🏥 USMLE Exam Prep

Beta-blockers primarily act by:

A Increasing heart rate
B Blocking beta-adrenergic receptors, reducing heart rate, contractility, and blood pressure
C Increasing blood pressure
D Dilating bronchioles

✓ Correct Answer: Option B

Beta-blockers: antagonize beta-1 (cardiac) receptors → decreased HR, contractility, and AV conduction. Non-selective also block beta-2 (bronchial smooth muscle) → contraindicated in asthma.

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