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Call your vet before giving Cerenia, or go straight in, if your dog may have swallowed a toy, sock, bone or anything toxic, has a swollen or painful belly, is retching without bringing anything up, has blood in the vomit or stool, or is a puppy with vomiting and diarrhea. Cerenia stops vomiting; it does not fix the cause, and the label says it has not been tested in dogs with a blocked gut or that have eaten a toxin. Call the same day if vomiting continues on Cerenia, or if your dog becomes very lethargic, wobbly, has facial swelling or trouble breathing after a dose.
The short answer: Cerenia (maropitant citrate) is the FDA-approved anti-vomiting drug for dogs. It blocks substance P, the main vomiting signal in the brain. There are two very different tablet doses: 2 mg/kg once daily to prevent vomiting from illness, and 8 mg/kg, four times as much, for car sickness, given at least 2 hours before the trip and for no more than 2 days in a row. In the label car-ride trial, 55% of dogs on placebo vomited versus 7% on Cerenia. One dose lasts about 24 hours. Its limit: it is much better at stopping vomiting than nausea, so a dog on Cerenia can still drool and feel queasy.
By Marc Brannigan and Natalie Mondine, co-founders of HempMy Pet · Published November 7, 2026 · Last reviewed November 7, 2026. We have grown and bottled full-spectrum hemp for pets on our own Colorado farm since 2016. We are not veterinarians — everything below comes from the published veterinary studies, consensus guidelines and drug labels listed at the end.
What Cerenia Is and What It Is Used For
Cerenia is made by Zoetis. The active ingredient, maropitant, is a neurokinin-1 (NK1) receptor blocker. Vomiting is triggered by a centre in the brainstem, and substance P is the key messenger there; by blocking it, Cerenia works against vomiting from both "central" causes, such as motion and some drugs, and "peripheral" causes in the gut. It needs a prescription.
- Tablets (peach-coloured, scored, 16, 24, 60 and 160 mg): to prevent acute vomiting in dogs 2 months and older, and to prevent vomiting from motion sickness in dogs 4 months and older.
- Injection (10 mg/mL): to prevent and treat acute vomiting in dogs, including vomiting caused by chemotherapy or other drugs, and to treat vomiting in cats. Vets give it under the skin or into a vein.
Common real-world uses: stomach bugs and dietary indiscretion, vomiting with pancreatitis, kidney disease or chemotherapy, before surgery to prevent vomiting from opioid premedication, and car trips. It does not treat diarrhea, and it is not a sedative or an anxiety medication.
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Cerenia Dose for Dogs: Two Uses, Two Doses
| Dog weight | Vomiting from illness (2 mg/kg, once daily) | Car sickness (8 mg/kg, once daily, max 2 days) |
|---|---|---|
| 10 lb (4.5 kg) | about 9 mg | about 36 mg |
| 25 lb (11.3 kg) | about 23 mg | about 91 mg |
| 50 lb (22.7 kg) | about 45 mg | about 181 mg |
| 75 lb (34.0 kg) | about 68 mg | about 272 mg |
| 100 lb (45.4 kg) | about 91 mg | about 363 mg |
Calculated from the CERENIA Tablets label minimum doses. Your vet picks the nearest whole or half tablet from the label charts (16, 24, 60 or 160 mg). For illustration only.
- Vomiting from illness: at least 2 mg/kg once a day. Puppies 2 to 7 months: up to 5 days. Older dogs: until the vomiting resolves; if it continues, your vet should re-examine your dog. A dog that is actively vomiting usually gets the injection first, because a tablet may come back up.
- Car sickness: at least 8 mg/kg once a day for up to 2 days, at least 2 hours before travel, with a small snack but not a full meal. The label says the injection should not be swapped in for the car-sickness dose.
- Should Cerenia be given with food? Food does not change how much is absorbed, but a small amount of food helps prevent the tablet itself causing vomiting on an empty stomach. Some dogs vomit the tablet if it is given with no food at all.
- Puppies: not under 8 weeks for the injection or 2 months for the tablets; see the bone marrow note under side effects.
How Fast Does Cerenia Work, and How Long Does It Last?
