Which agent exemplifies an alpha-adrenergic blocker used preoperatively for pheochromocytoma?

• A. Metformin
• B. Phenoxybenzamine
• C. Lisinopril
• D. Propranolol

Answer: (B)

Blocking alpha-adrenergic receptors before pheochromocytoma surgery is crucial to prevent dangerous blood pressure spikes when the tumor is manipulated. Phenoxybenzamine exemplifies an alpha-adrenergic blocker used preoperatively because it irreversibly blocks both alpha-1 and alpha-2 receptors, providing long-lasting control of hypertension during the perioperative period. Metformin is an antidiabetic drug, not used for alpha blockade. Lisinopril is an ACE inhibitor and does not target alpha receptors. Propranolol is a beta-blocker; using it without prior alpha blockade can lead to unopposed alpha stimulation and severe hypertension, so it’s not the agent of choice for preoperative management in this setting. After adequate alpha blockade, beta-blockade may be added if needed to control tachycardia.