A 38-year-old man recently diagnosed with pheochromocytoma c

[sameer]

A 38-year-old man recently diagnosed with pheochromocytoma comes to the office for medical evaluation in anticipation of surgery. On physical examination, his blood pressure is 190/105 mm Hg. The remainder of the examination is unremarkable.

Therapy with which of the following is indicated in preparation for surgery in this patient?

A A calcium-channel blocker
B Phenoxybenzamine
C Labetalol
D Atenolol
E Hydrochlorothiazide

[sameer]

(Answer = B)
Key Points

* Patients with pheochromocytoma should receive an α-blocker 2 weeks before surgery.
* β-Blockade in the absence of α-blockade is contraindicated in patients with pheochromocytoma and may lead to hypertensive crisis.

Patients with pheochromocytoma should be treated with α-blockade therapy for at least 2 weeks before surgery. Phenoxybenzamine provides complete α-blockade, and dosages of this agent should be titrated to blood pressure control.

Calcium-channel blockers do not provide α-blockade and therefore are not indicated. Labetalol has been reported to effectively control hypertension in patients with pheochromocytoma. However, this agent is not a reliable α-blocker and the potential for intraoperative hypertension is greater with labetalol compared with phenoxybenzamine.

Because α-tone can exacerbate hypertension in this setting, β-blockade is not indicated for pheochromocytoma unless adequate α-blockade already has been administered. Before surgery, patients with pheochromocytoma should be euvolemic or slightly volume expanded. However, high sympathetic tone and pressure natriuresis associated with pheochromocytoma may cause volume depletion, which may result in secondary stimulation of the renin–angiotensin system and worsening hypertension. Diuretics are contraindicated because these agents may exacerbate this situation.
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