SHORT-COURSE CHEMOPROPHYLAXIS WITH RIFAMPICIN, ISONIAZID AND PYRAZINAMIDE FOR TUBERCULOSIS EVALUATED IN GOLD MINERS WITH CHRONIC SILICOSIS - A DOUBLE-BLIND PLACEBO-CONTROLLED TRIAL

Setting: A medical facility for approximately 90 000 gold miners emplo yed on 24 South African gold mines. Objective: To evaluate the effecti veness of rifampicin, isoniazid and pyrazinamide given for 3 months fo r the prevention of tuberculosis in men with silicosis. Design: A rand omised double-blind placebo controlled trial with active 4-year follow up of subjects by routine radiographic screening. Results: A total of 382 gold miners with silicosis were randomised to receive rifampicin 600 mg, isoniazid 400 mg and pyrazinamide 1.25 g daily as Rifater(R) o r a placebo. These men have been followed for 4 years since the end of the treatment period. Eleven men who received the combination tablet and 15 men who received the placebo tablet have developed tuberculosis (chi(2) dfl = 0.66, P = 0.4). Conclusion: This multi-drug short cours e chemoprophylaxis regimen has failed to prevent tuberculosis in miner s with silicosis. Even if a larger study had demonstrated a statistica lly significant effect of the regimen as compared with placebo, the ra te of tuberculosis in the men who received the three-drug regimen was unacceptably high.