Pharmacologic agents in the management of pheochromocytoma

Medical management of pheochromocytoma involves the use of many therapeutic agents. Phenoxybenzamine HCl (Dibenzyline), an alpha-adrenergic blocking agent, at 40 to 80 mg per day can control the disease in most patients. Use of this drug up to the time of operation is controversial. Beta-adrenergic receptor blockade with propranolol is indicated only after adequate alpha-adrenergic blockade in patients with tachycardia and catecholamine-induced arrhythmias. Alpha-methylparatyrosine (Metyrosine), which decreases catecholamine synthesis, is a new drug recently released for the treatment of pheochromocytoma when surgery is contraindicated or in cases of malignant pheochromocytoma. The use of a combination of anesthetic agents, such as nitrous oxide, thiopental, narcotics, and enflurane, ensures smooth induction of anesthesia in most cases. Careful and prompt control of hypertensive crises with sodium nitroprusside and of arrhythmias with propranolol and lidocaine are critical to the success of surgery.