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The side effects of Cerenia for dogs is something for dog owners to watch for so to take prompt action should any arise.

 Cerenia is fairly new drug that may be given as an injection or given by mouth to dogs who are suffering from nausea and vomiting.

 As with many other medications, Cerenia may cause side effects in some dogs, although many dogs may not develop them. 

The side effects of Cerenia in dogs may vary from being mild to serious, although serious side effects are usually quite rare. 

Following is some information about Cerenia and the several side effects of Cerenia in dogs.

The side effects of Cerenia for dogs may be several.

The side effects of Cerenia in dogs may be several.

A Word About Side Effects of Cerenia in Dogs 

Cerenia generic name maropitant, is often prescribed to dogs with a history of acute vomiting. In studies, Cerenia has proven to be so effective, that even dogs who were given powerful emetics (substances known to cause vomiting) such as syrup of ipecac or apomorphine, failed to vomit courtesy of this drug.

It's often forgotten though that the act vomiting, albeit distressing to endure or witness, plays the fundamental role of ridding the body from harmful substances such as toxins, viruses and bacteria. The body is often an amazing, yet underestimated entity when it comes to curing itself naturally.

It is therefore important to understand that, while Cerenia is very effective in inhibiting vomiting, it fails to address the underlying cause of the vomiting. One must ask why is the dog vomiting in the first place? Masking the symptoms leads to delayed diagnosis and treatment. Fortunately, most vets are quite thorough in ruling out underlying causes of vomiting in dogs that need to be addressed before thinking of administering a powerful drug as Cerenia.

However, let's imagine for a moment the level of damage that may occur if a dog who has ingested toxin is administered Cerenia and the dog fails to vomit. 

Soon, the toxin will be absorbed by the body which may lead to important complications and even death. 

Complications may occur as well in small dog vomiting because of an intestinal obstruction from ingesting sharp pieces of plastic. 

Giving Cerenia to a dog with a blockage may temporarily stop the vomiting, while the plastic may cause intestinal perforation and life threatening peritonitis.

When dog owners report side effects of Cerenia in dogs, it may be therefore difficult to prove whether the dog is truly suffering from side effects from this drug or from complications deriving from the underlying cause of the vomiting itself. Even in reports of death from Cerenia in dogs, it is difficult to prove the cause of death unless the dog owners elects to have an autopsy done.

" Maropitant and other antiemetics should not be used in patients suspected of toxin ingestion, as this may mask progression and allow more time for toxin absorption. In addition, the use of these antiemetics should be delayed until a clinical examination and abdominal radiographs have ruled out GI obstruction."~Clinician's Brief

Side Effects of Cerenia in Dogs 

Many dog owners are concerned about the possibility of side effects of Cerenia in dogs. These concerns are not unfounded, considering that the drug information leaflet lists several potential side effects some of which can be quite scary. 

The drug information leaflet though fails going into more specific details which may be insightful for concerned puppy and dog owners. Following is more in depth information about the side effects of Cerenia in dogs.


According to the drug informational leaflet, when Cerenia was given once at a minimum dose of 8mg/kg to dogs prone to motion sickness, 26 dogs out of 208 (that's 12.5 percent) developed hypersalivation. Hypersalivation simply means that the dog's salivary glands produce excess saliva.

Dogs given a placebo though were also reported to suffer from hypersalivation. A placebo is not a medication, it is just a harmless medication without any physiological or therapeutical effect. No dogs were reported being euthanized though.

According to the field study, 19 dogs out of 195 developed hypersalivation and that's 9.7 percent. This is interesting because this is quite a large number and quite close to the number of dogs hypersalivation when receiving the actual drug.

Another European study revealed similar results. When dogs were given Cerenia at a minimum dose of 8mg/kg to dogs prone to motion sickness for 2 days, 5 dogs out of 107 developed hypersalivation (almost 5 percent). Two dogs out of 106 given the placebo developed hypersalivation as well (almost 2 percent).

The fact that dogs on the placebo salivated as well makes one wonder whether the simple fact of being in a study caused dogs enough stress to cause drooling. Where were the dogs housed during the study? Where the dogs treated ethically? Where any steps take to reduce stress in dogs if housed in a laboratory?


If your dog appears to have developed decreased activity levels and tiredness ever since you have been giving him his Cerenia pills, you are not imagining things. Although Cerenia is claimed to be non-sedating (which makes it a better choice than Benadryl or Dramamine for car sickness) a few dogs may develop drowsiness as a side effect.

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When a European field study tested dogs for adverse reactions from using Cerenia, 8 out of 107 dogs 8 developed drowsiness, lethargy or apathy. This is about 8 percent of researched dogs. Among dogs tested with placebos instead, 1 out of 106 only 1 developed drowsiness which comprises just one percent of placebo researched dogs.

In the U.S. field study, sedation or depression was found in 2 dogs out of 208 which means that roughly one percent were affected. Three dogs given a placebo out of 195 also developed sedation and/or depression.


Some dog owners report that their dog's stools may turn a bit on the mushy side when they are given Cerenia. Of course, not all dogs will develop this.

