What is the primary action of beta blockers?

What is the primary action of beta blockers?

• A. Block beta adrenergic receptors, reducing heart rate, contractility, and blood pressure
• B. Increase heart rate and blood pressure
• C. Block calcium entry
• D. Block angiotensin II

Answer: (C)

Beta blockers work by blocking beta-adrenergic receptors, which blunts the sympathetic signals that normally raise heart rate and contractility. By occupying these receptors, they slow the heart (negative chronotropy), reduce the force of contraction (negative inotropy), and slow conduction through the AV node, lowering the heart’s workload. They also decrease renin release from the kidney, which helps lower blood pressure. This action is different from blocking calcium entry (that’s calcium channel blockers) or blocking angiotensin II (that’s the role of ACE inhibitors or ARBs). They don’t increase heart rate or blood pressure; they produce the opposite effects when used to treat hypertension or tachyarrhythmias.

Beta blockers work by blocking beta-adrenergic receptors, which blunts the sympathetic signals that normally raise heart rate and contractility. By occupying these receptors, they slow the heart (negative chronotropy), reduce the force of contraction (negative inotropy), and slow conduction through the AV node, lowering the heart’s workload. They also decrease renin release from the kidney, which helps lower blood pressure. This action is different from blocking calcium entry (that’s calcium channel blockers) or blocking angiotensin II (that’s the role of ACE inhibitors or ARBs). They don’t increase heart rate or blood pressure; they produce the opposite effects when used to treat hypertension or tachyarrhythmias.