Controlled comparison of oral twice-weekly and oral daily isoniazid plus PAS in newly diagnosed pulmonary tuberculosis.

A controlled clinical trial was undertaken in 247 patients with newly diagnosed pulmonary tuberculosis to assess the relative efficacies of a fully supervised twice-weekly oral regimen of isoniazid plus PAS (para-aminosalicylic acid) and a standard self-administered daily regimen of the same drugs following an initial intensive phase of two weeks of daily streptomycin, PAS, and isoniazid. Among patients who had isoniazid-sensitive cultures initially and who attended the clinic regularly the numbers with a favourable bacteriological response at the end of the year of chemotherapy were 79 (88%) out of 90 for the twice-weekly regimen and 72 (87%) out of 83 for the daily regimen; the numbers of patients with considerable radiographic improvement were 54 (60%) and 53 (64%) respectively. Complaints of vomiting or diarrhoea that did not require a reduction of the PAS dosage were made on one or two occasions by 23(21%) out of 109 twice-weekly and 25 (23%) out of 108 daily patients, and on at least three occasions by 4 (4%) and 12 (11%) respectively. Finally, all five patients who had chemotherapy changed on account of hypersensitivity to PAS had been receiving the daily regimen, as also had one patient who died of agranulocytosis.