Lorazepam reduces recurrence of urethral obstruction in male cats: a prospective, randomized, double-blinded, placebo-controlled study.

Abstract

OBJECTIVE: To determine the efficacy of lorazepam in reducing the rate of recurrence in first-time feline urethral obstruction (UO) and frequency of lower urinary tract (LUT) signs following hospitalization, as well as adverse effects of the medication. METHODS: This was a prospective, randomized, double-blinded, placebo-controlled study of 80 client-owned male cats presenting to a university teaching hospital with UO between 2021 and 2025. Cats with urolithiasis or urinary tract infection were excluded. Cats received lorazepam or placebo for 1 month after hospitalization for UO. RESULTS: 41 cats received lorazepam and 39 cats received placebo. Sixty-four cats completed the study. Five of 64 cats experienced recurrence of UO, all receiving placebo. No cats receiving lorazepam had UO recurrence (0%; 95% CI, 0.0% to 10.9%) compared to the placebo group (15.7%; 95% CI, 5.2% to 33.7%); this was statistically significant. There was a statistically significant reduction in LUT signs for 2 of 33 cats during days 8 to 15 (95% CI, 0.7% to 20.2%) and 1 of 31 cats during days 16 to 30 (95% CI, 0.1% to 16.7%) for the lorazepam group. Ataxia was the only statistically significant side effect of lorazepam, occurring in 4 of 31 cats (13%); other reported effects included sedation, increased appetite, and vocalization. CONCLUSIONS: Lorazepam administration was associated with a reduction in the recurrence of UO in this study population, as well as reduced LUT signs compared to cats receiving placebo. Lorazepam administration was found to be safe. CLINICAL RELEVANCE: Lorazepam may be used safely in the reduction of both recurrent UO and LUT signs following alleviation of UO in male cats.