Acceptability, compliance, and adverse reactions when isoniazid, rifampin, and pyrazinamide are given as a combined formulation or separately during three-times-weekly antituberculosis chemotherapy.

In Hong Kong, 627 adult Chinese patients with newly diagnosed pulmonary tuberculosis received, for the first 2 months of chemotherapy, streptomycin together with isoniazid, rifampin, and pyrazinamide allocated at random to be given either as a combined formulation or separately. Each tablet of the combined formulation, which was designed for intermittent use, contained 125 mg of isoniazid, 100 mg of rifampin, and 375 mg of pyrazinamide. Patients weighing 42 kg or less received 5 tablets per dose, 43 to 57 kg, 6 tablets per dose, and 58 kg or more, 7 tablets per dose. The dosage of each drug was very similar whether it was given combined or separately. During the 2 months, spontaneous complaints, the commonest of which were nausea and vomiting, were made by 38% of patients receiving the combined and 39% receiving the separate formulations; 1% compared with 5%, respectively, complained that the tablets or capsules were too many, too large, difficult to swallow or that they stuck in the throat (p less than 0.05), and 32% compared with 45% regularly brought their own drink (usually milk or fruit juice) to the clinic to help them swallow their medicament (p less than 0.01). Only 14% of patients in each group missed one or more doses through default. Reported adverse reactions were mainly trivial, 4% of patients receiving the combined and 7% receiving the separate formulations having the administration of one or more drugs terminated. Thus, the differences between the combined and separate formulations showed a small advantage to the combined formulation in terms of acceptability to patients.