Lorazepam study points to fewer repeat blockages in male cats
Bottom line
A new prospective, randomized, double-blinded, placebo-controlled JAVMA study suggests lorazepam may reduce repeat urethral obstruction in male cats after a first-time obstructive episode. The trial enrolled 80 client-owned male cats treated at the University of Minnesota between 2021 and 2025, excluding cats with urolithiasis, urinary tract infection, or neoplasia. According to the study report, cats that received lorazepam after discharge had a significantly lower rate of recurrent obstruction than cats given placebo, and they also had fewer lower urinary tract signs during follow-up. The study was published online May 6, 2026, and later corrected to clarify details including the number of cats that completed the study. (pubmed.ncbi.nlm.nih.gov)
Why it matters: Recurrent obstruction remains one of the most frustrating and costly complications after discharge, and this study adds controlled evidence for a discharge medication strategy in a space where prior options have been mixed. The rationale is clinically relevant: unlike prazosin, which targets smooth muscle and has shown inconsistent or unfavorable recurrence data in some studies, lorazepam may better match the anatomy of the distal male feline urethra because of its skeletal muscle relaxant and anxiolytic effects. In the accompanying AVMA Veterinary Vertex discussion, study author Dr. Kelly Tart said the protocol used 0.25 mg/cat orally every 12 hours for 30 days, started once cats were eating, with sedation and ataxia among the adverse effects to monitor. (veterinaryvertex.buzzsprout.com)
What to watch: Whether clinicians adopt lorazepam more broadly, and whether follow-up studies replicate the findings in larger, multi-center populations and help define which cats are the best candidates. (veterinaryvertex.buzzsprout.com)
Key facts
- Study type
- Prospective, randomized, double-blinded, placebo-controlled
- Population
- 80 client-owned male cats with first-time urethral obstruction
- Study site
- University of Minnesota
- Study period
- 2021 to 2025
- Intervention
- Lorazepam after discharge
- Comparator
- Placebo
- Main finding
- Lower recurrent urethral obstruction and fewer lower urinary tract signs with lorazepam
- Exclusions
- Urolithiasis, urinary tract infection, and neoplasia
- Publication date
- May 6, 2026
Lorazepam may be emerging as a new post-discharge option for male cats recovering from urethral obstruction. In a prospective, randomized, double-blinded, placebo-controlled study published online in JAVMA on May 6, 2026, investigators reported that lorazepam was associated with a significant reduction in recurrent urethral obstruction compared with placebo, along with fewer lower urinary tract signs after hospitalization. The work focused on first-time obstructed male cats, a group where recurrence risk is high and where discharge protocols often vary widely by clinician and practice. (pubmed.ncbi.nlm.nih.gov)
That matters because recurrence after relief of obstruction has long been a weak point in feline urinary care. Prior studies on prazosin, which has commonly been used in these cases, have not produced a clear benefit, and some data have suggested worse recurrence outcomes rather than better ones. The new lorazepam study enters that unsettled space with a stronger design than many earlier reports: prospective enrollment, placebo control, and double blinding. In the Veterinary Vertex podcast tied to the paper, the authors emphasized that recurrence often clusters in the first couple of weeks after discharge, making the immediate post-hospital period the key intervention window. (pubmed.ncbi.nlm.nih.gov)
According to the study abstract and article summary, 80 client-owned male cats presenting to a university teaching hospital from 2021 through 2025 were enrolled. Cats with urolithiasis, urinary tract infection, or neoplasia were excluded so the trial could focus on the most common plug-associated form of obstruction. The article summary identifies the site as the University of Minnesota. The abstract was later corrected in July 2026, and the article record also notes a May 27, 2026, correction involving placement of text about two cats removed because of potential adverse effects, underscoring the importance of reading the updated version. (pubmed.ncbi.nlm.nih.gov)
The mechanistic argument is part of what makes the findings stand out. In the AVMA podcast, Dr. Kelly Tart said many prior pharmacologic approaches have focused on smooth muscle pathways, while plugs often lodge distally in the penile urethra, where skeletal muscle predominates. Lorazepam, as a benzodiazepine, offers skeletal muscle relaxation along with anxiolysis, and the latter may also matter if stress-related behaviors contribute to recurrence or persistent lower urinary tract signs. In the same discussion, Tart said cats in the treatment arm received 0.25 mg/cat orally every 12 hours for 30 days, with treatment started in hospital once the cat was eating; she also described the drug as relatively inexpensive, citing an approximate 30-day cost of about $30 at the time. (veterinaryvertex.buzzsprout.com)
Industry and clinical reaction has been notably interested, in part because the headline result was striking. The Veterinary Vertex episode framed the finding as “zero re-obstructions” in the lorazepam group, while independent veterinary commentary on LinkedIn highlighted a reported 0% recurrence rate in the lorazepam arm versus 15.7% in the placebo arm, with statistical significance. That commentary is not a primary source, but it reflects the way some clinicians are already interpreting the paper: as one of the more actionable discharge studies to come out in feline urinary obstruction in recent years. (veterinaryvertex.buzzsprout.com)
Why it matters: For veterinary professionals, the bigger takeaway isn’t just that lorazepam “worked” in one study. It’s that the paper may shift the discharge conversation away from habit and toward mechanism-matched, evidence-based prescribing. If the benefit holds up, lorazepam could become a practical addition for selected first-time obstructed male cats, especially given the financial and emotional burden of repeat obstruction on clinics and pet parents. At the same time, this is still an 80-cat, single-center study, and clinicians will need to weigh sedation risk, paradoxical benzodiazepine reactions, and case selection carefully. Tart noted in the podcast that cats with prior concerning responses to benzodiazepines may not be ideal candidates. (pubmed.ncbi.nlm.nih.gov)
What to watch: The next step is external validation. Watch for larger or multicenter studies, protocol refinements around dose and duration, and any guideline-level discussion about whether lorazepam should displace prazosin in routine post-obstruction care. Just as important will be whether future work can tease apart which benefit matters most, skeletal muscle relaxation, anxiolysis, or both, and whether the approach also improves broader feline lower urinary tract disease outcomes beyond true re-obstruction. (veterinaryvertex.buzzsprout.com)