What is the first medication that should be administered for a pheochromocytoma?

In the management of pheochromocytoma, the first medication that should be administered is an alpha-blocker. Pheochromocytomas are tumors that secrete catecholamines, leading to episodes of hypertension, tachycardia, and other cardiovascular symptoms.

Alpha-blockers work by inhibiting the action of catecholamines on alpha-adrenergic receptors, which helps to reduce vascular resistance and lower blood pressure effectively. This pharmacologic approach is critical, as it addresses the underlying cause of hypertension in patients with pheochromocytoma.

Administering beta-blockers before adequate alpha-blockade is contraindicated, as it can lead to unopposed alpha-adrenergic receptor stimulation, potentially worsening hypertension and causing other serious complications. Similarly, other medications like calcium channel blockers and ACE inhibitors do not specifically target the excessive catecholamine effect, and their roles in the acute management of pheochromocytoma are not as prioritized as those of an alpha-blocker.