Child dosage (ages 16–17 years)
Famotidine, Oral Tablet
Prescription famotidine oral tablet is available as a generic drug and as a brand-name drug. The brand name is Pepcid. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand-name version.
Prescription famotidine is also available as an oral suspension and an injectable form, which is only given by a healthcare provider. Famotidine is also available as an over-the-counter drug.
Why it’s used
Famotidine is used to relieve symptoms of acid reflux and heartburn. It does this by reducing the amount of acid in your stomach. It treats the following conditions:
- gastroesophageal reflux disease (GERD). GERD happens when acid in your stomach backs up into your esophagus (the tube that connects your mouth to your stomach). This may cause a burning feeling in your chest or throat, a sour taste in your mouth, or burping.
- acid-related damage to the lining of your esophagus
- duodenal ulcers. The duodenal area is the part of your intestine where food passes when it leaves the stomach.
- stomach ulcers
- conditions where your stomach makes too much acid. These conditions include Zollinger-Ellison syndrome.
This drug may be used as part of a combination therapy. This means you may need to take it with other medications.
How it works
Famotidine belongs to a class of drugs called histamine-2 receptor blockers. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
Famotidine works by blocking the histamine 2 (H2) receptor in your stomach. This receptor helps release acid in your stomach. By blocking this receptor, this drug lowers the amount of acid released in your stomach.
Famotidine oral tablet doesn’t cause drowsiness, but it can cause other side effects.
More common side effects
The more common adult side effects for this drug are slightly different from the more common side effects for children.
- Adult side effects can include:
- headache
- dizziness
- constipation
- diarrhea
- agitation, unusual restlessness, or crying for no clear reason
If these effects are mild, they may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.
Serious side effects
Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:
- Heart rate and rhythm problems. Symptoms can include:
- dizziness
- fainting
- shortness of breath
- irregular heart rate and rhythm
- unusual muscle pain that you cannot explain
- weakness
- fever
- agitation
- anxiety
- depression
- trouble sleeping
- seizures
- sexual problems, such as decreased sex drive
- unexplained or unusual weakness
- decrease in appetite
- pain in your abdomen (stomach area)
- change in the color of your urine
- yellowing of your skin or the whites of your eyes
- blisters
- rash
- mouth sores or ulcers
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
Famotidine oral tablet can interact with other medications, vitamins, or herbs you may be taking. An interaction is when a substance changes the way a drug works. This can be harmful or prevent the drug from working well.
To help avoid interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbs you’re taking. To find out how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.
Famotidine oral tablet comes with several warnings.
Allergy warning
Famotidine can cause a severe allergic reaction. Symptoms can include:
- trouble breathing
- swelling in your eye(s) or face
- swelling of your throat or tongue
- rash
- hives
If you have an allergic reaction, call your doctor or local poison control center right away. If your symptoms are severe, call 911 or go to the nearest emergency room.
Don’t take this drug again if you’ve ever had an allergic reaction to it or other histamine receptor blockers (such as cimetidine, ranitidine, or nizatidine). Taking it again could be fatal (cause death).
Warnings for people with certain health conditions
For people with moderate or severe kidney disease: If you have kidney problems, you may not be able to clear this drug from your body. This may increase the levels of this drug in your body. The increased levels may cause more side effects, such as confusion and an irregular heart rhythm called QT prolongation.
Warnings for other groups
For pregnant women: Famotidine is a category B pregnancy drug. That means two things:
- Research in animals has not shown a risk to the fetus when the mother takes the drug.
- There aren’t enough studies done in humans to show if the drug poses a risk to the fetus.
Talk to your doctor if you’re pregnant or planning to become pregnant. Animal studies do not always predict the way humans would respond. Therefore, this drug should only be used in pregnancy if clearly needed.
For women who are breastfeeding: Famotidine may pass into breast milk and may cause side effects in a child who is breastfed. Talk to your doctor if you breastfeed your child. You may need to decide whether to stop breastfeeding or stop taking this medication.
For seniors: The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects.
For children:
- Famotidine can be used in children of all ages for the treatment of gastroesophageal reflux disease (GERD).
- This drug hasn’t been studied in children under 1 year of age for the treatment of ulcers.
- This drug hasn’t been studied in children under 16 years of age for the treatment of pathological hypersecretory conditions.
