What drug class is used preoperatively to prevent catecholamine surge during pheochromocytoma surgery?

• A. Beta-blocker
• B. Alpha-adrenergic blocker
• C. ACE inhibitor
• D. Calcium channel blocker

Answer: (B)

During pheochromocytoma surgery, manipulation of the tumor can release large amounts of catecholamines, causing dangerous spikes in blood pressure. The best way to prevent this surge is by blocking alpha-adrenergic receptors, especially the alpha-1 receptors on blood vessels. When these receptors are blocked, catecholamine-induced vasoconstriction is markedly reduced, so blood pressure stays more stable during tumor handling.

This alpha blockade is typically started days to weeks before surgery to allow the vessels to relax and for blood volume to normalize, because chronic catecholamine excess often leaves the circulating volume relatively low. After adequate alpha blockade, a beta blocker may be added if there’s still tachycardia or arrhythmia, but only once alpha blockade is in place. Using a beta blocker alone would let unopposed alpha activity raise blood pressure during the procedure, which is dangerous.

ACE inhibitors or calcium channel blockers don’t address the acute catecholamine surge as effectively as alpha blockade and aren’t the primary preventive strategy in this setting.