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Pepcid® is the brand name form of famotidine, an antihistamine that treats stomach ulcers and other chronic gastrointestinal conditions. Although formulated for human use, Pepcid® is commonly recommended by veterinarians to treat gastrointestinal symptoms associated with excess stomach acid. Read on to learn the dosage, efficacy, ingredients, and side effects of Pepcid® for dogs.


The dosage strength and frequency will vary depending on your dog’s symptoms, age, and weight. The standard recommended dosage is 10 mg for a 20 lb dog up to twice daily. However, before giving Pepcid® to your dog, always consult your veterinarian for advice and an official diagnosis. Pepcid® works best when given on an empty stomach.


Famotidine is one of the most effective stomach acid suppressants available. It interacts with fewer drugs than other H2 receptor antagonists and rarely causes side effects.

Pepcid® treats the following symptoms and conditions:

Pepcid® is a short-acting medication that lasts up to 24 hours. The duration may be longer in dogs with kidney or liver disease. Pepcid® may also be recommended for dogs taking medications or diagnosed with diseases that irritate the stomach or cause excess stomach acid secretion.

Ingredients in Pepcid®

The active ingredient in Pepcid® is famotidine, an antihistamine that inhibits stomach acid secretion.

Inactive ingredients include:

  • talc

  • hypromellose

  • red iron oxide

  • carnauba wax

  • titanium dioxide

  • magnesium stearate

  • pregelatinized starch

  • hydroxypropyl cellulose

  • microcrystalline cellulose

These ingredients add color, facilitate easy swallowing, help prevent caking, and increase the duration of a drug’s release into the system. If you have questions, ask your vet or pharmacist.

Side effects

Side effects associated with Pepcid® are rare, but usually mild. If you notice any of the following side effects, contact your vet immediately:

  • Vomiting

  • Diarrhea

  • Dry skin

  • Loss of appetite


The FDA has not approved Pepcid® for veterinary use. However, many veterinarians regularly recommend this over-the-counter medication for dogs experiencing chronic gastrointestinal symptoms. If you have any concerns about its safety, consult your veterinarian.

Use Pepcid® with caution in pregnant or lactating dogs, as well as those diagnosed with kidney or liver disease.

Additionally, the symptoms of stomach ulceration are similar to those of stomach cancer. To ensure the best prognosis in either case, it’s important to seek an official diagnosis before administering any medications, including Pepcid®.

Drug interactions

Pepcid® interacts with fewer drugs than other H2 antihistamines like cimetidine and ranitidine. Pepcid® may interfere with the body’s ability to absorb the following medications:

  • Iron salts

  • SSRIs (fluoxetine)

  • Heart medications (digoxin)

  • Immunosuppressants (cyclosporine)

  • Antibiotics (cefuroxime, cefpodoxime)

  • Other acid reflux medications (cisapride)

  • Antifungal medications (fluconazole, ketoconazole, and other -azole antifungals)

If your dog is taking any of these medications, administer them at least one hour prior to giving Pepcid®. Be sure to let your vet know if your dog is taking any supplements, over-the-counter medications, or prescription drugs.

Allergic reactions and sensitivity

Allergic reactions and sensitivity to famotidine are rare. If you notice signs of an allergic reaction, contact your vet immediately. Symptoms of an allergic reaction to famotidine include:

  • Rash

  • Fever

  • Facial swelling

  • Difficulty breathing

Frequently asked questions

Which form of Pepcid® should I give to my dog?

If you’re shopping around for Pepcid®, you’ll notice there are different types. Pepcid® Original Strength in the 10 mg dosage is safe for dogs. Avoid purchasing Pepcid® Complete or Pepcid® Maximum Strength, which contain additional ingredients and stronger dosages that could upset your dog’s stomach.

Is it possible for dogs to overdose on Pepcid®?

Overdose is rare. Keep all medications out of your dog’s reach. If you notice any of the following symptoms, contact your veterinarian or the Pet Poison Helpline immediately:

  • Collapse

  • Lethargy

  • Vomiting

  • Diarrhea

  • Pale gums

  • Restlessness

  • Difficulty breathing

  • Low blood pressure

  • Loss of coordination

  • Irregular or rapid heartbeat

If famotidine is an antihistamine, does it treat other types of allergic reactions?

Famotidine works differently than other antihistamines used to treat skin and nasal allergies. Famotidine is an H2 blocker. Skin and nasal allergies arise when histamine binds to H1 receptors. If your dog has skin or nasal allergies, ask your vet for advice on which medication to use.

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Written by Mel Lee-Smith

Veterinary reviewed by:

Published: 09/14/2020, edited: 09/14/2020

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