GI13 - Effect of Transdermal Mirtazapine on Appetite Recovery in Hospitalized Cats with Hepatobiliary Disease

Abstract: Background – Anorexia is a well-known clinical sign in feline hepatobiliary disease. Mirtazapine is widely used as an appetite stimulant, but data regarding its efficacy and safety in acutely-ill feline patients with hepatobiliary disease remains limited. Hypothesis/Objectives – This study aims to explore the effect of transdermal mirtazapine in hospitalized cats with hepatobiliary disease. It was hypothesized that cats receiving mirtazapine treatment would resolve anorexia sooner, and this treatment would not induce relevant side effects. Animals – Twenty-nine client-owned cats hospitalized with hepatobiliary disease and showing signs of anorexia were included: 15 in the control group and 14 in the mirtazapine group. Methods – An ambispective study was performed, combining a prospective randomized trial with a retrospective cohort study. All cats received standard and individualized treatment for hepatobiliary disease, with cats in the mirtazapine group receiving concurrent treatment with mirtazapine transdermal ointment (2mg/cat q24h) (Mirataz®). Results – Cats receiving adjunctive mirtazapine treatment resumed voluntarily eating a median of 7.5 days earlier than controls (p = 0.007) and had shorter hospitalization periods (p = 0.018). Although the difference was not significant (p = 0.087), cats receiving mirtazapine also showed a trend toward weight gain during hospitalization, in opposition to controls, which tended to lose weight. No clinically relevant side effects were observed. Conclusions and Clinical Importance – When used in association with individualized symptomatic treatment, the use of transdermal mirtazapine seems to be a safe adjunctive therapy that may facilitate a faster recovery from anorexia in hospitalized cats with hepatobiliary disease.