Short-course ciprofloxacin treatment of acute uncomplicated urinary tract infection in women. The minimum effective dose. The Urinary Tract Infection Study Group corrected

BACKGROUND: Three studies were undertaken to determine the minimum effective dosing regimen of ciprofloxacin for the treatment of acute, symptomatic, uncomplicated lower urinary tract infection. METHODS: All studies were multicenter, prospective, randomized, double-blind trials. A total of 970 evaluable patients with a diagnosis of urinary tract infection received oral ciprofloxacin (200 mg to 500 mg daily in one or two divided doses for 1, 3, 5, or 7 days) or norfloxacin (400 mg twice daily BID for 7 days). The primary measure of efficacy was bacteriologic eradication at the end of therapy. RESULTS: In study 1, bacteriologic eradication was reported in 95 (89%) and 101 (98%) of patients in the groups who received ciprofloxacin, 500-mg single dose and 250 mg BID for 7 days, respectively. Clinical success occurred in 101 patients (94%) who received a 500-mg single dose and in 103 patients (100%) who were administered 250 mg BID for 7 days. In study 2, eradication rates in the groups who received ciprofloxacin, 100 mg BID for 3 days, 250 mg BID for 3 days, and 250 mg BID for 7 days, were 98 (93%), 95 (90%), and 98 (93%), respectively. Clinical success was reported in 102 (97%), 105 (100%), and 104 (98%) of the patients, respectively. In study 3, the eradication rates in the groups who received ciprofloxacin in dosages of 500 mg once daily for 3 days and 500 mg once daily for 5 days and norfloxacin in a dosage of 400 mg BID for 7 days were 137 (92%), 134 (90%), and 133 (94%) of the women, respectively. Clinical success was the same (97%) in all three groups. Overall, short-course (either 3- or 5-day) therapy with ciprofloxacin was statistically equivalent to conventional (7-day) therapy with either ciprofloxacin or norfloxacin. Single-dose ciprofloxacin therapy was statistically less effective than conventional treatment. CONCLUSIONS: Ciprofloxacin at a dosage of 100 mg BID for 3 days was the minimum effective dose for the treatment of uncomplicated urinary tract infection in women.