Quick answer
Maropitant for cats is a prescription anti-vomiting medicine, best known by the brand name Cerenia. It blocks the signal in the brain that triggers vomiting and is approved in the US as an injection to treat vomiting in cats. Vets also use the tablets off-label. It controls the symptom, not the cause, so your vet still needs to find out why your cat is vomiting.
Maropitant for cats is one of the medicines vets reach for most often when a cat is vomiting. It works well, but it only controls the vomiting. This guide covers what it’s used for, how it’s given, how fast it works and the side effects to watch for.
What is maropitant used for in cats?
Maropitant is an antiemetic, a medicine that stops vomiting. It blocks a receptor in the brain, called NK-1, that’s part of the vomiting reflex. The best-known brand is Cerenia.
In the US, Cerenia for cats is FDA-approved as an injection to treat vomiting in cats aged 4 months and older. In the field study behind that approval, cats were vomiting from many causes, including gastroenteritis, pancreatitis, inflammatory bowel disease, cancer and fatty liver disease. In the first 24 hours, 1.8% of cats given maropitant vomited, compared with 18.5% of cats given a placebo.
Vets use it for:
| Use | What it does |
|---|---|
| Sudden vomiting | Stops vomiting while the cause is treated |
| Nausea | May ease the queasy feeling that can put a cat off food |
| Motion sickness | Prevents vomiting on car trips |
| Kidney disease | Reduces ongoing vomiting in some cats with chronic kidney disease |
| Before sedation | Reduces vomiting caused by some sedative and pain drugs |
As an anti-nausea medication, it can also help a cat feel well enough to eat. Vets care about this because a cat that feels sick for days can develop a lasting dislike of its food, lose weight or develop a serious liver problem called hepatic lipidosis. VCA notes that maropitant may also give mild pain relief. It works better on vomiting than on nausea itself, though: in a study of cats given sedative and pain drugs, it cut vomiting but not drooling or lip-licking, which can be signs of nausea.
Does maropitant help with motion sickness?
Yes. In a 2008 study, maropitant was highly effective at preventing motion sickness vomiting in cats. If your cat vomits in the car, ask your vet whether it’s a good option and exactly when to give it before you travel.
How is maropitant given to cats?
Maropitant comes in two main forms. Your vet will choose the form and set the dose for your cat.
- Injection. Given under the skin or into a vein at the clinic. This is the form approved for cats in the US, and it’s useful when a cat is vomiting too much to keep a tablet down
- Tablets. Given by mouth at home. Cerenia tablets are approved for dogs, and their use in cats is off-label, which is common and legal in veterinary medicine
VCA suggests giving the tablets with a small amount of food, which helps prevent vomiting, but not wrapping the pill too tightly in food, as that can stop it being absorbed properly. Wash your hands after handling the tablets, because skin contact can cause an allergic reaction in some people. Our guide on how to give a cat a pill has tips if your cat resists.
If you miss a dose, give it when you remember, then wait the usual time before the next one. Never give two doses at once.
How fast does maropitant work?
According to VCA, maropitant takes effect quickly, in about 1 to 2 hours. A single dose lasts about 24 hours. A study in cats found a terminal half-life of 13 to 17 hours and a 24-hour duration of action. VCA notes the effect can last longer in pets with liver or kidney disease.
If your cat is still vomiting several hours after a dose, call your vet. It can mean the cause needs different treatment.
What are the side effects of maropitant for cats?
Maropitant is generally well tolerated. In a safety study, cats handled doses at least 10 times higher than the effective range without adverse signs. Side effects can still happen.
| Effect | What it looks like | What to do |
|---|---|---|
| Injection pain | Crying out, hissing, pulling away or scratching during the injection | Normal and short-lived. Ask whether a chilled injection is possible |
| Tiredness | Sleeping more, dull | Monitor Watch at home. Call if it gets worse |
| Reduced appetite or drooling | Ignoring food, wet chin | See vet soon Call if your cat hasn’t eaten within a day |
| Swelling at the injection site | Lump or tenderness under the skin | Monitor Mention it to your vet |
| Trouble breathing, wobbliness, tremors or seizures | Rare reactions | Emergency Call your vet now |
The label for Cerenia lists these reactions in cats, in order of how often they’re reported: tiredness, reduced appetite, drooling, pain or crying out during injection, trouble breathing, wobbliness, fever, lying down and not getting up, vomiting, panting, seizures and muscle tremors.
Injection pain is the side effect owners notice most. The label says using refrigerated product may reduce the pain response to injection under the skin.
Why does my vet still need to find the cause of vomiting?
