Omeprazole (Prilosec) for Dogs: Uses, Dosage & Side Effects

This information is for educational purposes only. Never give your pet any medication without your veterinarian's guidance. Dosing, frequency, and safety depend on your pet's specific health profile.

Omeprazole is an acid-reducing medication in the proton pump inhibitor (PPI) family. It works by blocking the stomach's acid pumps, which lowers acid production more strongly and for longer than many older antacid medications. In dogs, your vet may recommend it when stomach acid is contributing to irritation, ulceration, reflux, or pain.

This medication is commonly sold for people as Prilosec and is also available in veterinary settings and compounded forms. In dogs, it is usually prescribed off-label, which means your vet is using a human medication in a way that is accepted in veterinary medicine but not specifically listed on the human label.

Omeprazole is not a cure for every vomiting or stomach problem. It helps with acid-related disease, but it does not treat the underlying cause by itself. If your dog has ongoing vomiting, black stools, weakness, belly pain, or poor appetite, your vet may need to look for ulcers, medication side effects, liver disease, kidney disease, foreign material, or other GI conditions before deciding whether omeprazole fits.

Your vet may use omeprazole for dogs with stomach ulcers, upper intestinal ulcers, gastritis, or suspected acid reflux and esophagitis. It is also sometimes used when a dog is at higher risk for GI ulceration, such as after severe illness or when other medications may irritate the stomach.

In some cases, omeprazole is part of a broader treatment plan rather than a stand-alone medication. For example, your vet may pair it with other drugs for Helicobacter-associated disease, ulcer care, or severe GI inflammation. Dogs with repeated vomiting, lip licking, swallowing, nausea, or discomfort after eating may be evaluated for whether acid suppression could help.

Because many stomach symptoms overlap, omeprazole should not be started as a guess-and-check medication without guidance. A dog with vomiting could have pancreatitis, an intestinal blockage, toxin exposure, Addison's disease, kidney disease, or another problem that needs different care. Your vet can help decide whether acid reduction is appropriate, how long treatment should continue, and whether follow-up testing is needed.

Typical veterinary references list omeprazole for dogs at 0.5-1 mg/kg by mouth every 24 hours. Some dogs may be prescribed a different schedule based on the condition being treated, the formulation used, and your vet's goals. Because tablets and capsules come in fixed strengths, your vet may round the dose, use a compounded liquid, or choose a delayed-release product that best fits your dog's size.

Omeprazole is generally given on an empty stomach, often before the first meal of the day, because that can improve how well it works. Delayed-release tablets or capsules usually should not be crushed or split unless your vet or pharmacist specifically says that is safe. Crushing the wrong product can change how the medication is absorbed.

Do not change the dose or stop long-term use without checking with your vet first. If you miss a dose, give it when you remember unless it is close to the next scheduled dose. Then skip the missed dose and return to the regular schedule. Never give two doses at once.

If your dog has liver disease, kidney disease, is pregnant or nursing, or takes several other medications, dosing decisions may need extra caution. Your vet may also recommend a limited treatment trial, recheck exam, or additional diagnostics if symptoms are not improving within a few days.

Many dogs tolerate omeprazole well, especially for short courses. When side effects happen, they are often mild GI signs such as vomiting, diarrhea, decreased appetite, or gas. Some dogs may also seem a little less interested in food for a day or two when starting a new medication.

More serious problems are less common, but you should contact your vet promptly if your dog develops persistent vomiting, worsening lethargy, black or tarry stool, blood in vomit, severe diarrhea, weakness, collapse, or signs that the original stomach problem is getting worse instead of better. Those signs may point to the underlying disease rather than the medication alone.

With longer-term acid suppression, your vet may want to reassess whether the medication is still needed. Extended use can change stomach acidity and may affect how some nutrients or medications are absorbed. That does not mean long-term use is always wrong. It means the plan should be intentional and monitored.

If your dog accidentally gets into a large amount of omeprazole, overdose is often not severe, but any unusual symptoms still deserve a call to your vet or a pet poison resource. Bring the package strength and the estimated amount swallowed if you can.

Omeprazole can interact with other medications because it changes stomach acidity and can affect how certain drugs are absorbed or processed. Veterinary references advise caution with benzodiazepines, some antibiotics, clopidogrel, cyclosporine, diuretics, levothyroxine, and phenobarbital. Your vet may still use these combinations, but they may adjust timing, monitor more closely, or choose a different acid-control plan.

It is especially important to tell your vet about NSAIDs, steroids, seizure medications, thyroid medication, heart medications, supplements, probiotics, and any over-the-counter human products. Even when a combination is common, the details matter. Dose timing, your dog's age, and liver or kidney function can all change the risk profile.

Do not assume that because omeprazole is sold over the counter for people, it is automatically safe to combine with your dog's other medications. Before starting it, give your vet a complete medication list, including flea and tick products, joint supplements, antacids, and anything compounded.