Fatal poisoning by isoniazid and rifampicin.

Isoniazid and rifampicin are used for management of tuberculosis. Acute poisoning due to isoniazid overdose is associated with repetitive generalized tonic-clonic seizures and severe metabolic acidosis. In toxic doses, rifampicin is known to produce hepatic, renal, hematological disorders, and convulsions. Sometimes, it may produce red man syndrome. We report a case of fatal poisoning with isoniazid and rifampicin. The case was characterized by late presentation, lactic acidosis, and renal failure.