Famotidine for allergies: Does it work?

Key takeaways

Famotidine, a common heartburn treatment, is also sometimes used to treat allergies—specifically hives—when traditional H1 antihistamines do not provide relief.
Histamines play a crucial role in allergic reactions, and famotidine reduces symptoms by blocking H2 histamine receptors, which are primarily found in the stomach.
While effective for some allergy symptoms, famotidine is not usually the first line of treatment. You should use it in conjunction with other medications under the guidance of a healthcare professional.
Famotidine can cause side effects ranging from mild, such as headaches and dizziness, to severe, including seizures and irregular heart rhythms, and its dosage needs careful adjustment for individuals with kidney problems.

Hives, a scratchy throat, constant sneezing, and itchy eyes are all common allergy symptoms. The trigger could be many things: a bee sting, a new medication, pollen in the air, or an accidental peanut in your cookie.

Even though more than 50 million people in the U.S. deal with allergies yearly, there is no permanent cure—just treatments to help ease the symptoms. Luckily, many medications are available to help manage the symptoms. But that’s not all, there’s even a medicine not intended for allergies that provides additional relief: generic famotidine, or Pepcid.

What is famotidine?

Before explaining famotidine, it’s important to understand how allergy attacks happen. Histamines are made by the immune system and play a key role in getting unwanted allergens out of your system, like pet dander or mold spores. The histamines then interact with histamine receptors, which play a part in your body’s response and many symptoms associated with allergies. There have been four types of histamine receptors identified in the human body: H1, H2, H3, and H4.

Now back to famotidine. What is this medicine exactly?

“Famotidine is an H2 blocker, a type of histamine receptor antagonist,” explains Michael Pistiner, MD, with the Asthma and Allergy Foundation of America (AAFA). “It is most commonly used to treat stomach issues like heartburn, gastroesophageal reflux, and ulcers.”

H2 receptors are found in the stomach. When these receptors are blocked by famotidine, there is less production of stomach acid, which leads to less heartburn and reflux symptoms.

Famotidine for allergies

“What we think of as more traditional antihistamines such as Benadryl (diphenhydramine) and Zyrtec (cetirizine) are H1 antihistamines,” says Robert Sporter, MD, a physician at ENT and Allergy Associates in New York. “H2 antihistamines are much better at treating heartburn than allergies. We use them when we need a little something else to add to an H1 antihistamine.”

So you may be wondering, does famotidine help with allergies? Famotidine is often given when a patient has urticaria, better known as hives. But, famoidine is not typically considered a first treatment option. Patients are given famotidine when hives do not respond to traditional H1 antihistamines. Studies have also shown that famotidine can help treat itchiness associated with hives.

Dr. Sporter gave specific examples of when famotidine treatment may be used: “We may have a patient with daily hives that are not controlled on higher than usual doses of Allegra (fexofenadine) or Zyrtec, so we add famotidine, sold typically as Pepcid. Sometimes emergency department physicians will give famotidine when patients have an allergic reaction, again in addition to H1 antihistamines and often steroids.”

So while famotidine can help treat allergies in some special cases, it’s not commonly used and is never used as the first or only medication.

Famotidine side effects

Like with all medications, there are side effects associated with famotidine. Common side effects include:

Headache
Dizziness
Constipation or diarrhea

While less common, more serious side effects rarely occur, including:

Seizures
Irregular heart rhythm
Confusion
Serious allergic reaction

If you experience these serious side effects, seek emergency medical attention immediately.

Who should not take famotidine for allergies?

For the majority of individuals, famotidine is safe to take. However, there are some considerations. “It can interact with other medications, so discussing with a doctor or pharmacist is important,” says Dr. Pistiner. “People with kidney problems and other chronic conditions should discuss this with their healthcare provider.“ Famotidine is metabolized by the kidneys, so kidney insufficiency, failure or hemodialysis patients need their famotidine dosage changed.

RELATED: Famotidine alternatives

Famotidine for allergies dosage

According to Dr. Sporter, the dosage for famotidine will depend on if you have a prescription or not: “Famotidine is available over the counter in 10 and 20 mg tablets for adults given twice a day,” he says. “In prescription form it comes in a liquid for children, and 40 mg tablets given once daily.“ Famotidine is available in oral forms: both suspension and tablets. It is also available by an intravenous medication formulation. The FDA has approved famotidine for infants 3 months of age through adulthood.

When purchasing this drug, you can get the generic famotidine or opt for the name-brand Pepcid. With whichever one you buy, effects may be evident within an hour, but the maximum effect will be felt in one to three hours and usually last up to 12 hours.

How much does famotidine cost?

The cost of famotidine varies on a few factors: the formulation and dosage, your insurance, and if you use a coupon. For 30, 20 mg tablets, famotidine will cost $36.28 without insurance, but with a SingleCare coupon, you could pay as little as $5.74. If you go for the same amount and dosage with the name brand Pepcid, the cost could be upward of $400 without insurance.