Cefdinir vs cephalexin for the treatment of urinary tract infections: A retrospective evaluation

Cefdinir and cephalexin are cephalosporin antibiotics commonly used in the treatment of urinary tract infections (UTIs). Their efficacy depends on achieving sufficient time with concentrations exceeding the minimum inhibitory concentration (MIC). Despite being frequently prescribed for UTIs, cefdinir has markedly lower urine penetration compared to cephalexin. It is possible that differences in pharmacokinetics could result in dissimilar efficacy between these agents; however, comparative studies of cephalosporins in UTIs are lacking.

This was a retrospective comparative study of patients discharged from emergency departments within a community health system with a diagnosis of acute cystitis who were prescribed cefdinir or cephalexin. Treatment failure rates at 7 and 14 days were compared between the 2 agents using a χ2 or Fisher's exact test, as appropriate.

There were no differences in overall treatment failure between the cefdinir and cephalexin groups. Treatment failure at 7 days occurred in 11.6% (n = 14) of patients in the cefdinir group and 8.3% (n = 10) of patients in the cephalexin group (P = 0.389). Treatment failure at 14 days was higher for cefdinir at 20.7% (n = 25) than for cephalexin at 11.8% (n = 14), but this difference was not statistically significant (P = 0.053). There were no differences in the rate of treatment failure in subgroup analyses of uncomplicated or complicated UTIs.

The results of this study suggest that cefdinir and cephalexin have comparable efficacy for the treatment of lower UTIs. While there was a numerically higher rate of treatment failure with cefdinir, there were no significant differences in treatment failure between the agents.