A 39-year-old woman with a biochemically confirmed catecholamine-secreting tumour is scheduled for laparoscopic adrenalectomy. Preoperative preparation begins two weeks before surgery. Which drug regimen correctly precedes and permits safe use of the other class?
- A Phenoxybenzamine first for 7 to 14 days, then a beta-blocker added only after adequate alpha-blockade ✓
- B Propranolol first for two weeks, then phenoxybenzamine added one day before surgery
- C Metyrapone alone for two weeks with no adrenergic blockade
- D Labetalol monotherapy started on the morning of surgery
Correct answer: A. Phenoxybenzamine first for 7 to 14 days, then a beta-blocker added only after adequate alpha-blockade
Explanation
Irreversible alpha-blockade with phenoxybenzamine must precede any beta-blocker. Blocking beta-mediated vasodilation first leaves alpha-mediated vasoconstriction unopposed and can precipitate a hypertensive crisis. Beta-blockade is added afterwards solely to control reflex tachycardia. Metyrapone blocks cortisol synthesis and has no role in catecholamine excess.
Reference: Williams Textbook of Endocrinology, 14th ed.
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