Randomized controlled trial of the efficacy of short-term amitriptyline administration for treatment of acute, nonobstructive, idiopathic lower urinary tract disease in cats.

Objective: To determine whether short-term amitriptyline administration would be efficacious in the treatment of acute, nonobstructive, idiopathic lower urinary tract disease in cats.

Design: Randomized controlled trial.

Animals: 31 untreated male and female cats with acute, nonobstructive, idiopathic lower urinary tract disease.

Procedures: Cats were treated with amitriptyline (5 mg/d; n = 16) or a placebo (15) for 7 days and monitored for pollakiuria, hematuria, and adverse events. Cats were reexamined 1 month after treatment, and owners were interviewed by telephone 6, 12, and 24 months after treatment.

Results: 2 amitriptyline-treated cats were excluded from analyses because of acquired urinary tract infection. Clinical signs resolved by day 8 in 8 amitriptyline-treated and 10 control cats. There were no apparent differences in likelihood or rate of recovery from pollakiuria or hematuria between groups. Overall, clinical signs recurred significantly faster and more frequently in amitriptyline-treated than control cats. However, after excluding recurrences within 21 days of treatment, risk of recurrence was similar in both groups. Increasing age was significantly associated with increased likelihood and rate of recovery from hematuria and with decreased risk of recurrence of signs.

Conclusions And Clinical Relevance: Results suggest that short-term amitriptyline treatment has no benefit in terms of resolution of pollakiuria and hematuria in cats with idiopathic lower urinary tract disease and may be associated with an increased risk of recurrence.