Tablets reach peak blood levels in about 1.5 to 2 hours; an injection under the skin peaks in about 35 minutes. That is why the label says to give tablets at least 2 hours before a car trip, and why vets inject it 30 to 60 minutes before an opioid premedication. In one surgery study, giving the injection 30 minutes ahead prevented vomiting from hydromorphone, but reducing nausea signs took 60 minutes (Hay Kraus 2014).
How many hours does Cerenia last? It is dosed once every 24 hours, and the anti-vomiting effect covers that day. In the car-sickness trials it still cut vomiting by 77% when given 10 hours before the ride, so an evening dose can cover an early-morning trip. Its half-life is roughly 4 to 8 hours at the 2 mg/kg dose and longer at 8 mg/kg, and with daily dosing it builds up: blood levels are about 2.5 times higher by steady state at 2 mg/kg and nearly 5 times higher at 8 mg/kg. That is one reason the car-sickness dose is limited to 2 days.
Does Cerenia Work? What the Trials Show
- Car sickness (label trial): 122 dogs with a history of motion sickness on a one-hour car ride: 67 vomited on placebo, 8 on Cerenia. A separate European trial found 69 of 105 placebo dogs vomited versus 15 of 106 on Cerenia (Benchaoui 2007).
- Acute vomiting (label trial): in 199 dogs seen at vet hospitals for vomiting, 50% of placebo dogs vomited again during the study versus 21.4% on Cerenia.
- Before surgery: in 88 rescue dogs given an opioid premedication, 62% of untreated dogs vomited versus 10% given oral Cerenia 2 hours earlier, and fewer looked nauseated (Burke 2021).
- Parvo: in a small randomised trial of 22 puppies with parvovirus, Cerenia and ondansetron performed the same for hospital stay, vomiting days and return to eating (Sullivan 2018).
Cerenia Stops Vomiting Better Than It Stops Nausea
Vomiting and nausea are not the same thing. In a blinded crossover study in 8 beagles given a chemotherapy drug, Cerenia and ondansetron both stopped every vomit, but Cerenia reduced nausea behaviour (drooling, lip-licking, restlessness) by only 25%, against 90% for ondansetron (Kenward 2017). A neurology study described Cerenia as not appearing to control the nausea of vestibular disease, the "old dog" balance problem, where ondansetron worked within an hour (Henze 2022). With opioid premedication before surgery, the pattern reversed and Cerenia beat ondansetron on both counts (Burke 2021).
The practical point: if your dog has stopped vomiting on Cerenia but is still drooling, licking its lips, refusing food or swallowing hard, it may still feel sick. Tell your vet; adding or switching to ondansetron is a common next step. It also stopped vomiting but not acid reflux under anaesthesia (Johnson 2014).
Cerenia Side Effects in Dogs
| Side effect | How common in the label trials | What to do |
|---|---|---|
| Drooling (hypersalivation) | 12.5% vs 9.7% on placebo (US car-sickness trials) | Usually passes; mention it to your vet |
| Vomiting the tablet | 5.3% at the 8 mg/kg dose; 9% vs 4% in the European trial | Give with a small snack next time |
| Drowsiness, lethargy | 8% vs 1% on placebo at 8 mg/kg for 2 days (European trial) | Usually passes; call if severe |
| Diarrhea, poor appetite | Similar to or lower than placebo in sick dogs | Call your vet if it continues |
| Pain or crying at the injection | The most-reported injection event after approval | Ask whether a chilled vial can be used |
| Facial swelling, trouble breathing, collapse, seizures | Rare post-approval reports | Emergency: go to a vet now |
Source: CERENIA Tablets and Injectable Solution FDA labels. Post-approval reports for tablets, most frequent first: anorexia, lethargy, drooling, vomiting, diarrhea, trembling, wobbliness, allergic reactions, weight loss, convulsions, hyperactivity, panting; deaths have been reported.
Will Cerenia make my dog sleepy? Sometimes, mostly at the 8 mg/kg car-sickness dose: 8% of dogs were drowsy versus 1% on placebo. It is not a sedative, so it will not calm an anxious traveller. How long do side effects last? In the trials they were short-lived and stopped with the drug; at the 2 mg/kg dose most of the drug is cleared within a day or two of the last dose.
