Development of interstitial pneumonia in a patient with rheumatoid arthritis induced by isoniazid for tuberculosis chemoprophylaxis.

Here, we report a 56-year-old patient with rheumatoid arthritis (RA) who had been treated with methotrexate and sulfuasalazine, but the disease activity remained high. Therefore, we planned TNF-blocker treatment for this patient. A tuberculin skin test was positive, we started anti-tuberculosis (TB) chemoprophylaxis with isoniazid (INH). However, liver dysfunction was appeared after 2 weeks from the start of INH. Therefore, we discontinued INH transiently and tried the desensitization of INH. However, interstitial pneumonia was developed 2 weeks after the re-start of INH, we decided to stop the INH prophylaxis. Interstitial pneumonia was improved by corticosteroid treatments. This case report shows that INH-induced IP can be occurred during the course of anti-TB chemoprophylaxis in patients with RA.