Double-blind clinical trial of a nitrofurantoin/sulphadiazine combination at two dosage levels in acute symptomatic urinary infections.

A double-blind trial was carried out in 177 patients with acute symptomatic urinary tract infections to assess the efficacy and tolerability of nitrofurantoin plus sulphadiazine at two dosage levels. Patients were allocated, at random, to receive 7-days' treatment with either 50 mg nitrofurantoin plus 150 mg sulphadiazine 3-times daily or 100 mg nitrofurantoin plus 500 mg sulphadiazine 3-times daily, and were followed-up 10 to 14 days later. Only the 73 (41%) patients with significant bacteriuria on entry were included in the analysis of the efficacy results. There were no statistically significant differences between the two treatments either in bacteriological cure rates, which were approximately 90% in both groups, or in the complete or partial resolution of symptoms, recorded in over 90% of patients at the 2-week follow-up visit. The main side-effects recorded were anorexia, nausea, vomiting and/or headache, and were fewer in the group treated with the lower dosage.