Omeprazole for Dogs - Dosage, Usage and Side Effects

María Besteiros
By María Besteiros, Expert veterinary assistant and canine/feline hairdresser.. Updated: June 20, 2022
Omeprazole for Dogs - Dosage, Usage and Side Effects

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One of the World Health Organization's ‘essential medicines’[1], omeprazole is an antacid drug commonly used in human medicine. Various diseases and conditions treated with omeprazole can manifest themselves in our dogs. Gastrointestinal issues are quite common in canines, especially as they are often known to eat indiscriminately. This leads us to ask, ‘can dogs take omeprazole?’ Although omeprazole can be given to dogs, this doesn't mean we should just take a pill out of our medicine cabinet and give it to them.

At AnimalWised we detail everything you need to know about omeprazole for dogs, paying specific attention to its dosage, usage and side effects. Before we do, we remind you that any drug given to your pet should be first authorized by a qualified veterinarian.


  1. Can dogs take omeprazole?
  2. How does omeprazole in dogs work?
  3. What is omeprazole for dogs used to treat?
  4. Omeprazole dose for dogs
  5. Side effects of omeprazole for dogs
  6. Ranitidine or omeprazole for dogs?

Can dogs take omeprazole?

As stated in the introduction, it is possible for dogs to take omeprazole to relieve certain conditions. The most common problem with this drug is when it is used without a veterinary prescription. As a common drug in a home first aid kit, it is not strange to think some dog guardians would want to give their own medicine to their dog. If the drug is the same chemical makeup for humans as it is for dogs, then it is easy to assume we can give it to them.

If we look at our dog's symptoms, we might have an idea of what is wrong with them. Unfortunately, the symptomatology of the dog might suggest one problem, but the underlying cause is different. Achieving a correct diagnosis is something best done by a qualified veterinarian. Giving omeprazole to our dog requires us to know both the correct reason and the correct dosage.

While omeprazole is unlikely to cause serious poisoning in small amounts, we may be doing one of two things. Firstly, we may be giving the dog a drug which relieves symptoms, but doesn't actually treat the underlying problem. If the dog suffers from something more serious than mild gastrointestinal problems (such as complications deriving from tumors), the drug will only delay diagnosis and potentially exacerbate the long-term problem.

Secondly, if omeprazole is used without prescription, we might be doing more harm than good. A drug is only effective if administered properly. Omeprazole, along with a selection of other proton pump inhibitors (drugs inhibiting stomach acid production), were tested in a study from 2018[2]. This study showed that our knowledge of the drug's effects on dogs is still somewhat limited. For example, there was shown to be “no benefit pf once-daily PO-administered omeprazole”. It also discussed the possibility of omeprazole affecting the dog's metabolism, especially if they are taking any concurrent drugs.

It is the duty and legal requirement of veterinarians to know how to administer drugs to your pets. For this reason, they will be able to provide an appropriate diagnosis, prescribe the drug and also give you any additional information which will be essential to the dog's recovery.

How does omeprazole in dogs work?

Omeprazole basically acts as an antacid to reduce the production of stomach acid. More specifically, they are proton pump inhibitors which prevent the formulation of hydrochloric acid. It is commonly sold under the brand names Losec and Prilosec.

An excess of stomach acid can lead to gastric ulcers in dogs. As the excess gastric acid can cause reflux, this also poses a threat to the throat area. As it can also enter the rest of the gastrointestinal tract, it can cause problems on the mucosa of the intestines. The digestive system of a dog is a delicate balance and too much gastric acid can upset said balance.

There is some research to suggest that administering omeprazole can lead to quantitative changes in gastrointestinal microbiota of healthy dogs[3]. The same research points to the need for further research to better understand the effects of the drug. We do know that is has shown great efficacy for certain conditions which we detail below.

Omeprazole for Dogs - Dosage, Usage and Side Effects - How does omeprazole in dogs work?

What is omeprazole for dogs used to treat?

Omeprazole for dogs is prescribed both as a treatment for certain canine illnesses, but can also be used as a preventive medicine in other cases. These are both reasons why it is common for veterinarians to prescribe omeprazole for dogs with gastritis. Gastritis is an inflammation of the stomach lining which can have varying degrees of acuteness. The symptoms vary accordingly, but can include intense vomiting, lethargy and considerable discomfort. Omeprazole is used to redress the pH balance of the subject by inhibiting acid production.

