Motion sickness in dogs: what the maropitant clinical trial measures
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
Gradual habituation remains the foundation against motion sickness, but it does not always suffice on its own. Two randomized clinical trials have precisely quantified the effect of a molecule now widely prescribed in veterinary medicine. Our full safety guidance is gathered in the dog travel and safety section.
Contents · 4 sections
Two trials, two scales
Gary Conder, Heather Sedlacek, John Boucher and Robert Clemence published, in 2008 in the Journal of Veterinary Pharmacology and Therapeutics, two randomized placebo-controlled trials of maropitant, a selective neurokinin-1 receptor antagonist.
- Exploratory trial (17 dogs): 10 of 17 dogs vomited on placebo, versus 3 of 17 on maropitant.
- Multicentre trial (211 dogs across 26 veterinary clinics in 12 US states): 69 of 105 dogs vomited on placebo, versus 15 of 106 on maropitant (highly significant difference, p < 0.0001).
- Depending on how far ahead of departure the dose was given, vomiting was reduced by 86.1% (two hours before) or 76.5% (ten hours before), relative to placebo.
What this study does not show
The trials measure prevention of vomiting, not the complete disappearance of discomfort: drooling, lethargy or nausea can persist without visible vomiting. Maropitant is a prescription-only drug, with its own possible side effects (injection-site pain, drowsiness): these trials do not replace an individualised veterinary opinion, particularly for a very young puppy or a dog with liver disease.
What it changes before a trip
- Ask the vet before a difficult trip rather than giving up on car outings out of fear of motion sickness.
- Combine treatment with gradual habituation: non-drug measures are detailed in our guide to dog car sickness and motion sickness solutions.
- Follow the timing your vet prescribes: the trial shows slightly higher efficacy at two hours than at ten hours before departure.
Frequently asked questions
Is maropitant available over the counter?
No, it is a prescription veterinary medicine, to be used according to your vet's prescribed dose and schedule.
Can it be used on every car trip?
That is a question for your vet: the trials cover a single dose ahead of one trip, not prolonged daily use.
What if the dog still vomits despite treatment?
No treatment removes the risk entirely: report the failure to your vet, who can adjust the dose or look into other causes. Find all our guides on the dog hub.
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This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.