Hepatotoxicity caused by the combined action of isoniazid and rifampicin.

A 35 year old black Somalian woman with miliary tuberculosis developed hepatotoxicity after a few days of treatment with isoniazid, rifampicin, pyrazinamide, and ethambutol. After withdrawal of all drugs the liver profile returned to normal and remained so after challenge with isoniazid. Hepatotoxicity recurred when rifampicin was added, but it was well tolerated when reintroduced without isoniazid.