If a dog is suffering from diarrhea, it is possibly due to enteritis. Enteritis is the inflammation of the bowel which can lead to malabsorption of nutrients and prevents proper fecal formation. Acute infectious enteritis is a form of this condition characterized by concurrent vomiting, fever and apathy. Omeprazole is only one type of drug which might be prescribed for these illnesses, but it is usually the most common.

Perhaps the most common use of omeprazole is as a preventive measure. This is often when the dog is required to take another medication which may affect gastric acid production. Corticosteroids are a drug which often needs to be taken for a long period of time, sometimes even during the course of a lifetime. One adverse side effect of taking corticosteroids is the development of gastrointestinal ulcers which warrants the use of omeprazole. The PPI acts as a preventive, but it is important to note that this is not used with otherwise healthy dogs.

Additionally, dogs with liver disease, kidney problems, stress related indigestion or chronic gastritis will be prone to ulcers. Cutaneous mast cell tumors may also cause ulcers, leading to the prescription of omeprazole. Any type of esophageal reflux may result in the prescription of this PPI.

Omeprazole dose for dogs

The amount of omeprazole prescribed to a dog will depend on various factors. The most important one will be the nature of the illness it is being used to treat, particularly in terms of progression and acuteness. However, this is not the only consideration. The medical history of the dog is also important as they might have contraindications which might affect the dosage.

The size of the individual dog is also an important factor in terms of omeprazole dosage. In general, controlling the intragastric pH of a dog will require 0.7mg to 1.0 mg/kg/d (i.e. up to 1 milligram per each kilogram of a dog's weight). However, some studies suggest this may not be sufficient a dosage to be as effective as it could be[4]. Regardless, it is up to the veterinarian to prescribe the correct dosage and it is our imperative to monitor its effects.

Side effects of omeprazole for dogs

The most important aspect of omeprazole side effects for dogs is that there are few of them. It is generally a safe drug to take with few important interactions with other drugs. An evaluation from the American Journal of Animal and Veterinary Sciences shows that adverse side effects in humans include:

  • Nausea
  • Abdominal pain
  • Constipation
  • Flatulence
  • Diarrhea

However, these side effects occurred in only 1.5%-3% of human patients and most of these are not observed in animals[5]. The same study used a case study of a Beagle which has been given omeprazole for 7 years and had shown no adverse side effects.

However, if used in high enough doses, omeprazole can affect acid production to the point that some bacteria are able to thrive. This is what leads to the aforementioned overgrowth of microbiota. Our lack of complete understanding of gut flora means we are not quite sure of the true effects of the drug, but it is believed it can affect individual dogs differently.

Omeprazole for Dogs - Dosage, Usage and Side Effects - Side effects of omeprazole for dogs

Ranitidine or omeprazole for dogs?

Ranitidine is an antacid drug that acts in a similar way to omeprazole, interfering with the production of gastric acid in the stomach. However, in general, omeprazole seems to have a more potent effect. In any case, it will be the veterinarian who will evaluate the dog's specific condition and prescribe accordingly. Ranitidine has also been withdrawn or suspended from use in many markets due to a possible carcinogenic risk, so omeprazole for dogs may be the only one available.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Omeprazole for Dogs - Dosage, Usage and Side Effects, we recommend you visit our Medicine category.


1. World Health Organization. (2021). List of Essential Medicines. Retrieved from:

2. Mars, S. L., et al. (2018). ACVIM consensus statement: Support for rational administration of gastrointestinal protectants to dogs and cats. Journal of Internal Veterinary Medicine, 32(6), 1823-1840.

3. Garcia-Mazcorro, J. F., et al. (2012). Effect of the proton pump inhibitor omeprazole on the gastrointestinal bacterial microbiota of healthy dogs. FEMS Microbiology Ecology, 80(3), 624–636.

4. Tolbert, K., et al. (2011). Efficacy of Oral Famotidine and 2 Omeprazole Formulations for the Control of Intragastric pH in Dogs. J Vet Intern Med, 25, 47–54.

5. Yavuz, O., & Arslan, H. H. (2018). Proton Pump Inhibitors in Veterinary Medicine. American Journal of Animal and Veterinary Sciences, 12(3),132-138

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1 comment
Andrew McCabe
Hi - FYI, Footnote 1 doesn't link to the intended page as the WHO has changed their site. Great article though, thanks very much. Andy
Administrador AnimalWised
Hi Andy,

Thank you for pointing this out. The article has been amended accordingly.
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Omeprazole for Dogs - Dosage, Usage and Side Effects