Back to the U.S field study, out of 206 dogs given Cerenia to prevent acute vomiting, 8 developed diarrhea. This means that roughly 3.9 percent were affected by the runs. When looking at dogs given the placebo, six out of 69 developed diarrhea. This is about 8.7 percent.

On top of diarrhea, some dogs also developed blood in their stools. Back to the study, out of 206 dogs, 4 developed bloody stools which is about 1.9 percent. Placebo dogs though were also affected with 5 dogs developing bloody stools, ultimately comprising 7.2 percent of the 69 tested.

Lack of Appetite

Many dog owners may wish to see their dogs stop vomiting when on Cerenia, but it may be upsetting as well dealing with a dog who doesn't want to eat. Fortunately, not many dogs appear to have been affected though when looking at the study.

Anorexia, the medical term for a lack of appetite was observed in 3 out of 206 dogs studied. This means only 1.5 percent were affected. Dogs given a placebo though apparently were not free from being affected. The study shows that out of 69 dogs 2 developed a lack of appetite which is 2.9 of the total placebo-tested dogs.

Local Pain at Injection Site 

There are reports of dogs feeling a sensation of pain at the injection site when injected with Cerenia. This appears to happen when Cerenia is preserved with a preservative known as metacresol. This effect can be reduced by keeping the medication refrigerated. However, recently, a formulation containing benzyl alcohol has been reported to reduce the pain.

A study was conducted on the effectiveness of the version of the drug preserved with benzyl alcohol and it was found to cause significantly less pain. On top of that, maropitant preserved with benzyl alcohol, offers the advantage of not needing to be refrigerated. It provides local pain control even when used at room temperature.

Can Cerenia Really Cause Death in Dogs?

The drug information leaflet for Cerenia lists death as an adverse reaction in a US field study evaluating dogs administered Cerenia. The dogs in the study were given Cerenia tablets and/or an injection once daily for up to 5 days. The leaflet mentions 10 dogs dying out of 206 receiving Cerenia, which is 4.9 percent. This can be a scary statistic for concerned dog owners. The leaflet also lists 2 dogs being euthanized during the study but there is no exact information as to why.

As discussed above, one may speculate that there may be chances that these dogs might have succumbed to disease processes already present and that failed to be addressed. However, the information leaflet mentions that in the field study Cerenia was given for the prevention of acute vomiting without referencing whether dogs were entirely healthy beforehand.

On the other hand, the study also mentions 4 dogs dying during the study out of 69, which is 5.8 percent when given a placebo. This leads to us pondering whether dogs may just die during studies. Perhaps they are old, frail or overly stressed making them more vulnerable.

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As with most medications, Cerenia can cause side effects in dogs

Further Considerations About Cerenia Side Effects in Dogs

Other Cerenia side effects in dogs include inflammation of the ear (3 dogs out of 206, 1.5 percent), endotoxic shock (2 dogs out of 206, 1 percent), blood in urine (2 dogs out of 206, 1 percent) excoriation, presence of erosion or ulceration caused by scratching, biting or rubbing ( 2 dogs out of 206, 1 percent).

When dogs were dosed for motion sickness, vomiting not related to motion sickness occurred in 11 dogs out of 208 (5.3 percent), muscle tremors occurred in 2 out of 208 dogs (1 percent), retching occurred in 1 out of 208 dogs (0.5 percent) and flatulence (intestinal gas) in 1 out of 208 dogs (0.5 percent).

Whether your dog develops side effects from the Cerenia may vary based on several factors. For example, allergies to the drug is always a possibility. The drug should be used with caution in dogs with impaired liver function. Cerenia has not be evaluated whether it is safe to use in pregnant or nursing animals.

The risks for Cerenia side effects in dogs are increased when Cerenia is combined with other drugs such as phenobarbital (a medication to control seizures); chloramphenicol (an antibiotic); ketoconazole along with some other antifungal drugs, certain types of thyroid hormone supplements, behavioral medications and some cardiac drugs, and non-steroidal anti-inflammatory drugs. Make sure your vet knows whether your dog is on other medications while taking Cerenia.

Did you know? Using Cerenia every day eventually risks depleting a dog's reserves of dopamine in their central nervous system leading to tremors (think Parkinson’s disease). According to veterinarian Dr. Jennifer Coates, giving Cerenia on a schedule of five days on–two days off, or every other day, helps prevents this side effect.

What to Do If Your Dog Develops Cerenia Side Effects 

Cerenia side effects in dogs can be reported directly to the manufacturing company. You can contact Zoetis Inc at 1-888-963-8471. Upon receiving your complaint, the drug company will have to submit a report of adverse drug experience to the FDA.

Adverse reactions can also be filed directly with the FDA using their form. Information on how to report an adverse reaction can be found here: Reporting Animal Drugs. 


  • Deckers N, Ruigrok CA, Verhoeve HP, et al. Comparison of pain response after subcutaneous injection of two maropitant formulations to beagle dogs. Veterinary Record Open 2018;5:e000262. doi:10.1136/vetreco-2017-000262
  • Conder GA, Sedlacek HS, Boucher JF, Clemence RG. Efficacy and safety of maropitant, a selective neurokinin 1 receptor antagonist, in two randomized clinical trials for prevention of vomiting due to motion sickness. J Vet Pharmacol Ther. 2008;31(6):528-532.

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