Why the injection stings: the label says refrigerated product may reduce injection pain. Pain and vocalisation on injection is the most-reported event for the injection after approval.
Puppies: in puppies younger than 11 weeks, lab studies found reduced bone marrow cells more often and more severely with Cerenia than with placebo, although those study puppies were also sick with coccidia and some with parvo. This was not seen in puppies 16 weeks and older.
When You Should Not Give Cerenia
- Possible blockage or poisoning: stopping the vomiting can hide a foreign body or delay treatment of a toxin. The label says safety has not been evaluated in dogs with gut obstruction or that have eaten toxins.
- Without a cause in mind: the label says the underlying cause of vomiting should be identified and addressed. Repeated vomiting needs a diagnosis, not just a longer Cerenia course.
- Liver disease: use with caution, because it is cleared by the liver.
- Breeding, pregnant or nursing dogs: not evaluated.
- With other highly protein-bound drugs (NSAIDs, heart, seizure and behaviour medications): the label says use with caution, as the combination has not been studied.
Can a Dog Take Cerenia Long Term?
The label covers short courses. In a 28-day field trial of 32 dogs, reported effects included lethargy, vomiting, poor appetite, cloudy corneas and enlarged lymph nodes. In a 93-day safety study, 20 mg/kg a day (ten times the vomiting dose) caused weight loss, lower albumin and ECG changes. Vets do use it longer off-label, for example in dogs with chronic kidney disease, but long-term use should come with rechecks and a diagnosis for why the vomiting continues.
Cerenia vs Other Options
| Option | Used for | How it compares with Cerenia |
|---|---|---|
| Ondansetron | Nausea and vomiting, chemotherapy | Better for nausea in some studies; usually given 2–3 times a day |
| Metoclopramide | Vomiting, slow stomach emptying | Weaker; no effect on vomiting or nausea in the cisplatin model |
| Meclizine or dimenhydrinate | Car sickness (off-label in dogs) | Antihistamines; more sedating, much less trial data |
| Trazodone, gabapentin | Travel anxiety | Calming, not anti-vomiting; often paired with Cerenia for anxious travellers |
Ask your vet before giving any human motion-sickness product; dosing differs and some combination products contain ingredients that are dangerous for dogs.
For a dog that both panics and vomits in the car, Cerenia covers the vomiting and something else covers the fear. See trazodone for dogs, gabapentin vs trazodone and our guide to calmer car travel.
Where Hemp Fits
We make hemp oil, so here is the honest version. Hemp is not an anti-vomiting drug and does not replace Cerenia. One point is worth knowing: Cerenia is cleared by two liver enzymes, CYP2D15 and CYP3A12, and a 2024 dog liver study found CBD inhibits CYP2D15 but not CYP3A12 (Court 2024). Whether that changes Cerenia levels in real dogs has not been tested, so tell your vet if your dog takes both. Where many owners use hemp is the anxiety side of travel, and for that we would start a few days before the trip, not on the day:
- Our 90-day study was in dogs with joint discomfort, not nausea or travel, so we make no claim that it helps vomiting.
- Full side-effect figures are in hemp side effects in dogs, and drug interactions are covered in our hemp and dog medications guide.
Full-spectrum extract in cold-pressed hemp seed oil, grown and bottled on our own Colorado farm. Not an anti-nausea drug and not a replacement for Cerenia; many owners use it as part of a calmer travel routine. Tell your vet if your dog takes other medications. Third-party tested every batch. $99
Shop 1,000mg Hemp Seed Oil → See the StudyQuestions to Ask Your Vet
- Is this the 2 mg/kg illness dose or the 8 mg/kg car-sickness dose?
- How many days, and what do we do if the vomiting continues?
- Could this be a blockage or something my dog ate?
- If my dog stops vomiting but still drools or will not eat, should we add something for nausea?
- For car trips: does my dog also need something for anxiety?
More on the common causes: dog vomiting white foam, upset stomach home care and when a dog won't eat.
Frequently Asked Questions
What are the side effects of Cerenia?
In the label trials the most common were drooling, vomiting the tablet, and drowsiness at the higher car-sickness dose, which affected 8% of dogs versus 1% on placebo. The injection often stings. Rare post-approval reports include allergic reactions with facial swelling, wobbliness, seizures and collapse; those need a vet straight away.
