Four-month, four-drug preventive therapy for inactive pulmonary tuberculosis.

Standard preventive therapy for inactive pulmonary tuberculosis (TB) is 12 mo of isoniazid. Shorter multiple-drug preventive regimens have been proposed. From December 1993 through January 1996 we evaluated a 4-mo, four-drug regimen of preventive therapy for patients with inactive TB, mostly newly arriving immigrants from countries with high rates of TB and of isoniazid resistance. Fifty-three evaluable patients received a 4-mo regimen of isoniazid, rifampin, ethambutol, and pyrazinamide. We compared their completion rate, side effects, and cost of treatment with those of 108 age-matched patients who had received 12 mo of isoniazid at an earlier time. Sixty-eight percent of patients on the 4-mo regimen completed treatment; 69% of those on the 12-mo regimen completed treatment (p = 0.9393). Side effects were more frequent for the 4-mo regimen (30.2%) compared with 12 mo of isoniazid (11.1%) (p = 0. 0027). The cost of providing an uncomplicated, self-supervised regimen was estimated to be almost four times greater for the four-drug regimen compared with isoniazid. These results show that, in terms of compliance, a four-drug, 4-mo regimen had no advantage over standard preventive therapy for persons with inactive pulmonary TB. On the other hand, the shorter, more intensive regimen was associated with more frequent adverse effects and was more costly.