A case of thrombocytopenia caused by rifampicin and pyrazinamide.

A 32-year-old male patient was diagnosed as having pulmonary tuberculosis and put on category II antitubercular regime since he had a history of antituberculosis treatment 10 years ago. Within 3 weeks, patient presented with ulcers in mouth, and blood picture confirmed thrombocytopenia. Rifampicin-induced thrombocytopenia was suspected and antitubercular treatment stopped. Patient improved and was re-exposed to the drugs one by one. After re-exposure with pyrazinamide, the platelet count decreased drastically and oral mucosal ecchymoses reappeared, while with rifampicin, thrombocytopenia was accompanied with petechiae on legs and forearms. Isoniazid, ethambutol, and streptomycin were continued.