Famotidine for dogs: Dosage chart and safety considerations

In this article:

• What is famotidine?
• What is famotidine used for in dogs?
• Is famotidine safe for dogs?
• Can dogs overdose on famotidine?
• Can you give your dog famotidine every day?
• How to give your dog famotidine
• Famotidine alternatives for dogs

In this article

• What is famotidine?
• What is famotidine used for in dogs?
• Is famotidine safe for dogs?
• Can dogs overdose on famotidine?
• Can you give your dog famotidine every day?
• How to give your dog famotidine
• Famotidine alternatives for dogs

Famotidine is a common over-the-counter (OTC) drug that reduces stomach acid. It’s one of the drugs most commonly prescribed to dogs suffering from stomach irritation. Veterinarians are confident in its safety, though omeprazole may be their first choice in many cases. If you need to administer famotidine to your dog, it’s important to be aware of dosage guidelines and be aware of potential side effects and allergic reactions. 

What is famotidine?

Famotidine belongs to a class of drugs called histamine H2-receptor antagonists, or H2 blockers for short. H2 blockers are popular over-the-counter medications found in every drug store and supermarket under brand names like Tagamet (cimetidine), Pepcid (famotidine), and Zantac (ranitidine). They help people with heartburn, GI inflammation, ulcers, and gastroesophageal reflux disease (GERD). Although they’re a type of antihistamine, they only block a type of histamine receptor found in the stomach linked to stomach acid production. Reducing stomach acid relieves symptoms and allows tissues in the stomach, esophagus, or small intestine to heal. They work the same way in dogs as in humans.

What is famotidine used for in dogs?

Famotidine reduces stomach acid secretion in dogs with stomach acid problems, such as ulcers, inflammation, acid reflux, and vomiting. Veterinarians also prescribe it when they’re concerned a dog may develop ulcers or inflammation of the esophagus or stomach, such as when a dog is being treated with an NSAID, vomiting frequently, or having problems with acid reflux. 

The veterinary use of famotidine is off-label, meaning the Food and Drug Administration (FDA) has not approved it for use in dogs or other animals. This is a common practice in veterinary medicine.

Famotidine for ulcers

Dogs, like humans, can develop ulcers due to various factors such as stress, kidney disease, liver disease, extreme exercise, medication side effects, and inflammatory conditions. The incidence of ulcers in dogs is unknown, but it’s a common problem in veterinary practice. 

Pet owners cannot identify whether or not a dog has an ulcer specifically, but it will be obvious that there’s a problem. The most common signs of an ulcer in a pet are:

• Vomiting
• Loss of appetite
• Abdominal pain
• Weight loss

The dog may have black and tarry stools or have blood in the vomit, but not always. The signs of a severe ulcer are severe pain, weakness, and shock.

The only way to know if a dog has an ulcer is for a veterinarian to perform an endoscopic examination. Once an ulcer has been diagnosed, veterinarians usually prescribe proton pump inhibitors (PPIs) like omeprazole to reduce gastric acid. Famotidine isn’t as effective as omeprazole, but it is commonly used for stomach ulcers in dogs. 

Famotidine for inflammation

As with humans, dogs can suffer from irritation and inflammation of the esophagus or stomach due to stomach acid. Vomiting, acid reflux, infections, medicines, and autoimmune diseases can all cause either inflammation of the stomach lining (gastritis) or inflammation of the esophagus (esophagitis). Animals with these problems could develop stomach ulcers or erosion of the esophagus.

Veterinarians usually diagnose these problems based on the symptoms and an endoscopic exam. If the veterinarian suspects the cause of gastritis is an ulcer, omeprazole or famotidine are the best treatments. If the vet is worried about preventing an ulcer, famotidine may be the drug of choice. 

Famotidine is usually the drug of choice to reduce stomach acid in dogs with esophagitis. It’s effective, has minimal side effects, and only interacts with a few drugs. However, for severe esophagitis, a vet may prescribe omeprazole.

Famotidine for other conditions

When treating dogs for mast cell tumors or chronic kidney disease, a veterinarian may use famotidine or omeprazole to reduce side effects, help manage nausea, vomiting, and discomfort, or prevent ulcers.

Is famotidine safe for dogs?

Veterinarians consider famotidine a safe drug for dogs. Side effects and drug interactions are relatively minimal. However, no drug is 100% safe in all dogs. The veterinarian may be cautious or avoid giving the drug to some dogs.

Famotidine should never be given to a dog allergic to famotidine or any other H2 blocker (such as cimetidine).

Famotidine should be used cautiously in:

• Older dogs
• Dogs with heart disease 
• Dogs with kidney disease or liver disease

Although famotidine is safe for a pregnant or nursing dog, tell the veterinarian if the dog is pregnant or nursing.

Even though famotidine is easy to purchase at most retail stores and pharmacies, it is never safe to give your dog famotidine except under the direction of a veterinarian. 

Side effects of famotidine in dogs

When given as instructed by a veterinarian, famotidine has minimal side effects. The most common side effects are:

• Nausea
• Vomiting
• Loss of appetite
• Headache
• Dry mouth

Serious side effects are not documented in veterinary literature. A temporary decrease in heart rate has been noted when famotidine is administered quickly as an intravenous injection.

