Double-blind, multi-centre trial to compare a once-daily combination of trimethoprim and sulfamethopyrazine with ampicillin 4-times daily in patients with urinary infections.

Sixty-eight patients with urinary infection were allocated at random to receive treatment with either 500 mg ampicillin 4-times daily or a trimethoprim (250 mg)/sulfamethopyrazine (200 mg) combination given once daily after a double, loading dose on the first day. All patients complained of urinary symptoms and showed significant bacteriuria, E. coli being the pathogen most frequently recovered. Clinical and microbiological assessments were carried out on entry and, as a rule, after 3 to 4 days and 1 to 2 weeks of treatment. In the 35 patients receiving trimethoprim/sulfamethopyrazine, 40 (95%) of the 42 original infecting organisms were eradicated. In the 33 patients on ampicillin, the eradication rate was 32 (89%) out of 36 organisms. The course of urinary symptoms was similarly favourable in the two groups. Overall response was considered as 'excellent' or 'good' in 89% of the patients receiving the combination preparation and in 82% of those given ampicillin. Clinical and biological tolerance was satisfactory under both regimens. A longer follow-up control should confirm the value of the new combination in the treatment of urinary infections.