A woman treated for chronic refractory migraine with a serotonergic antimigraine agent for two years now complains of low back pain, and imaging reveals retroperitoneal fibrosis with hydronephrosis. The offending drug is:

• A Methysergide ✓
• B Propranolol
• C Topiramate
• D Amitriptyline

Explanation

Methysergide, a semisynthetic ergot alkaloid acting mainly as a partial 5-HT2 antagonist, is limited by retroperitoneal, pulmonary and cardiac valvular fibrosis after prolonged continuous use, so treatment requires drug holidays. This fibrogenesis resembles the valvulopathy seen with other potent serotonergic agents. Propranolol, topiramate and amitriptyline are standard migraine prophylactics without any documented fibrotic liability, ruling out the other three options.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.