Interactions of famotidine with other pet meds

Compared to other stomach acid reducers, famotidine has relatively few drug interactions. This is one reason veterinarians may choose it to treat your pet. Even so, tell the veterinarian about all the drugs or remedies you give the dog just to be safe. This includes prescription drugs, OTC medicines, herbal remedies, vitamins, and supplements.

The biggest worry involves drugs that need to be digested by stomach acid to ensure proper absorption. These drugs won’t work as well if they’re taken with famotidine or any other stomach acid reducer. These drugs include:

• Certain types of antifungal drugs, such as ketoconazole and fluconazole
• The antibiotics cefpodoxime and cefuroxime
• The selective serotonin reuptake inhibitor (SSRI) fluoxetine 
• The immune-suppressing drug cyclosporine
• Iron salt supplements

Famotidine dosage for dogs

Famotidine doses for dogs are based on the dog’s weight. The standard dosage is 0.5 mg to 1 mg per kilogram of body weight daily. That works out to about 0.25–0.5 mg per pound. 

Famotidine for dogs dosage chart
Condition	Dosage
To reduce stomach acid concentrations	0.5–1.1 mg/kg given orally or by injection every 12 or 24 hours
For esophagitis	0.5–1.1 mg/kg given orally every 12 or 24 hours
As an add-on treatment for mast cell tumors	0.5 mg/kg every 24 hours

Can dogs overdose on famotidine?

Veterinarians have not specified a maximum dose but rarely prescribe more than the recommended daily dose of 0.5 mg to 1 mg. 

If a dog ingests too much famotidine, symptoms of the overdose might include vomiting, diarrhea, pale gums, and loss of appetite. Dogs tolerated even very high doses of famotidine in research studies with minimal side effects. A lethal overdose is possible but highly unlikely—the dog would have to swallow hundreds of store-bought famotidine tablets. However, do not take chances. Call a pet poison helpline or a veterinarian for advice if a dog has ingested too much famotidine.

Can you give your dog famotidine every day?

Pet parents will dose their dog daily for several weeks, but usually not much longer. In humans, healthcare providers usually prescribe famotidine only for short-term treatment—a few weeks to a couple of months—just enough to fix the problem. Veterinarians typically do the same. 

RELATED: Famotidine dosage, forms, and strengths

How to give your dog famotidine

Pet parents will give their dog famotidine by mouth as a tablet or a specially prepared oral suspension. Here are a few pointers:

• Follow all the veterinarian’s instructions for giving your dog famotidine.
• Give your dog famotidine for the entire duration prescribed, even if the dog’s symptoms improve.
• Famotidine should be given to the dog on an empty stomach. If a dog eats, that will stimulate gastric acid production before the famotidine can start working.
• Famotidine works best if given in the morning, about 30 minutes before the dog eats breakfast.
• If the dose causes nausea, vomiting, or other digestive system problems, try giving the dose with food.
• If you don’t know how to give a dog a tablet, ask a veterinary technician at the vet’s office to demonstrate. 
• Wash your hands before and after giving your dog a tablet.
• If it’s too difficult to give the dog a tablet, ask for a liquid formulation. A veterinarian or a compounding pharmacy can prepare it.
• If you give an oral suspension, shake the bottle before measuring a dose. Always measure the dose with an oral syringe. A veterinarian can provide one for free.
• Do not miss a dose. If a dose of famotidine is missed, give it when remembered. If the next dose is about two hours away, skip the missed dose. Give the next dose as scheduled. Never give the dog a double dose to compensate for a missed dose. 
• Do not stop giving the dog famotidine unless the veterinarian tells you to. Stopping the medicine can cause rebound hyperacidity, so the veterinarian may need to taper the dose. 
• Store this medicine at room temperature in a light-resistant container.

Famotidine alternatives for dogs

Famotidine is not always the first choice for stomach acid problems in dogs. For ulcers and more severe problems with acid reflux, veterinarians typically use proton pump inhibitors. The favored drug is omeprazole, better known by its brand name, Prilosec. 

Famotidine belongs to a class of drugs called H2 blockers. Only cimetidine and nizatidine are available in the U.S., but veterinarians are not eager to use them. Both are less potent than famotidine in dogs, and they have more drug interactions.

Antacids are another safe option, but only for mild conditions like heartburn. Veterinarians do not consider them effective at treating acid reflux or ulcers. Talk to the veterinarian first if you want to give your dog an antacid. Be sure to give the dog the antacid either two hours before or two hours after dosing it with famotidine. Some antacids can decrease the body’s ability to absorb famotidine.

Surgery is an option for severe ulcers or erosive esophagitis that doesn’t get better with medical treatment. 

For heartburn, you may want to try remedies that don’t involve drugs, such as changing the dog’s diet or giving the dog smaller but more frequent meals.

Bottom line: Famotidine is safe for dogs

Famotidine is a safe way to treat and prevent ulcers and other stomach acid problems in dogs. However, only give your dog famotidine when prescribed by a veterinarian. For maximum benefit, the best time to give your dog a dose of famotidine is half an hour before they’ve eaten in the morning.