Should Cerenia be given with food?
Give it with a small amount of food. Food does not change how much is absorbed, but a little food helps stop the tablet itself causing vomiting. Before a car trip, give it at least 2 hours ahead with a small snack, not a full meal.
How many hours does Cerenia last in dogs?
About 24 hours, which is why it is given once a day. In car-sickness trials it still reduced vomiting by 77% when given 10 hours before the ride. With daily dosing the drug builds up in the body, so courses are kept short.
Will Cerenia make my dog sleepy?
It can, mainly at the 8 mg/kg car-sickness dose: in a European trial 8% of dogs were drowsy versus 1% on placebo. At the lower dose for illness, drowsiness was uncommon. Cerenia is not a sedative and does not calm travel anxiety.
How long does it take for Cerenia to work in dogs?
Tablets peak in the blood in about 1.5 to 2 hours, so the label says to give them at least 2 hours before a car trip. An injection under the skin works faster, peaking in about 35 minutes; vets often give it 30 to 60 minutes before an opioid premedication.
What is the Cerenia dose for dogs?
For vomiting from illness, at least 2 mg/kg once daily. For car sickness, at least 8 mg/kg once daily for up to 2 days, given 2 or more hours before travel. Your vet chooses the nearest whole or half tablet of the 16, 24, 60 or 160 mg strengths.
When should I not give my dog Cerenia?
Do not give it without a vet check if your dog may have swallowed an object or a toxin, has a painful belly, is retching unproductively, or has blood in vomit or stool. Cerenia can hide the vomiting from a blockage. Use caution in liver disease and very young puppies.
How does Cerenia make a dog feel?
Most dogs simply stop vomiting. Cerenia is better at stopping vomiting than nausea, so some dogs still drool, lick their lips or refuse food. Some feel drowsy at the car-sickness dose. If your dog still seems nauseous, tell your vet, who may add ondansetron.
How long does it take for Cerenia to wear off?
At the usual 2 mg/kg dose the half-life is roughly 4 to 8 hours, so most of the drug is cleared within a day or two of the last dose. At the 8 mg/kg dose and after several days of dosing it lasts longer. Side effects in the trials were short-lived.
Can cats take Cerenia?
The Cerenia injection is FDA-approved to treat vomiting in cats at 1 mg/kg once daily for up to 5 days. The tablets are labelled for dogs only, although vets sometimes prescribe them for cats off-label. Never give a cat a dog-dose tablet without your vet.
The Short Version
Cerenia (maropitant) is the FDA-approved anti-vomiting drug for dogs. The illness dose is 2 mg/kg once daily; the car-sickness dose is 8 mg/kg, four times higher, given at least 2 hours before travel for no more than 2 days. It works well: 7% of car-sick dogs vomited on Cerenia versus 55% on placebo. It lasts about a day, is better at stopping vomiting than nausea, and should never be used to cover vomiting that might be a blockage or poisoning.
Full-spectrum hemp from our own Colorado farm: alongside your vet's plan, not instead of it
250mg Hemp Seed Oil Dogs under 25 lb $49 1,000mg Hemp Seed Oil Dogs 25 lb and up · the trial oil $99 
5,000mg Large Dog & Equine Oil Giant breeds · pump bottle $199
Grown on our own Colorado farm, third-party tested every batch, no xylitol, nothing artificial, 30-day returns. See the lab results · Serving by weight →
Hemp for Calm & Travel → Calmer Car Travel Guide
Dog Vomiting White Foam · Upset Stomach Home Care · Dog Won't Eat · Trazodone · Gabapentin vs Trazodone · Car Travel · Hemp & Dog Medications
Marc co-founded HempMy Pet in 2016 with his business partner Natalie Mondine, the company's COO. HempMy Pet breeds its own hemp genetics, grows them on its own Colorado farm, and formulates every batch in-house under human-grade standards — seed to sale, nothing sourced overseas. Every batch is third-party tested and the certificates of analysis are published. More about us.
