In treating emergency hypertension, which medication is least appropriate for a patient with suspected pheochromocytoma?

In the context of suspected pheochromocytoma, the most critical concern is the excess production of catecholamines (such as epinephrine and norepinephrine) due to the tumor. These catecholamines lead to severe hypertension and other cardiovascular complications.

When treating emergency hypertension in such patients, the choice of medication is crucial. Beta-adrenergic receptor blockers can exacerbate the condition if administered without first using an alpha-adrenergic blocker. This is because blocking beta receptors can lead to unopposed alpha-adrenergic activity, potentially worsening hypertension and causing a range of cardiovascular issues.

On the other hand, calcium channel blockers can be effective in managing hypertension by causing vasodilation, while nitroprusside is a fast-acting vasodilator often used in hypertensive emergencies. Antihistamines generally are not relevant in the management of hypertension and would not be the first choice but do not have the same potential for exacerbating the condition as beta blockers.

Therefore, beta-adrenergic blockers are considered least appropriate for patients with suspected pheochromocytoma due to their potential to worsen hypertensive episodes caused by the excessive catecholamines.