Which of the following is a beta-blocker medication?

• A. Prazosin
• B. Doxazosin
• C. Propranolol
• D. Terazosin

Answer: (C)

Beta-blockers dampen sympathetic activity by blocking beta-adrenergic receptors, mainly reducing heart rate and contractility to lower blood pressure. Propranolol is a non-selective beta-blocker because it blocks both beta-1 receptors in the heart and beta-2 receptors in other tissues like the lungs. The other drugs shown are alpha-1 blockers; they work by preventing alpha-1 receptor–mediated vasoconstriction, causing vasodilation and lowering blood pressure through a different mechanism, so they’re not beta-blockers. Propranolol’s non-selective action also means bronchial effects can occur in some people, unlike beta-1 selective agents.