2016 ACVIM Forum Research Abstract Program

At 0.8 mg/kg dolasetron does not maintain serum concentrations for 24 hours and does not adequately control xylazineinduced vomiting when given SQ even at 1 mg/kg. Additional dose studies are needed to determine if a higher dose is more effective. subcutaneously but has previously been demonstrated to have poor oral bioavailability and a short elimination half-life requiring frequent dosing (every 6-8 hours). Because of the impracticality of dosing (>3 doses/day) at home, it is often resigned to in-hospital administration. Ondansetron is a candidate for a transdermal medication because it is small in size (294 Daltons) and is moderately lipophilic (log p~2.1). The purpose of this study was to assess the pharmacokinetics of transdermal ondansetron administration in healthy, purpose-bred cats. Five purpose-bred cats with unremarkable CBC, biochemistry and urinalysis were utilized. 2 mg transdermal ondansetron Lipoderm gel was applied once to the internal ear pinna (total volume of 0.1 mL). Blood samples were collected via jugular catheter over a 48 hour period following administration (0, 15 minutes, 30 minutes, 1, 2, 4, 8, 12, 24 and 48 hours) . Serum was separated and frozen prior to analysis. Ondansetron was measured via liquid chromatography coupled to tandem mass spectrometry.