Singapore Study of Intermittent Rifampicin Plus Isoniazid for Pulmonary Tuberculosis

In Singapore, 481 adult patients with newly diagnosed pulmonary tuberculosis were allocated at random to four regimens of intermittent rifampicin plus isoniazid. All patients received an initial two weeks of daily chemotherapy with streptomycin plus isoniazid plus rifampicin in standard daily dosages, followed by isoniazid 15 mg/kg body weight plus rifampicin 900 mg, both drugs twice a week (HR2 regimen) or once a week (HR1 regimen), or by isoniazid 15 mg/kg plus rifampicin 600 mg, both drugs twice a week (LR2 regimen) or once a week (LR1 regimen). All patients in addition received a supplementary daily capsule containing at random either rifampicin 25 mg or a matched placebo, to see if the daily supplement would reduce the incidence of adverse reactions to rifampicin.