A controlled trial of calcium B-PAS

In a double-blind clinical trial, patients admitted to hospital with previously untreated active pulmonary tuberculosis were allocated alternately to two treatment schedules: 400 mg. isoniazid daily and either 15 g. of sodium PAS or 15 g. of calcium B-PAS daily. Patients with organisms initially resistant to either drug were withdrawn from the trial. 66 patients in the PAS group (56 initially culture positive) and 66 patients in the B-PAS group (53 initially culture positive) completed six months' therapy. After three months' therapy 10 patients in the PAS group were culture positive and in 2 cases the organisms were no longer fully sensitive to isoniazid; one of these was also no longer fully sensitive to PAS. After three months 8 patients in the B-PAS group were culture positive and in 2 cases the organisms were no longer fully sensitive to isoniazid. After six months' therapy 3 patients in the PAS group were culture positive and in 2 cases the organisms were no longer fully sensitive to isoniazid. After six months' therapy 2 patients in the B-PAS group were culture positive; one case was resistant to isoniazid and the other to PAS. Judging by clinical, radiological and bacteriological progress, calcium B-PAS (15 g. daily) proved as effective a companion drug for isoniazid as sodium PAS in equal dosage.