Mirtazapine as an appetite stimulant and anti-emetic in cats with chronic kidney disease: a masked placebo-controlled crossover clinical trial.

Cats with chronic kidney disease (CKD) often experience inappetence and vomiting and might benefit from the administration of mirtazapine, a medication with appetite stimulant and anti-nausea properties. The aim of this placebo-controlled, double-masked crossover clinical trial was to evaluate the effects of mirtazapine on bodyweight, appetite and vomiting in cats with CKD. Eleven cats with stable CKD were randomized to receive 1.88 mg mirtazapine or placebo orally every other day for 3 weeks. After a 4 day washout period, each cat crossed over to the alternate treatment for 3 weeks. Physical examinations and serum biochemistry profiles were performed before and after each treatment period and owners kept daily logs of appetite, activity, behavior, and vomiting episodes. Compared to placebo, mirtazapine administration resulted in a statistically significant increase in appetite (P=0.02) and activity (P=0.02) and a statistically significant decrease in vomiting (P=0.047), as determined by Wilcoxon matched pairs analysis. Cats treated with mirtazapine also gained significant bodyweight compared with placebo-treated cats (P=0.002) as determined by linear mixed model analysis. Median weight gain during mirtazapine administration was 0.18 kg (range 0-0.45 kg). Median weight loss during placebo administration was 0.07 kg (range 0-0.34 kg). Mirtazapine is an effective appetite stimulant and anti-emetic for cats with CKD and could be a useful adjunct to the nutritional management of these cases.