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News|Articles|February 25, 2026 (Updated: February 25, 2026)

LC-MS/MS Pharmacokinetic Analysis of Ondansetron Bioavailability in Canine Plasma

Author(s)John Chasse

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify ondansetron concentrations in dogs following intravenous and subcutaneous administration. Analytical results revealed 84.6% bioavailability and peak plasma concentrations of 84.6 ng/mL. The high sensitivity of LC-MS/MS enabled precise non-compartmental modeling to establish therapeutic dosing intervals for clinical use.

A joint study conducted by The Ohio State University (Columbus, Ohio), Virginia Tech University (Blacksburg, Virginia), and Colorado State University (Fort Collins, Colorado) evaluated the pharmacokinetic profile of ondansetron following intravenous (IV) and subcutaneous (SC) administration in five healthy adult female beagles. Ondansetron concentrations were quantified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A paper based on this study was published in the Journal of Veterinary Pharmacology and Therapeutics.1

Medications administered during the perianesthetic period can increase the risk of nausea and vomiting and result in aspiration, discomfort, and, if severe, death.2-4 While maropitant is often used to reduce the chance of vomiting in dogs, the expense and limited anti-nausea efficacy at the recommended dosage of 1 to 2 mg/kg reduces its utility.5,6 Ondansetron, a serotonin (5HT3) receptor antagonist, offers a cost-effective alternative due to its combination of both anti-nausea and antiemetic properties.7

As orally administered ondansetron in dogs have yielded limited efficacy and poor bioavailability, alternative routes of administration have been examined. The pharmacokinetics of intravenously administered ondansetron in sick dogs was examined in a recent study, and it was found that found that IV administration of 0.5 mg/kg ondansetron every 8 h resulted in therapeutic plasma concentrations (estimated to range between 10 and 250 ng/mL) and a reduction in nausea scores in the majority (83%) of patients, which established ondansetron's use as an effective antinausea medication.8 However, to date, the researchers involved with this study state that are no published data on the pharmacokinetics and bioavailability of subcutaneously administered ondansetron in dogs, thus inspiring their work.1

For this study, dogs were administered ondansetron at 0.5 mg/kg IV and SC in a randomized crossover design. On day 0 ondansetron was administered either IV (OV group) or SC (OS group), and 7 days later administered via the opposite route. Plasma samples were collected, and heart and respiratory rates, and rectal temperature were recorded over an 8 h period. Non-compartmental analysis was performed using commercially available software. Median (min-max) peak plasma concentration following OS was 84.6 (56.0-326.1) ng/mL, which occurred at the first sampled time point of 0.25 (0.25-0.5) h. The terminal half-life was longer in the OS versus the OV group. Bioavailability of ondansetron in the OS group was 84.6 (51.2-132.6)%.1

“Ondansetron administered SC at 0.5 mg/kg to adult healthy dogs has a similar bioavailability and a longer duration of action compared to the IV route of administration,” wrote the authors of the study.1 They propose that future pharmacokinetic and pharmacodynamic clinical studies should be performed in dogs utilizing the SC route of administration of ondansetron.1

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References

  1. Landau, E. D.; Boege, K. R.; Messenger, K. et al. The Pharmacokinetics of Intravenous and Subcutaneous Ondansetron in Female Beagle Dogs. J Vet Pharmacol Ther. 2026.DOI: 10.1111/jvp.70058
  2. Ryan, A. C.; Murrell, J. C.; Gurney, M. A. Post-Operative Nausea and Vomiting (PONV) Observed in a Clinical Study Designed to Assess the Analgesic Effects of inItravenous and Subcutaneous Methadone in Dogs. Vet J. 2022, 287, 105876. DOI: 10.1016/j.tvjl.2022.105876
  3. Foth, S.; Meller, S.; Kenward, H. et al. The Use of Ondansetron for the Treatment of Nausea in Dogs with Vestibular Syndrome. BMC Vet Res. 2021, 17 (1), 222. DOI: 10.1186/s12917-021-02931-9
  4. Moyer, A. L.; McKee, T. S.; Bergman, P. J. et al. Low Incidence of Postoperative Nausea, Vomiting, Regurgitation, and Aspiration Pneumonia in Geriatric Dogs Receiving Maropitant, Famotidine, and Fentanyl as Part of an Anesthesia Protocol. J Am Vet Med Assoc. 2021, 260 (S1), S46-S51. DOI: 10.2460/javma.21.05.0237
  5. Burke, J. E.; Hess, R. S.; Silverstein, D. C. Effectiveness of Orally Administered Maropitant and Ondansetron in Preventing Preoperative Emesis and Nausea in Healthy dogs Premedicated with a Combination of Hydromorphone, Acepromazine, and Glycopyrrolate. J Am Vet Med Assoc. 2021, 260 (S1), S40-S45. DOI: 10.2460/javma.21.02.0082
  6. Kenward, H.; Elliott, J.; Lee, T. et al. Anti-Nausea Effects and Pharmacokinetics of Ondansetron, Maropitant and Metoclopramide in a Low-Dose Cisplatin Model of Nausea and Vomiting in the Dog: A Blinded Crossover Study. BMC Vet Res. 2017, 13 (1), 244. DOI: 10.1186/s12917-017-1156-7
  7. Quimby, J. M.; Lake, R. C.; Hansen, R. J. et al. Oral, Subcutaneous, and Intravenous Pharmacokinetics of Ondansetron in Healthy Cats. J Vet Pharmacol Ther. 2014, 37 (4), 348-353. DOI: 10.1111/jvp.12094
  8. Sotelo, C. K.; Shropshire, S. B.; Quimby, J. et al. Pharmacokinetics and Anti-Nausea Effects of Intravenous Ondansetron in Hospitalized Dogs Exhibiting Clinical Signs of Nausea. J Vet Pharmacol Ther. 2022, 45 (6), 508-515. DOI: 10.1111/jvp.13087

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