How much famotidine can I give my dog?

In this article:

• Famotidine dose for dogs
• How much famotidine can I give my dog?
• Interactions
• Guidelines for administration

In this article

• Famotidine dose for dogs
• How much famotidine can I give my dog?
• Interactions
• Guidelines for administration

Famotidine is an over-the-counter acid reducer. Better known as the brand-name Pepcid AC, this drug suppresses stomach acid by blocking histamine receptors on the stomach lining. Most people think of it as a heartburn or acid reflux remedy, but according to Plumb’s, veterinarians use it to treat or prevent more serious digestive system issues like ulcers, gastritis, esophagitis, and, yes, acid reflux. In veterinary medicine, the standard famotidine dosage for dogs ranges from 0.25 to 0.5 mg per pound of body weight, but this can vary depending on the type and severity of the condition being treated. Famotidine is safe for dogs, but pet caregivers should have a veterinarian examine the dog if it’s experiencing gastrointestinal distress before giving it store-bought medications. 

RELATED: Famotidine (Pepcid) for dogs

Famotidine dosage for dogs

The Merck Veterinary Manual says a typical famotidine dosage for dogs is 0.5–1 mg per kilogram (mg/kg) given once daily, which is around 0.25–0.5 mg per pound. However, the dose of famotidine is determined by the dog’s weight and the condition being treated, according to Dr. Amy Attas, DVM, veterinarian and author of Pets and the City: True Tales of a Manhattan House Call Veterinarian. For example, “for decreasing gastric secretion, the dose is lower; it is calculated at 0.1mg/pound of weight twice daily,” she says. “For more serious conditions, such as gastric ulceration, the dose starts at 1 mg/pound, and it would be given intravenously.”

Here’s what Plumb’s Veterinary Drug Handbook recommends for other conditions:

• To reduce stomach acid concentrations: 0.1–0.5 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 to prevent/treat ulcers associated with mast cell tumors: 0.5 mg/kg every 24 hours
• As an add-on treatment for gastrointestinal problems due to chronic kidney disease, 0.5 mg/kg given orally once per day

How much famotidine can I give my dog?

In humans, famotidine is typically a short-term treatment because it can rapidly lose efficacy with repeated dosing. This happens both in humans and dogs. For people, the prescribing information advises that its continual use be limited to four to six weeks. There’s rarely a reason to take it for more than 6 to 8 weeks. Dr. Attas says long-term use (over 14 days) can decrease famotidine’s efficacy in dogs, as well, and “there are other medications that provide better gastric acid suppression (e.g., omeprazole) that can be used long-term without a decrease in efficacy.”

If the dog’s symptoms persist for more than a few weeks, contact the vet for next steps. “Continuous monitoring by a veterinarian is crucial to determine the appropriate duration of famotidine therapy for each dog,” says Dr. Sabrina Kong, DVM, a Staff Veterinarian Writer at WeLoveDoodles.

Based on the average 0.25–0.5 mg/pound dosage, here’s how much famotidine may work for dogs. Remember, it depends on the condition, and always follow the vet’s instructions. Also, watch for symptoms of famotidine overdose, which include diarrhea, vomiting, and pale gums. 

Famotidine for dogs dosage chart
Weight	Dosage
Under 10 lbs	2.5 mg
10-19 lbs	5 mg
20-29 lbs	10 mg
30-39 lbs	15 mg
40-59 lbs	20 mg
60-79 lbs	30 mg
80-100 lbs	40 mg
101-119 lbs	50 mg
120 lbs and over	60 mg

Does famotidine interact with any other dog medications?

Famotidine is generally safe when administered in the proper dose, “but it can interact with other medications, potentially altering their effects,” says Dr. Kong. “For example, its action on stomach acidity can affect the absorption of certain drugs.” These drug interactions include:

• Azole antifungals: Because famotidine reduces gastric acid, it can also reduce the effectiveness of ketoconazole, itraconazole, and other antifungals.
• Certain antibiotics: Like antifungals, famotidine can decrease the absorption of cefpodoxime and cefuroxime by decreasing stomach acid production.
• Iron salts: Decreased gastric acid secretion can also decrease the rate of iron absorption.
• Antacids: Antacids can decrease the rate of famotidine absorption when taken at the same time.

Tell the vet if your dog is taking any of these medications before administering the famotidine tablets.

Other famotidine precautions

Famotidine and other H2-receptor antagonists, such as Tagamet (cimetidine), are pretty safe for dogs under most circumstances. Still, it’s best to inform the vet if your dog has heart, kidney, or liver disease or is taking other drugs or supplements. Also, use caution when administering famotidine to a senior, pregnant, or nursing dog.

In rare cases, dogs may also have an allergic reaction to famotidine. Contact your veterinarian immediately if you notice a rash, fever, facial swelling, or trouble breathing.

Guidelines for administering famotidine in dogs

“Famotidine can be administered orally, with or without food. However, administering the medication without food may enhance its effectiveness in reducing stomach acid,” says Dr. Kong. Once a dog eats, it can stimulate gastric activity, potentially reducing the drug’s effectiveness, so it’s usually best to administer the drug on an empty stomach before the dog’s first meal of the day. Nevertheless, if the dog shows signs of upset stomach, vomiting, or other digestive issues, try giving the medication with food or a treat.

Treats can also be a good motivator, according to Dr. Attas. If your dog doesn’t want to take famotidine, “The pill can be hidden in a favorite treat, peanut butter, cream cheese, or other sticky, flavorful substance,” she says.

Some dogs may refuse to take a famotidine tablet on their own, either with or without treats, so you might have to administer it by hand. Sit the dog in a comfortable spot, then gently grab the top of their muzzle and tilt their head toward the ceiling, which should open their mouth slightly. Use the other hand to put the pill as far back on the dog’s tongue as possible, then close their mouth and lower their head back to a normal position. You can encourage swallowing by massaging the dog’s throat or blowing on their nose.

If you miss a dose, just administer it as soon as you can, then give the next dose as scheduled. Never give a double dose to make up for a missed dose. Don’t stop the treatment until the vet says it’s okay, since this can cause the dog’s stomach to rebound by overproducing acid.

Store famotidine at room temperature.

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