A 35-year-old man on standard RHZE therapy for pulmonary TB presents with acute onset painful swelling of the first metatarsophalangeal joint. Serum uric acid is elevated. Which drug is most likely responsible?
- A Pyrazinamide ✓
- B Isoniazid
- C Rifampicin
- D Ethambutol
Correct answer: A. Pyrazinamide
Explanation
Pyrazinamide inhibits renal tubular excretion of uric acid by acting on the URAT1 transporter, causing hyperuricemia. This can precipitate acute gouty arthritis, classically affecting the first metatarsophalangeal joint. Rifampicin is also uricosuric but pyrazinamide is the principal cause of anti-TB therapy-associated gout. Ethambutol causes optic neuritis, not gout.
Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.