2017 ACVIM Forum Research Abstract Program

Transdermal application of 2% MZP to the inner pinna achieves measureable plasma concentrations in cats. Absorption of 2% MZP was faster and more consistent following oral administration as compared to topical application. Additionally, the mean extent of absorption following oral administration was about 2fold higher than following topical application of 2% MZP. The longer apparent terminal half-life observed following topical as compared to oral administration (26.8 vs. 10.1 hr) suggests the presence of flip-flop pharmacokinetics, where the rate of absorption is significantly slower than the rate of elimination. Mirtazapine has been shown to increase body weight in cats and is transdermally absorbed. The purpose of this study was to evaluate multiple dose pharmacokinetics (PK) of mirtazapine 2% transdermal ointment (2% MZP) in cats.