A 50 year-old female who is being treated with a multidrug regimen for tuberculous pneumonia presents to a clinic complaining of pain and swelling in both arms and legs for the last two weeks. Physical exam is remarkable for a maculopapular rash across her nose and cheeks, and swollen, tender elbows and knees. Which of the following medications is likely responsible for her symptoms?
1.Ethambutol
2.Isoniazid
3.Pyrazinamide
4.Rifampin
5.Streptomycin
Correct answer
Isoniazid
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correct answer: B
This patient likely has drug-induced systemic lupus erythematosus (SLE). Isoniazid (INH) (choice B) is one of four drugs that classically causes this condition, and it fits this patient’s current drug regimen. The other three are hydralazine, procainamide, and phenytoin. INH may additionally result in peripheral parasthesias, which is usually prevented by supplementing its use with vitamin B6.
Pyrazinamide (choice B), Rifampin (choice D) and Streptomycin (choice E) are anti-TB drugs that may cause elevated liver enzymes. Ethambutol (choice A) is another anti-TB drug that may cause optic neuritis.