Adverse drug reactions and outcome of elderly patients on antituberculosis chemotherapy with and without rifampicin.

Antituberculosis (anti-TB) chemotherapy with concomitant administration of rifampicin and isoniazid may cause a higher incidence of hepatotoxicity than isoniazid alone. We carried out a prospective study of the adverse reactions to anti-TB drugs and the clinical outcome in elderly patients on anti-TB chemotherapy, to find out whether the omission of rifampicin from standard anti-TB regime would result in a reduction of adverse reactions and/or mortality during anti-TB treatment. Eighty elderly patients (age > 65 years) with TB were recruited into the study. They were randomised to receive anti-TB chemotherapy consisting of isoniazid, pyrazinamide and ethambutol with or without rifampicin for six months. Adverse reactions and mortality occurring during treatment were noted. A significantly higher number of patients on rifampicin had elevated liver enzymes compared with those not receiving rifampicin. All of these reactions responded favorably to adjustment of anti-TB drugs. There was no significant difference between the two groups in the incidence of symptomatic adverse reactions or mortality during treatment. However, five patients not given rifampicin had unsatisfactory resolution radiographically and required additional therapy. We conclude that the inclusion of rifampicin in the anti-TB regime offers a better therapeutic response but without significantly affecting the incidence of adverse reactions or mortality during treatment in elderly patients with TB.