Pepcid® for dogs (famotidine) is an acid-reducing medication that vets may recommend to treat a variety of GI illnesses. Integrative veterinarian Dr. Julie Buzby discusses how Pepcid works, which conditions vets may use it for, and the dosage, side effects, precautions, and drug interactions.
We’ve all had the unfortunate experience of eating or drinking something that didn’t agree with us. To try to ease the nausea, bloating, and stomachache, we might reach for a bottle of Pepcid® AC.
As it turns out, vets recommend famotidine, the drug sold under the brand name Pepcid, for dogs with some forms of GI upset, too.
However, this doesn’t mean you should decide to give it to your dog on your own. Like other human over-the-counter drugs that get used in animals, it is critical to consult your vet before giving your dog Pepcid.
What is Pepcid for dogs?
Pepcid is the brand name for famotidine, a medication that decreases acid secretion in the stomach to address some causes of GI upset in dogs. Since Pepcid is a human medication, when vets prescribe it for dogs, they are using it “extra-label” or “off-label.” This is not a cause for concern as Pepcid is generally safe and effective for most dogs. (As mentioned above, this doesn’t mean you should give it to your dog without consulting your vet.)
What are the forms of Pepcid?
There are three main famotidine-containing products that might be referred to as “Pepcid.” The brand names are listed here, but remember that they are also available as a generic.
- Pepcid® AC: This is the brand name of the over-the-counter (OTC) formulation. Generic and name-brand products contain 10 mg or 20 mg of famotidine as the active ingredient. When your vet tells you to buy “Pepcid” for your dog, this is the correct product. It is important to pay attention to which strength the vet recommended so you don’t under- or overdose your dog.
- Pepcid® Complete: Also available OTC, this chewable tablet combines 10 mg of famotidine and two antacids (calcium carbonate and magnesium hydroxide). This is NOT a product you typically give dogs.
- Pepcid®: This prescription formulation comes in 20 mg and 40 mg strengths as well as an oral liquid and injectable solution.
Note: The remainder of this article pertains to Pepcid AC and Pepcid, but not Pepcid Complete. For simplicity, we will use the term “Pepcid” to refer to OTC or prescription famotidine.
What does Pepcid do for dogs?
Famotidine works by blocking the histamine-2 (H2) receptor on parietal cells in the stomach, helping to reduce stomach acid levels. During the normal digestive process, the stomach’s parietal cells release gastric acid when the molecule histamine binds to their H2 receptors.
However, H2 blockers like famotidine bind to the H2 receptor instead of histamine. This keeps histamine from binding to the H2 receptors and signaling the parietal cells to release stomach acid. As a result, the stomach contents become less acidic, which can provide relief for the dog.
In simpler terms, imagine the parietal cells as a long line of gumball machines. Normally, when you insert a quarter (histamine) into the slot (H2 receptor) and turn the crank, a gumball (stomach acid) comes out. However, if there is a plug (famotidine) in the quarter slot of some of the gumball machines, then you can’t put the quarter in, and you can’t get the gumball out.
The gumball machines without the famotidine plug still work, but the plugged-up ones don’t, so fewer stomach acid gumballs are coming out overall.
What is famotidine used for in dogs?
Due to its acid-reducing properties, Pepcid has many valuable uses in dogs. Most commonly, veterinarians will prescribe famotidine to treat:
- Esophagitis: Irritation of the lining of the esophagus, which can occur due to contact with stomach acid, swallowing foreign objects, or caustic substances, etc.
- Acid reflux in dogs or gastroesophageal reflux disease (GERD): Stomach acid creeping up into the esophagus and causing damage to the tissue.
- Stomach ulcers in dogs: May develop secondary to kidney failure in dogs, liver disease in dogs, toxin ingestion, certain cancers, infection, stress, or medications like steroids or NSAIDs.
- Gastritis in dogs: Irritation of the stomach lining due to dietary indigestion, infections, toxins, parasites, chronic diseases, cancer, etc.
- Vomiting: Vets sometimes use it in vomiting dogs, but famotidine is not an anti-nausea or anti-vomiting drug. Other medications like Cerenia for dogs are better at addressing the actual nausea and vomiting.
- Parvovirus: Pepcid can be an important part of supportive care, especially in puppies and unvaccinated dogs.
- Diseases that cause persistent nausea or repeated vomiting: Provides supportive care for dogs with kidney disease, cancer, or chronic gastrointestinal diseases.
