Which medication is a nonselective α-antagonist used for the preoperative preparation of pheochromocytoma?

Phenoxybenzamine is a nonselective α-antagonist specifically utilized in the preoperative management of pheochromocytoma, a tumor of the adrenal gland that produces excess catecholamines. This medication works by irreversibly binding to α-adrenergic receptors, leading to a long-lasting blocking effect. This is particularly effective in managing the hypertension and other symptoms caused by the excessive production of catecholamines associated with pheochromocytoma.

The use of phenoxybenzamine is preferred in this context because it effectively prevents acute hypertensive episodes during surgery by continuously blocking the α-adrenergic receptors, thus allowing for better control over blood pressure and minimizing intraoperative complications. It is important to use a long-acting agent like phenoxybenzamine for this purpose.

Other medications listed may have certain applications in managing hypertension or urinary symptoms but do not serve the same role as phenoxybenzamine in the context of pheochromocytoma preparation. For example, doxazosin and terazosin are more selective α-1 antagonists, commonly used for hypertension or urinary symptoms, while propranolol is a nonselective β-blocker typically used to manage symptoms of excess catecholamines but not as the first choice