (Apresoline)
• C. Minoxidil (Loniten)
• D. Spironolactone (Aldactone)

Answer: (A)

This question hinges on recognizing drugs that combine two receptor-blocking actions. Blocking alpha-1 receptors lowers vascular resistance, reducing afterload, while blocking beta-1 receptors decreases heart rate and contractility, lowering myocardial workload. Carvedilol fits this by providing nonselective beta-blockade along with alpha-1 blockade, giving both decreased peripheral vascular resistance and reduced cardiac workload. The other agents work through different mechanisms: hydralazine and minoxidil are direct vasodilators that lower blood pressure without blocking adrenergic receptors (and can trigger reflex tachycardia), while spironolactone is an aldosterone antagonist that lowers BP mainly through diuresis and potassium-sparing effects, not receptor blockade.