Year: 2025
Type: article
Abstract: ABSTRACT The purpose of this study was to evaluate the pharmacokinetics of oral (PO) ondansetron compared to intravenous (IV) ondansetron in eight healthy client‐owned dogs. Dogs were randomized to one of two protocols in a crossover design, receiving PO or IV ondansetron at a dose of 1 mg/kg on Day 0 and the opposite formulation at an equal dose on Day 7. Plasma was collected at baseline and 1, 2, 4, and 8 h post administration. Ondansetron concentrations were measured utilizing liquid chromatography/mass spectrometry. For IV administration, AUC 0–8h was 1181 ± 619 ng/mL*h, with all dogs having detectable plasma concentrations at all time points. For PO administration, mean C max was 22 ± 11.3 ng/mL and AUC 0–8h was 61.7 ± 45.4 ng/mL*h, with all dogs having undetectable concentrations at various time points. Oral mean bioavailability was estimated at 5.2% ± 2.1%. Oral bioavailability of ondansetron is very low in healthy dogs, raising concern for the efficacy of ondansetron when given orally at 1 mg/kg. Future studies evaluating pharmacodynamics of ondansetron in nauseous client‐owned dogs should be performed to investigate whether plasma drug concentrations are the optimal way to assess the efficacy of oral ondansetron.
DOI: 10.1111/jvp.70024
Authors: Amanda Garrick, Kristin Zersen, Daniel Gustafson, Jessica Quimby, Amanda Diaz, Sarah Shropshire
Institution: Colorado State University
Language: English
Subfield: Small Animals
Field: Veterinary
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $4,520
Funder: Colorado State University
OpenAlex ID: W4414081901