Famotidine oral tablet side effects: A detailed guide

Specifically, the Food and Drug Administration (FDA) has approved famotidine oral tablet for use in adults and children to treat:

• duodenal or gastric ulcers short term
• duodenal ulcers long term
• gastroesophageal reflux disease short term
• high stomach acid level caused by certain conditions, including Zollinger-Ellison syndrome, long term

This article describes possible side effects of famotidine oral tablet. You’ll also find information on cost savings and coupon options for famotidine.

Famotidine oral tablet is a generic version of the brand-name drug Pepcid AC. Pepcid AC and certain famotidine strengths are available over-the-counter at a pharmacy without a prescription. This article focuses on prescription-strength famotidine. Famotidine also comes as an injection given into a vein and a liquid suspension (a kind of liquid mixture) that you swallow. But these forms aren’t described in this article. To learn more about these forms, talk with your doctor.

You can explore this overview article to learn more about famotidine oral tablet, including the drug’s uses, dosage, ways to save on cost, and more.

More common side effects of famotidine

Famotidine oral tablet may cause mild or serious side effects. Below are some of the more common side effects of this medication.

Commonly reported side effects of famotidine oral tablet include:

• headache
• dizziness
• constipation
• diarrhea

Mild side effects of famotidine

Famotidine may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.

Mild side effects of famotidine oral tablet that occurred in studies include:

• headache
• dizziness
• constipation
• diarrhea
• upset stomach
• dry mouth
• confusion
• fatigue (low energy)
• weakness
• mild allergic reaction*

* An allergic reaction is possible with famotidine oral tablet. It’s unclear whether it occurred in the drug’s studies, but it has happened since the drug was approved for use. To learn more about this side effect, see the “Side effects of famotidine in detail” section below.

Famotidine oral tablet may cause more mild side effects than those listed above. For details, see the drug’s prescribing information.

Serious side effects of famotidine

Famotidine may cause certain serious side effects. If you have any serious side effects from famotidine oral tablet, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911, or a local emergency number, or go to the nearest emergency room.

After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with famotidine oral tablet.

Serious side effects of famotidine oral tablet that occurred in studies include:

• blood cell problems, including low platelet count and low white blood cell count
• seizure
• long QT syndrome*
• mental health side effects*
• liver problems*
• severe allergic reaction*†

* To learn more about this side effect, see the “Side effects of famotidine in detail” section below.
† An allergic reaction is possible with famotidine oral tablet. It’s unclear whether it occurred in the drug’s studies, but it has happened since the drug was approved for use.

Common questions about side effects of famotidine

Here are answers to some common questions about side effects of famotidine oral tablet. If you have other questions, talk with your doctor or pharmacist.

Can famotidine 20 mg cause different side effects than famotidine 40 mg?

No, different strengths of famotidine aren’t expected to cause different side effects. So, the 20-milligram (mg) strength of famotidine shouldn’t cause different side effects than the 40-mg strength.

Generally, a higher dose of a medication increases your risk of having side effects from it. But it usually doesn’t cause different side effects.

Your pharmacist or doctor can answer more questions you may have about your famotidine dosage and your risk of side effects. (For details about famotidine’s dosage, see this article.)

Does famotidine cause long-term side effects?

It’s not likely. Long-term side effects were not reported in the drug’s studies.

Famotidine’s side effects are usually temporary and easily managed. And they should go away if you stop taking the drug with your doctor’s recommendation.

Tell your doctor if you have side effects that don’t go away or are bothersome. They can suggest other treatments for your condition instead.

Is weight gain a side effect of famotidine?

No, weight gain wasn’t reported as a side effect of famotidine treatment.

Using a proton pump inhibitor (PPI) drug to treat heartburn or acid reflux may cause weight gain. But famotidine isn’t a PPI drug. Examples of PPIs include omeprazole (Prilosec OTC) and esomeprazole (Nexium).

Talk with your doctor if you have questions or concerns regarding your weight while you’re taking famotidine.

If I take famotidine, will I experience kidney-related side effects?

