If pheochromocytoma is suspected, which drug is preferred for managing hypertensive crises?

When managing hypertensive crises in the context of pheochromocytoma, phentolamine is preferred due to its mechanism of action as a non-selective alpha-adrenergic antagonist. Pheochromocytomas secrete excess catecholamines, which leads to elevated blood pressure and significant hypertension episodes. Phentolamine effectively blocks the effects of these catecholamines at alpha receptors, leading to vasodilation and a reduction in blood pressure.

Using phentolamine is crucial in this situation because it not only lowers the blood pressure but also counteracts the vasoconstrictive effects of the catecholamines produced by the tumor. This helps in managing both the hypertensive crises and the associated symptoms effectively.

While other agents, like labetalol, also have antihypertensive properties, they may not be as effective in this specific scenario involving pheochromocytoma, since they have both alpha- and beta-blocking effects, but do not preferentially address the alpha-mediated hypertension as directly as phentolamine. Hence, phentolamine remains the drug of choice for acute management in this condition.