Randomized comparative trial and cost analysis of 3-day antimicrobial regimens for treatment of acute cystitis in women.

Objective: To determine the efficacy, safety, and costs associated with four different 3-day regimens for the treatment of acute uncomplicated cystitis in women.
Design: A prospective randomized trial with a cost analysis.
Study Population: Women with acute cystitis attending a student health center.
Interventions: Treatment with 3-day oral regimens of trimethoprim-sulfamethoxazole, 160 mg/800 mg twice daily, macrocrystalline nitrofurantoin, 100 mg four times daily, cefadroxil, 500 mg twice daily, or amoxicillin, 500 mg three times daily.
Results: Six weeks after treatment, 32 (82%) of 39 women treated with trimethoprim-sulfamethoxazole were cured compared with 22 (61%) of 36 treated with nitrofurantoin (P = .04 vs trimethoprim-sulfamethoxazole), 21 (66%) of 32 treated with cefadroxil (P = .11 vs trimethoprim-sulfamethoxazole), and 28 (67%) of 42 treated with amoxicillin (P = .11 vs trimethoprim-sulfamethoxazole). Persistence of significant bacteriuria was less common with trimethoprim-sulfamethoxazole (3%) and cefadroxil (0%) compared with nitrofurantoin (16%; P = .05 vs trimethoprim-sulfamethoxazole) and amoxicillin (14%; P = .11 vs trimethoprim-sulfamethoxazole). Persistence of bacteriuria was associated with amoxicillin-resistant strains in the amoxicillin group but nitrofurantoin-susceptible strains in the nitrofurantoin group. Trimethoprim-sulfamethoxazole was more successful in eradicating Escherichia coli from rectal cultures soon after therapy and from urethral and vaginal cultures at all follow-up visits compared with the other treatment regimens. Adverse effects were reported by 16 (35%) of 46 patients receiving trimethoprim-sulfamethoxazole, 18 (43%) of 42 receiving nitrofurantoin, 12 (30%) of 40 receiving cefadroxil, and 13 (25%) of 52 receiving amoxicillin. The mean costs per patient were less with trimethoprim-sulfamethoxazole ($114) and amoxicillin ($131) compared with nitrofurantoin ($155) and cefadroxil ($155).
Conclusions: A 3-day regimen of trimethoprim-sulfamethoxazole is more effective and less expensive than 3-day regimens of nitrofurantoin, cefadroxil, or amoxicillin for treatment of uncomplicated cystitis in women. The increased efficacy of trimethoprim-sulfamethoxazole is likely related to its antimicrobial effects against E coli in the rectum, urethra, and vagina.