Applying children's enuresis treatment with amitriptyline for canine post-spaying urinary incontinence: A pilot estriol-controlled randomized clinical trial.

Urinary incontinence due to urethral sphincter mechanism incompetence (USMI) affects up to 20% of bitches that undergo spaying surgery. Amitriptyline is a tricyclic antidepressant whose urinary retention is a reported side effect. This study aimed to assess the efficacy and safety of amitriptyline when compared to estriol orally. Fifteen bitches with a clinical diagnosis of post-spaying UI were evaluated during 60 days in a non-blinded randomized clinical trial. All patients were enrolled after clinical evaluation consisting of anamnesis, physical examination, and complementary exams (complete blood count, biochemical parameters, urinalysis, and abdominal ultrasound). The amitriptyline (AMT) group consisted of 8 bitches, which received the initial dose of 1 mg/kg every 12 h, whereas the estriol (EST) group consisted of 7 bitches which were initially treated with 1 mg/animal every 24 h. Patients underwent clinical evaluation at 7 days, and then at 21 and 60 days of treatment to assess safety and efficacy, as well as adjustments of dose when necessary. A urinary incontinence scale was used to assess the level of incontinence and therapeutic response to treatment. During the period of the study, estriol was fully effective in 71% of cases and amitriptyline in 62%. Both drugs proved safe in the medical treatment of USMI, with adverse effects such as somnolence (AMT, n = 5/8) and male attraction (EST, n = 1/7). The results support the amitriptyline recommendation as a substitute for estriol in USMI treatment.