A 35-year-old man presents with episodic hypertension (BP up to 220/120 mmHg), diaphoresis, and palpitations. 24-hour urine shows elevated normetanephrine 3200 µg/day (normal <600). CT scan reveals a 4.2 cm right adrenal mass. Before adrenalectomy, the FIRST pharmacological step is:
- A Alpha-blocker (phenoxybenzamine) ✓
- B Beta-blocker (propranolol)
- C Calcium channel blocker (amlodipine)
- D Combined alpha+beta blockade simultaneously
Correct answer: A. Alpha-blocker (phenoxybenzamine)
Explanation
Alpha-blockade must always precede beta-blockade in pheochromocytoma preparation. Starting beta-blockers first leaves alpha receptors unblocked, causing unopposed alpha-adrenergic vasoconstriction and potentially fatal hypertensive crisis. Phenoxybenzamine (irreversible non-selective alpha-blocker) is the preferred agent, given for 10–14 days preoperatively. Beta-blockers are added after adequate alpha blockade only if tachycardia persists.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.