- Pancreatitis in dogs: May be useful to decrease stomach acidity in dogs with severe pancreatic inflammation.
- Mast cell tumors in dogs: Pepcid, an H2 blocker, may be used in combination with Benadryl for dogs, an H1 blocker, to combat the negative effects of the histamine released by cancerous mast cells.
Should I give my dog Pepcid?
Since Pepcid is available OTC, it might be tempting to try giving it to your dog before contacting the vet. The problem with this approach is that, while Pepcid can be useful for acid reflux, mild GI irritation, and the other conditions above, it isn’t the solution for foreign bodies, systemic diseases that cause GI signs, or a host of other problems. By deciding to try Pepcid before talking to your vet, you might prolong the time before your dog gets a proper diagnosis and treatment.
Thus, if you think your dog could benefit from Pepcid, the best thing you can do is call the vet clinic and let the team know what is going on with him or her. The vet might suggest trying some famotidine and give you a dose that is appropriate for your dog. Or he or she may recommend coming in for an appointment if your dog’s symptoms are concerning or it sounds like a scenario where famotidine is not the right choice.
What is the dosage of famotidine for dogs?
If the vet feels your dog could benefit from famotidine, he or she will determine the dosage based on your dog’s weight, the condition he or she is treating, and your dog’s overall health.
Typically, you will need to give your dog Pepcid once or twice a day (every 12 to 24 hours). Dogs with underlying kidney disease will generally take it once a day since their ability to metabolize medication is often impaired. However, a dog with healthy kidneys may take it twice a day for maximal effect.
Famotidine works best on an empty stomach before your dog’s first meal of the day. But if the initial dose causes nausea or vomiting, you can give it with a small amount of food. That should help decrease medication-related GI upset.
Missed doses
If your dog misses a dose of famotidine, give it as soon as you remember. Then continue with the prescribed dosing schedule. However, if you skip the missed dose, do not double the next scheduled dose for your dog.
Dosage forms and strengths of famotidine
There are a variety of ways your dog may take Pepcid. Sometimes the vet might prescribe famotidine 20 mg or 40 mg tablets through the pharmacy. Other times, he or she will have you pick up some Pepcid at the store. Since OTC famotidine comes in 10 mg and 20 mg tablets, it is important to pay attention to not only the number of tablets the vet wants your dog to take, but also the strength of those tablets.
Safety note: Avoid giving your dog Pepcid in a flavored chewable or rapidly dissolving tablet form. These preparations may contain artificial flavorings, sweeteners (like xylitol, which is toxic for dogs), or dyes that are unsafe for dogs.
For dogs who won’t take pills, the vet may prescribe a famotidine oral suspension (liquid). The medication comes in powder form, which the vet or pharmacist can reconstitute. Famotidine oral suspension is safe to store at room temperature, but you should discard any unused portion after 30 days.
If your dog requires hospitalization, your veterinarian may give Pepcid in an injectable form. This 10mg/mL preparation is reserved for in-clinic use under the direct supervision of your dog’s veterinary care team.
How long does Pepcid take to start working?
Famotidine typically begins to take effect within one to three hours after oral administration. However, if your dog’s symptoms are severe, it may take longer for you to begin seeing improvement.
If at any point it seems like your dog is worsening or not improving, reach out to your vet. This is especially important if you started giving famotidine after talking to your vet, but your dog has not yet been evaluated by the vet.
How long does famotidine last in the body?
Pepcid typically stops working within 24 hours. However, dogs with underlying conditions (such as kidney or liver disease) may metabolize Pepcid more slowly, leading to prolonged effects.
Can dogs take Pepcid long-term?
Pepcid is safe for dogs to take long-term, but it is best suited for short-term use as it tends to lose its efficacy over time. This was demonstrated by a study in the Journal of Veterinary Internal Medicine looking at repeated administration of famotidine in dogs.
In the study, dogs who took famotidine twice daily initially had a good response, as shown by their gastric pH increasing (becoming less acidic). However, by day 12 and 13, the pH of the stomach of dogs taking Pepcid was not significantly different than that of dogs receiving a placebo.
What are the side effects of Pepcid in dogs?
Famotidine is generally well tolerated. But just like people, every dog is different and may respond differently to any new medication. The most common side effects are typically mild, including:
- Vomiting: The dog may be nauseous (drooling and licking lips) or vomiting. Giving Pepcid with a small bit of food can help decrease GI upset.
