Clinical Question

What is the optimal antibiotic regimen for treating lower urinary tract infection (UTI) in children?

Evidence-Based Answer

For the afebrile child with a UTI, a short course (three to seven days) of antibiotics is as effective at preventing the recurrence of symptomatic UTI as a long course (seven to 10 days). There is no clear evidence of superiority for any one antibiotic regimen. (Strength of Recommendation: B, based on inconsistent or limited-quality patient-oriented evidence.)

Practice Pointers

Approximately 7% of girls and 2% of boys will have had a symptomatic UTI by six years of age.¹ Potential complications of UTI in children include urosepsis, renal abscess, and renal scarring. Guidelines recommend varying durations of treatment, ranging from five to seven days² to seven to 14 days.³

A 2003 Cochrane review of studies comparing different treatment durations of the same antibiotic found that two- to four-day courses of antibiotics were as effective as seven- to 10-day courses for eradicating lower UTIs in children without any increased risk of recurrence.⁴ The authors of this Cochrane review further explored the relative harms and benefits of different antibiotic regimens for treating lower UTIs in children. After excluding the nine studies that were reviewed in 2003, the authors were left with 16 studies of children who had bacteriologically proven lower UTI and no systemic symptoms (e.g., fever, flank pain).

Short courses of gentamicin (one trial), trimethoprim (one trial), pivmecillinam (not available in the United States; one trial), and cephalexin (Keflex; one trial) were evaluated, and, in two other trials, short courses of ampicillin, sulfisoxazole (no longer available), trimethoprim/sulfamethoxazole, nitrofurantoin (Furadantin), or a cephalosporin were used based on organism sensitivities.

All three dosing comparisons that were evaluated (single dose vs. 10 days, single dose vs. three to seven days, and three to seven days vs. seven to 10 days) demonstrated no difference in the rate of recurrent symptomatic UTI following treatment or in the rate of reinfection with a different organism following treatment. Head-to-head comparisons among antibiotics in the included studies found no differences in the rates of recurrent symptomatic UTI for 10 days of trimethoprim vs. 10 days of trimethoprim/sulfamethoxazole, or in the rate of persistent symptoms for 10 days of cefadroxil vs. 10 days of ampicillin. The studies included in the review did not report on the risks of renal scarring, and adverse event reporting was too inconsistent among studies to allow for meta-analysis.

Evidence in all 16 studies was rated as low quality because of small sample sizes and methodologic weakness (including lack of reporting on randomization methods, allocation concealment and blinding, and large losses to follow-up in some studies). Thus, this review does not conclusively rule out the possible superiority of one antibiotic regimen over another. Nevertheless, there were no clear differences in patient-oriented outcomes between single-dose, short-course, and long-course treatment of lower UTI in afebrile children, meaning that short courses should probably be preferred in practice.