It’s not likely. Kidney-related side effects weren’t reported in the drug’s studies.

But if you have a kidney problem, such as chronic (long-term) kidney disease, you may have an increased risk of certain side effects of famotidine. These include mental health side effects and long QT syndrome (a kind of irregular heart rhythm). To learn more about these side effects, see the “Side effects of famotidine in detail” section below.

If you have questions about kidney-related side effects and famotidine, talk with your doctor.

How do the side effects of prescription famotidine oral tablet compare with those of the over-the-counter form of the drug?

Side effects caused by prescription and over-the-counter (OTC) famotidine are expected to be the same. This is because the drugs contain the same active drug (an ingredient that makes the drug work).

If you have questions about the side effects of prescription or OTC forms of famotidine, talk with your doctor or pharmacist.  

Coupon for famotidine

Visit this page to access Optum Perks coupons and get price estimates for famotidine when you use the coupons. These coupons can provide significant savings on your prescription costs.

Note: Optum Perks coupons cannot be used with any insurance copays or benefits.

Side effects of famotidine in detail

Below you’ll find details on some of the side effects of famotidine oral tablet.

Long QT syndrome

Taking famotidine may rarely cause long QT syndrome. This refers to the lengthening of the QT interval, which is a specific part of your heartbeat. So, long QT syndrome is a kind of irregular heart rhythm.

Often, long QT syndrome won’t cause symptoms. But it’s also possible to experience fatigue (low energy) or tire quickly during physical activity. You may also feel dizzy, lightheaded, weak, or short of breath.

You may have an increased risk of long QT syndrome from taking famotidine, including if you:

• already have long QT syndrome
• have a slow heart rate
• have heart failure
• are age 65 years or older
• take other drugs that can affect your heart’s rhythm
• have low blood potassium or magnesium levels

Ways to manage

Due to this risk, your doctor may avoid prescribing famotidine if you have any of the risk factors described above. But if they do prescribe you famotidine, they’ll closely monitor you throughout your treatment for any signs of an irregular heart rhythm.

If you think you’re having symptoms of long QT syndrome while taking famotidine, contact your doctor immediately. They’ll likely recommend scheduling an appointment so they can check your symptoms in person. Then, they can recommend the best treatment for your symptoms. This may include stopping famotidine and exploring other treatments for your condition.

Mental health effects

Rarely, mental health effects have been reported in people taking famotidine. These are side effects that affect your emotional and psychological well-being. They can also affect how you interact with your environment and other people.

Specific mental health side effects of famotidine include:

• hallucinations (seeing or hearing things that aren’t real)
• feeling disoriented, agitated (restless), or confused
• nightmares
• mania or manic symptoms
• depression or anxiety
• decreased libido (sex drive)
• convulsions in people with existing kidney problems, such as chronic (long-term) kidney disease

These side effects are expected to go away once you stop taking famotidine.

Ways to manage

Immediately contact your doctor if you notice changes in your behavior, thinking, or mood. Also, contact them if you think you’re having any of the side effects above. Your doctor will likely suggest you stop taking famotidine. They can also treat your symptoms depending on the side effect you’re experiencing.

Liver problems

Famotidine treatment has caused liver problems in rare cases. These include increased liver enzyme levels and hepatitis (inflammation of your liver). It also includes a kind of liver disease that reduces or blocks the outflow of bile from your liver.

Symptoms of these liver problems include:

• jaundice (yellowing of your skin or the whites of your eyes)
• fatigue (low energy)
• itchy skin
• pain in the upper right of your belly

Your risk of liver problems from taking famotidine may increase if you have an existing liver problem. This includes alcohol-related liver disease. Taking famotidine could also worsen your liver condition.

Ways to manage

Contact your doctor right away if you develop symptoms of liver problems while taking famotidine. Depending on your symptoms and health history, your doctor may:

• recommend reducing your famotidine dose*
• temporarily or permanently have you stop taking famotidine
• recommend treatment for your liver problems, if necessary

For example, if your doctor has you stop famotidine treatment to take a lower dose, liver enzyme levels often go back to usual. But if you develop liver disease, your doctor may have you stop taking the drug.