HempMy Pet ran its own 90-day study of 37 dogs with chronic joint discomfort. Of the 32 that completed it, 30 (93%) showed a benefit, and 94% of owners reported their dog's quality of life had improved. It was overseen by Dr. Robin Downing, DVM, MS of the Downing Center for Animal Pain Management, with Lori Kogan, Ph.D. and Peter W. Hellyer, DVM of Colorado State University's College of Veterinary Medicine & Biomedical Sciences, and published in the Journal of the American Holistic Veterinary Medical Association. Read the methodology.
Why Dr. Downing: in 2005 she became only the third veterinarian in the world credentialed as a Diplomate of the American Academy of Pain Management. She founded the International Veterinary Academy of Pain Management, is a Diplomate of the ACVSMR, a Certified Veterinary Pain Practitioner and a Certified Canine Rehabilitation Practitioner, and was the AVMA's 2020 Bustad Companion Animal Veterinarian of the Year. Read the published paper (PDF).
This article is general information for dog owners, not veterinary advice. It is reviewed and updated as new peer-reviewed evidence is published, and where the evidence is thin or negative we say so.
How We Sourced This Article
Every claim above traces to one of these.
- US Food and Drug Administration / Zoetis. CERENIA Tablets label, NADA 141-262, rev. 1/2020 and CERENIA Injectable Solution label: doses, timing, pharmacokinetics, field trials, adverse reactions, puppy bone marrow findings, precautions, cat indication.
- Conder GA, Sedlacek HS, Boucher JF, Clemence RG. Efficacy and safety of maropitant in two randomized clinical trials for prevention of vomiting due to motion sickness in dogs. J Vet Pharmacol Ther. 2008;31:528–532. PubMed.
- Benchaoui HA, Siedek EM, De La Puente-Redondo VA, et al. Efficacy of maropitant for preventing vomiting associated with motion sickness in dogs. Vet Rec. 2007;161:444–447. PubMed.
- Kenward H, Elliott J, Lee T, Pelligand L. Anti-nausea effects and pharmacokinetics of ondansetron, maropitant and metoclopramide in a low-dose cisplatin model of nausea and vomiting in the dog. BMC Vet Res. 2017;13:244. PubMed.
- Burke JE, Hess RS, Silverstein DC. Effectiveness of orally administered maropitant and ondansetron in preventing preoperative emesis and nausea in healthy dogs. J Am Vet Med Assoc. 2021;260:S40–S45. PubMed.
- Hay Kraus BL. Effect of dosing interval on efficacy of maropitant for prevention of hydromorphone-induced vomiting and signs of nausea in dogs. J Am Vet Med Assoc. 2014;245:1015–1020. PubMed.
- Henze L, Foth S, Meller S, et al. Ondansetron in dogs with nausea associated with vestibular disease. J Vet Intern Med. 2022;36:1726–1732. PubMed.
- Sullivan LA, Lenberg JP, Boscan P, Hackett TB. Assessing the efficacy of maropitant versus ondansetron in the treatment of dogs with parvoviral enteritis. J Am Anim Hosp Assoc. 2018;54:338–343. PubMed.
- Johnson RA. Maropitant prevented vomiting but not gastroesophageal reflux in anesthetized dogs premedicated with acepromazine-hydromorphone. Vet Anaesth Analg. 2014;41:406–410. PubMed.
- Court MH, Mealey KL, Burke NS, et al. Cannabidiol and cannabidiolic acid: preliminary in vitro evaluation of metabolism and drug-drug interactions involving canine cytochrome P-450, UDP-glucuronosyltransferase, and P-glycoprotein. J Vet Pharmacol Ther. 2024;47:1–13. PubMed. Also VCA Hospitals, Maropitant citrate.
- Kogan L, Hellyer P, Downing R. The Use of Cannabidiol-Rich Hemp Oil Extract to Treat Canine Osteoarthritis-Related Pain: A Pilot Study. J Am Holist Vet Med Assoc. 2020;58:35–45. Our disclosure: HempMy Pet supplied the hemp extract and reimbursed clinic costs; we had no involvement in any other study cited here.
Spot something that conflicts with your veterinarian's advice? Email support@hempmypet.com and we will correct it.
These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease. This article is general information, not veterinary advice. Never start, stop or change your dog's medication without your veterinarian.
