Journal Article

Cephalexin twice daily versus four times daily for the treatment of urinary tract infections diagnosed in the emergency department

Rath, Abigail, Hamby, Aaron, Morrisette, Taylor, Billups, Kelsey, Burgoon, Rachel

2025

Overview

Cephalexin is an oral cephalosporin approved for the treatment of urinary tract infections (UTIs). Data regarding the optimal dosing interval for cephalexin in UTIs, including uncomplicated UTIs (uUTI) and complicated UTIs (cUTI), remains limited. The primary objective of this study was to compare the rates of treatment failure between patients prescribed cephalexin twice daily versus four times daily for the management of uUTIs and cUTIs once discharged from the emergency department (ED). This retrospective, single-center cohort study conducted between July 31st, 2016 and July 31st, 2023, included patients who were ≥ 18 years of age, discharged from the ED with a diagnosis of UTI, prescribed cephalexin 500 mg twice or four time daily, and a urine culture positive for Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis susceptible to cefazolin. Treatment failure was defined as return to the ED or outpatient clinic with similar or worsening UTI symptoms or change in antibiotic therapy within 30 days of the initial ED visit. Sub-group analyses were performed for both uUTI and cUTIs. In total, 214 patients were included in this analysis (50.0 % in each group). Treatment failure rates between the twice daily and four times daily dosing groups were 18.7 % versus 15.0 % (P = 0.465). Treatment failure rates in those with uUTI were 14.9 % versus 8.1 % (P = 0.197) and those with cUTI were 27.3 % versus 30.3 % (P = 0.786). For patients with UTIs, there was no statistically significant difference in treatment failure rates between patients prescribed cephalexin twice daily versus four times daily. These findings suggest cephalexin dosed twice daily may be a reasonable option for the outpatient management of UTIs diagnosed in the ED, thus increasing adherence and decreasing cost without statistically compromising effectiveness.

• Publisher: Elsevier Inc,Elsevier Limited
• Subject: Adult / Aged / Anti-Bacterial Agents - administration & dosage / Antibiotics / Catheters / Cefazolin / Cephalexin / Cephalexin - administration & dosage / Cystitis / Dosage / Dosing optimization / Drug Administration Schedule / E coli / Emergency / Emergency medical care / Emergency Service, Hospital / Female / Humans / Illnesses / Intubation / Male / Medical diagnosis / Middle Aged / Outpatient care facilities / Pain / Patients / Retrospective Studies / Statistical analysis / Treatment Failure / Urinary tract / Urinary tract infections / Urinary Tract Infections - drug therapy / Urinary Tract Infections - microbiology / Urine / Urogenital system