Single-dose therapy for cystitis in women. A comparison of trimethoprim-sulfamethoxazole, amoxicillin, and cyclacillin.

We evaluated single-dose regimens of trimethoprim-sulfamethoxazole, amoxicillin, and cyclacillin as treatment for acute cystitis in 38 women. The trial was prematurely stopped because of frequent treatment failures. At two days after treatment, all 13 patients given trimethoprim-sulfamethoxazole were cured, while four (31%) of 13 given amoxicillin and four (33%) of 12 given cyclacillin had persistent bacteriuria. At two weeks, 11 (85%) of 13 patients given trimethoprim-sulfamethoxazole, six (50%) of 12 given amoxicillin, and three (30%) of ten given cyclacillin were cured. One patient with positive results of antibody-coated bacteria testing who was treated with cyclacillin had signs and symptoms of acute pyelonephritis three days after treatment, and two patients treated with amoxicillin and one treated with trimethoprim-sulfamethoxazole converted antibody-coated bacteria test results from negative to positive after therapy. We conclude that single-dose treatment of cystitis in unselected women with cyclacillin and amoxicillin may result in low cure rates and that progression to acute pyelonephritis may occur following ineffective single-dose therapy.