Rifampicin-isoniazid and delayed elimination of theophylline: a case report.

This paper reports a case of tuberculosis relapse and chronic obstructive lung disease treated with rifampicin and isoniazid. The subsequent introduction of slow-release theophylline therapy revealed a delay in the theophylline elimination kinetics resulting in a toxic plasma level. Interference with hepatic microsomal enzymes is considered to occur.