Which medication class is used preoperatively to control blood pressure in pheochromocytoma?

Which medication class is used preoperatively to control blood pressure in pheochromocytoma?

• A. Phenoxybenzamine
• B. Nifedipine
• C. Propranolol
• D. Hydralazine

Answer: (A)

Blocking alpha-adrenergic effects before surgery is essential because pheochromocytoma releases大量 catecholamines that cause severe vasoconstriction and hypertension during tumor manipulation. Phenoxybenzamine is an irreversible alpha-adrenergic blocker that inhibits both alpha-1 and alpha-2 receptors, providing long-lasting reduction of vascular tone and stabilizing blood pressure preoperatively. This alpha blockade also allows the patient’s intravascular volume to expand, decreasing the risk of post-tumor-resection hypotension. After adequate alpha blockade is established, beta-blockade may be added if tachycardia persists, but never before alpha blockade, to avoid unopposed alpha stimulation and a spike in blood pressure. The other medications don’t address the catecholamine-driven vasoconstriction as effectively, or can worsen the situation if used alone. So the preoperative drug class of choice is phenoxybenzamine.

Blocking alpha-adrenergic effects before surgery is essential because pheochromocytoma releases大量 catecholamines that cause severe vasoconstriction and hypertension during tumor manipulation. Phenoxybenzamine is an irreversible alpha-adrenergic blocker that inhibits both alpha-1 and alpha-2 receptors, providing long-lasting reduction of vascular tone and stabilizing blood pressure preoperatively. This alpha blockade also allows the patient’s intravascular volume to expand, decreasing the risk of post-tumor-resection hypotension. After adequate alpha blockade is established, beta-blockade may be added if tachycardia persists, but never before alpha blockade, to avoid unopposed alpha stimulation and a spike in blood pressure. The other medications don’t address the catecholamine-driven vasoconstriction as effectively, or can worsen the situation if used alone. So the preoperative drug class of choice is phenoxybenzamine.