Maropitant treats the symptom, not the cause. The Cerenia label says the underlying cause of sudden vomiting should be identified and addressed in cats that receive it.
Cornell Feline Health Center lists many causes of vomiting in cats, from hairballs, spoiled food and parasites to swallowed string, toxic plants, human medicines and antifreeze. An anti-vomiting drug can make a cat look better for a while even though a serious problem is still there.
That’s why your vet may examine your cat’s belly, run bloodwork or take x-rays before or alongside maropitant. See our guide to cat vomiting for which signs mean a same-day visit.
Maropitant may also not fix everything on its own. In a study of cats with chronic kidney disease, it reduced vomiting, but it didn’t significantly improve appetite or weight. A cat that still isn’t eating needs a recheck. If appetite is the main problem, ask your vet about mirtazapine, an appetite stimulant.
Which cats need extra caution with maropitant?
Tell your vet about every health problem and medicine before your cat takes maropitant. Extra care is needed in cats:
- With a possible blockage in the gut. The label says its safety hasn’t been tested in cats with a gastrointestinal obstruction, and VCA advises against using it in these cats
- That may have swallowed a toxin. It hasn’t been tested in poisoned cats either. Call your vet or a poison hotline instead of trying to stop the vomiting at home
- With liver disease. The liver breaks down maropitant, so the label advises caution
- With heart disease, according to VCA
- That are pregnant, nursing or used for breeding. Safety hasn’t been established
- Under 4 months old. The injection is approved for cats 4 months and older
- Taking other medicines. Maropitant binds strongly to proteins in the blood, and some drugs, including certain antifungals, antibiotics, phenobarbital and anti-inflammatory pain medicines (NSAIDs), may interact with it
Never give your cat a human anti-nausea or anti-vomiting medicine. For after-hours help, see our cat emergency guide, and for other medicines your vet may prescribe, including antibiotics, browse our cat medications guides.
Frequently asked questions
How long does maropitant last in cats?
One dose lasts about a day. A study in cats found a 24-hour duration of action, and VCA notes the effects can last longer in cats with liver or kidney disease.
Does maropitant make cats sleepy?
Tiredness is the most commonly reported side effect in cats, along with reduced appetite and drooling. Some of this may come from the illness that caused the vomiting. Tell your vet if your cat seems very dull.
Is maropitant the same as Cerenia?
Yes. Maropitant is the generic name of the drug, and Cerenia is the best-known brand. VCA also lists Emeprev as another brand name.
Can maropitant help a cat that gets carsick?
It can. In a study of cats, maropitant was highly effective at preventing vomiting caused by motion. Ask your vet whether it suits your cat and when to give it before a trip.
Sources
- FDA-approved label (DailyMed): Cerenia (maropitant citrate) injectable solution
- Hickman MA et al. Safety, pharmacokinetics and use of maropitant (Cerenia) for the prevention of emesis and motion sickness in cats. J Vet Pharmacol Ther, 2008
- VCA Animal Hospitals: Maropitant Citrate
- Cornell Feline Health Center: Vomiting
- Quimby JM et al. Chronic use of maropitant for the management of vomiting and inappetence in cats with chronic kidney disease. J Feline Med Surg, 2015
- Martin-Flores M et al. Maropitant administered orally prior to morphine and dexmedetomidine reduces the incidence of emesis in cats. J Feline Med Surg, 2017
- Trepanier L. Acute vomiting in cats: rational treatment selection. J Feline Med Surg, 2010
Written by the CatsMed Team from the sources above. Reviewed by Dr. Jarod Grantland, DVM. It isn’t a substitute for seeing a vet. See how we research.
The CatsMed Team researches and writes every guide and tool on the site. We work from the references vets use: the Cornell Feline Health Center, the American Association of Feline Practitioners (AAFP), International Cat Care (iCatCare), the Merck Veterinary Manual, ASPCA Animal Poison Control and peer-reviewed studies. Every page lists its sources, and we update pages when guidance changes.
Not every guide has been reviewed by a veterinarian: the ones that have say so at the bottom and name the reviewer. None of them replaces a vet. If your cat is unwell, call your vet.
Dr. Jarod Grantland, DVMVeterinary reviewerDr. Jarod Grantland earned his Doctor of Veterinary Medicine from the Auburn University College of Veterinary Medicine in 2009. Since 2014 he has run Athens Animal Hospital in Athens, Alabama, caring for companion animals and livestock.
He reviews selected CatsMed guides. A guide shows his name only after he has approved that exact version of the text, and it goes back to unreviewed if the text changes.