- Diarrhea: Mild diarrhea is possible.
- Constipation in dogs: On the flip side, some dogs end up constipated instead.
- Lethargy in dogs: Your dog may lie around or sleep more.
- Poor appetite: Sometimes, dogs don’t want to eat as much.
- Dry mouth: This is harder to detect, but your dog might be licking his or her lips due to the mouth feeling funny.
- Injection-site reactions when given in the muscle (IM): The area around the injection may temporarily be sore or inflamed.
If your dog does experience any of these side effects after taking famotidine, contact your veterinarian. He or she can advise you about the next steps.
More serious (but rare) side effects of Pepcid
In rare cases, dogs can experience more serious side effects such as a decreased white blood cell count (agranulocytosis). Affected dogs may be weak, lethargic, or have a poor appetite. And the vet will see decreased white cells on blood tests for dogs.
Additionally, cardiac arrhythmias, decreased heart rate (bradycardia), and sudden vomiting can occur with rapid IV dosing. However, the veterinary team would be the ones administering IV famotidine. Thus, these sorts of side effects are not something you would have to worry about your dog experiencing at home.
What should you expect with a possible famotidine overdose?
Thankfully, famotidine has a very wide margin of safety. This makes it unlikely that a mild to moderate overdose would have dangerous effects. However, much larger overdoses could be problematic. If you suspect that your dog received a significant overdose of Pepcid, contact your vet or a pet poison helpline promptly.
Which dogs should not take famotidine?
As with any medication, there are some situations where famotidine is not recommended. Pregnant or nursing dogs and dogs who are allergic to famotidine should not take it. Additionally, the vet will use famotidine cautiously in senior dogs with concurrent medical conditions, especially those affecting the kidneys and liver.
Which drugs does Pepcid interact poorly with?
It is important to let the vet know if your dog is taking famotidine. Since it alters the pH of the stomach, this may change the absorption of other oral medications.
Drug interactions may occur between famotidine and certain antibiotics (such as cephalosporins), immunosuppressants (cyclosporine), antifungals (such as azole drugs), and supplements (including iron and Vitamin B12). You should give these medications 1-2 hours before famotidine to avoid interfering with their absorption.
Additionally, veterinarians have divided opinions about using famotidine in combination with sucralfate for dogs, a medication that helps coat the stomach lining. It is possible that since famotidine decreases stomach acidity, sucralfate might not work as well.
Some vets avoid giving famotidine and sucralfate together. Others recommend giving sucralfate 30 minutes before famotidine or other acid reducers.
Finally, while not technically a drug, it is worth noting that famotidine may (or may not, depending on the study) interfere with the results of skin testing for dog seasonal allergies. The veterinary dermatologist will let you know what he or she prefers regarding giving famotidine prior to the test.
Alternatives to Pepcid: Omeprazole
Another popular acid-reducing medication that can be an alternative to Pepcid is omeprazole.
However, like famotidine, you should not give your dog omeprazole without talking to your vet.
Famotidine temporarily blocks acid secretion at the level of the H2 receptors, but omeprazole takes it one step further. Omeprazole for dogs is a proton pump inhibitor (PPI). This means it binds to the cellular pumps used for stomach acid production and release. Once it binds to a pump, that pump is out of commission permanently, so the body will have to make a new pump to replace it. This may make omeprazole more effective than Pepcid overall.
It does take longer (2-4 days) for Omeprazole to reach full effect. Thus, the quicker (1-3 hours) onset of Famotidine can be helpful in some conditions. While both Pepcid and omeprazole are safe for long-term use, omeprazole does not seem to lose efficacy when given continuously, like Pepcid does.
Your vet will determine if famotidine, omeprazole, or a different antacid will be right for your dog’s particular situation. Plus, he or she may also recommend anti-nausea medications, bland diet for dogs, sucralfate, or other medications and treatments.
Work with your vet to decide if famotidine is right for your dog
Pepcid is a safe and effective medication to help relieve some types of digestive upset in dogs. But that doesn’t automatically mean you should give it to your dog the next time he or she is vomiting, having diarrhea, or not eating well.
Instead, give your vet a call and let him or her know what is going on with your dog. From there, you and your vet can work together to decide if trying Pepcid, bringing your dog in for an appointment, or something else is the right approach. This sort of partnership is the best way to help your dog start feeling better quickly.
Has your dog taken Pepcid before?
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