Safety and Efficacy of Methenamine Hippurate for the Prevention of Recurrent Urinary Tract Infections in Adult Renal Transplant Recipients: A Single Center, Retrospective Study.

Background Recurrent urinary tract infections (UTI) are an important cause of morbidity and mortality in renal transplant recipients (RTR). Methods In this retrospective study we gathered clinical data from patients prescribed methenamine hippurate to prevent recurrent UTI pre- and post-intervention. Thirty-eight RTR >= 18 years old at Northwestern Memorial Hospital from 2006-2017 were included in the final analysis. Results The median and range for follow-up days were 365 (299-365) pre- vs 314 (105-365) post-methenamine. Total UTI frequency (9.16 vs 5.01/1000 patient follow-up days), days of antibiotic therapy to treat UTI (215 vs 132/1000 patient follow-up days), and hospitalization due to UTI (2.64 vs 1.07/1000 patient follow-up days) decreased while patients took methenamine. Escherichia coli and Klebsiella pneumoniae were the most commonly identified cause of UTI both pre- and post-intervention. Drug resistant bacteria (ESBL-producing or VRE) affected 3 patients pre- and recurred in 1 of those patients plus 3 new patients post-methenamine. Methenamine had few adverse side effects for patients. One patient had nausea and 1 was intolerant. Conclusion We found that methenamine is well tolerated and is useful in reducing UTI, antibiotic prescriptions, and hospitalization in RTR with recurrent UTI. Larger prospective studies are needed to confirm these findings.