A 39-year-old man with a biochemically confirmed catecholamine-secreting tumour is prepared for laparoscopic adrenalectomy. His resting blood pressure is 150/95 mmHg. Which preoperative regimen is correct?
- A Phenoxybenzamine for 10 to 14 days, then add a beta blocker for reflex tachycardia ✓
- B Propranolol first, adding phenoxybenzamine once the pulse rate falls below 70/min
- C Metyrosine monotherapy, with surgery performed once catecholamines normalise
- D Nifedipine alone, since calcium channel blockade fully replaces alpha blockade
Correct answer: A. Phenoxybenzamine for 10 to 14 days, then add a beta blocker for reflex tachycardia
Explanation
Alpha blockade must precede beta blockade. Irreversible alpha antagonism with phenoxybenzamine for 10 to 14 days expands the contracted intravascular volume; giving a beta blocker first removes vasodilatory beta-2 tone and can precipitate hypertensive crisis. Beta blockade is added afterwards purely for reflex tachycardia. Metyrosine blocks catecholamine synthesis but is used as adjunctive rather than sole therapy, and calcium channel blockers may supplement but do not replace alpha blockade in standard preparation.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.