* To learn about famotidine’s dosages, see this article.

Allergic reaction

For some people, famotidine oral tablet can cause an allergic reaction. It’s unclear whether it occurred in the drug’s studies, but it has happened since the drug was approved for use.

Symptoms can be mild or serious, and they may include:

• itchiness
• skin rash
• swelling under the skin, usually affecting eyelids, lips, hands, or feet
• swelling of the mouth, tongue, or throat, which can make it hard to breathe
• flushing (temporary warmth, redness, or deepening of skin color)

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know if you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to famotidine oral tablet, your doctor may recommend taking a different medication instead.

Warnings for famotidine

Below are some factors you may want to discuss with your doctor before taking famotidine oral tablet.

Warnings

It may not be safe for you to take famotidine oral tablet if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether famotidine oral tablet is a safe treatment option for you.

Before taking famotidine oral tablet, tell your doctor about your health and medications you take. Things to consider include those listed below.

Heart problems. If you have a heart problem, such as irregular heart rhythm, and take famotidine, your risk of long QT syndrome* may increase. This is a rare but serious side effect of famotidine. To learn more, talk with your doctor. They’ll let you know whether it’s safe for you to take this medication. If they do prescribe famotidine, they’ll likely monitor you closely for signs of irregular heart rhythm.

Mental health conditions. If you have a mental health condition, such as depression, you may have a higher risk of mental health side effects* from famotidine treatment. Taking famotidine could also worsen your condition. For more information, talk with your doctor.

Kidney problems. If you have a kidney problem, such as chronic kidney disease, your doctor may prescribe a lower famotidine dose.† This is because having kidney problems increases your risk of certain side effects from famotidine. These include long QT syndrome* and psychiatric side effects.* To learn more, talk with your doctor.

Liver problems. Taking famotidine can cause liver problems* as a side effect. It can also worsen them if you already have a liver condition. Be sure to tell your doctor if you have liver problems before you start taking famotidine. They’ll determine whether this medication is safe for you to take.

Allergic reaction. If you’ve had an allergic reaction* to famotidine oral tablet or any of its ingredients, your doctor will likely not prescribe this medication. In addition, they’ll also avoid prescribing famotidine if you’ve had an allergic reaction to a similar drug, such as ranitidine. (Both famotidine and ranitidine belong to a group of drugs called histamine-2 receptor blockers.) Ask them about other treatment options that may be better for you.

* For more details about this side effect, see the “Side effects of famotidine in detail” section above.
† To learn about famotidine’s dosages, see this article.

Famotidine and pregnancy

It’s not known whether famotidine is safe to take during pregnancy, as there aren’t enough studies of the drug in pregnant people.

Talk with your doctor to learn more about the risks and benefits of heartburn or acid reflux treatments if you’re pregnant or planning to become pregnant.

Famotidine and breastfeeding

It may not be safe to take famotidine while breastfeeding. Famotidine is known to pass into breast milk. So it may cause side effects in a child who is breastfed.

Due to this risk, your doctor will likely recommend that you avoid breastfeeding. Or they may recommend avoiding famotidine treatment while breastfeeding.

Talk with your doctor to learn more about your options. They can discuss other ways to feed your child or other medications that may treat your condition.

Famotidine and alcohol

Famotidine oral tablet is not known to interact with alcohol.

But keep in mind that alcohol can worsen symptoms of gastroesophageal reflux disease, such as nausea and vomiting. Drinking alcohol may also worsen or increase your risk of heartburn. And famotidine treats both of these conditions.

If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with famotidine oral tablet.

What to ask your doctor

This article describes common and serious side effects of famotidine oral tablet. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.

Here’s a list of some possible questions you may want to ask your doctor:

• How do famotidine’s side effects compare with other medications that treat heartburn?
• If I have side effects from taking famotidine, is there a lower dose you can prescribe?
• If famotidine treatment causes an upset stomach, how can I treat it?

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.