Near Fatal Poisoning by Isoniazid and Rifampicin.

Since six decades, Isoniazid and Rifampicin are used as first line drugs for treatment of tuberculosis. The minimum acute lethal or toxic dose of Rifampicin is not well established. However, non-fatal acute overdoses in adults have been reported with doses ranging from 9 to 12 gm and fatal acute overdoses with doses ranging from 14 to 60 gm.