Famotidine

By Lauren R. Forsythe, PharmD, MBA, DICVP; Rania Gollakner, BS, DVM, MPH

What is famotidine?

Famotidine (brand name: Pepcid®, Apo-Famotidine®) is an H2-receptor antagonist that is used to reduce stomach acid production for conditions such as gastrointestinal ulcers, inflammation of the stomach due to kidney disease or stress, inflammation of the esophagus, or acid reflux.

"Many drugs are commonly prescribed for off-label use in veterinary medicine."

Its use in cats, dogs, and small mammals to treat ulcers is “off label” or “extra label”. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is famotidine given?

  • Famotidine is given by mouth, in the form of a tablet or liquid suspension. It may also be given as an injection in a veterinary hospital. 
  • It should be given on an empty stomach before a meal. If given only once daily, the ideal time is before the first meal of the day. 
  • If your pet vomits when given the medication without food, try giving it with food or a treat.

This medication should take effect within 1 to 2 hours; however, effects may not be noticeable, and laboratory tests may be required to evaluate if the medication is working.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

Famotidine may cause the following side effects:

  • low heart rate (when given by injection)
  • gastrointestinal effects such as vomiting, diarrhea, or lack of appetite 
  • headache
  • dry mouth
  • dry skin
  • low white blood cell count (rare)

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Famotidine should NOT BE USED in pets that are allergic to it.

Famotidine should be USED WITH CAUTION in pets that:

  • are geriatric 
  • have liver, kidney, or heart disease
  • are pregnant or nursing

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with famotidine:

  • azole antifungals
  • cefpodoxime
  • cefuroxime
  • cyclosporine 
  • iron salts

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is any monitoring needed with this medication?

No specific monitoring is required while your pet is taking this medication. Your veterinarian may monitor your pet to be sure that the medication is working.

How do I store famotidine?

  • Famotidine tablets should be stored at room temperature, in a tight container, away from light. 
  • The powder for creating the liquid suspension should be stored in a tight container, in a dry place below 40°C (104°F). 
  • The liquid suspension should be stored at less than 30°C (86°F) and discarded after 30 days. Do not freeze the liquid suspension.
  • Storage instructions for compounded liquid suspensions will vary depending on the preparation. Follow the instructions on the bottle carefully.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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