This dosage information is for famotidine oral tablet. All possible dosages and drug forms may not be included here. Your dosage, drug form, and how often you take the drug will depend on:
- your age
- the condition being treated
- how severe your condition is
- other medical conditions you have
- how you react to the first dose
Forms and strengths
Brand: Pepcid
Generic: famotidine
Dosage for duodenal ulcer
Adult dosage (ages 18 years and older)
- Short-term dose: 40 mg taken once per day at bedtime for up to 4 weeks. Your doctor may divide your dose into 20 mg taken two times per day.
- Long-term dose: 20 mg taken once per day at bedtime.
Child dosage (age 17 years)
- Short-term dose: 40 mg taken once per day at bedtime for up to 4 weeks. Your doctor may divide your dose into 20 mg taken two times per day.
- Long-term dose: 20 mg taken once per day at bedtime.
Child dosage (ages 1–16 years)
- Dose: 0.5 mg/kg of body weight per day, up to 40 mg per day. You’ll take either one dose at bedtime or 2 equally divided doses per day.
- Dose changes: Your doctor may increase your dose and length of treatment based on how well you respond to the drug. They may increase your dose up to 1 mg/kg per day.
Child dosage (under 1 year of age)
This drug hasn’t been studied in children under 1 year of age for the treatment of this condition.
Senior dosage (ages 65 years and older)
The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
Special considerations
People with moderate or severe kidney disease: Your doctor may decrease your dose of this drug by half. Or they may have you take one dose every 36–48 hours instead of every day.
Dosage for gastric ulcer
Adult dosage (ages 18 years and older)
- Short-term dose: 40 mg taken once per day at bedtime.
Child dosage (age 17 years)
- Short-term dose: 40 mg taken once per day at bedtime for up to 4 weeks. Your doctor may divide your dose into 20 mg taken two times per day.
- Long-term dose: 20 mg taken once per day at bedtime.
Child dosage (ages 1–16 years)
- Dose: 0.5 mg/kg of body weight per day, up to 40 mg per day. You’ll take either one dose at bedtime or 2 equally divided doses per day.
- Dose changes: Your doctor may increase your dose and length of treatment based on how well you respond to the drug. They may increase your dose up to 1 mg/kg per day.
Child dosage (under 1 year of age)
This drug hasn’t been studied in children under 1 year of age for the treatment of this condition.
Senior dosage (ages 65 years and older)
The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
Special considerations
People with moderate or severe kidney disease: Your doctor may decrease your dose of this drug by half. Or they may have you take one dose every 36–48 hours instead of every day.
Dosage for gastroesophageal reflux disease
Adult dosage (ages 18 years and older)
- Gastroesophageal reflux disease (GERD) symptoms: 20 mg taken two times per day for up to 6 weeks.
- Esophagitis (irritated esophagus with sores) with GERD symptoms: 20–40 mg taken two times per day for up to 12 weeks.
Child dosage (age 17 years)
- Gastroesophageal reflux disease (GERD) symptoms: 20 mg taken two times per day for up to 6 weeks.
- Esophagitis (irritated esophagus with sores) with GERD symptoms: 20–40 mg taken two times per day for up to 12 weeks.
Child dosage (age 1–16 years)
- Dose: 1 mg/kg of body weight per day. You’ll take this as one dose or in 2 equally divided doses per day, up to 40 mg taken twice per day.
- Dose changes: Your doctor may increase your dose and length of treatment based on how well you respond to the drug. They may increase your dose up to 2 mg/kg per day.
Child dosage (ages 3 months to 1 year)
Dose: 0.5 mg/kg of body weight given twice per day for up to 8 weeks
Child dosage (ages 0–3 months)
Dose: 0.5 mg/kg of body weight given once per day for up to 8 weeks
Senior dosage (ages 65 years and older)
The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
Special considerations
People with moderate or severe kidney disease: Your doctor may decrease your dose of this drug by half. Or they may have you take one dose every 36–48 hours instead of every day.
Dosage for pathological hypersecretory conditions
Adult dosage (ages 18 years and older)
- Typical starting dose: 20 mg taken every 6 hours.
- Dose increases: Your doctor may increase your dose based on your symptoms.
- Maximum dose: People with severe disease may need 160 mg taken every 6 hours.
Child dosage (ages 16–17 years)
- Typical starting dose:20 mg taken every 6 hours.
- Dose increases: Your doctor may increase your dose based on your symptoms.
- Maximum dose: People with severe disease may need 160 mg taken every 6 hours.
Child dosage (under 0–15 years)
This drug hasn’t been studied in children under 16 years of age for the treatment of this condition.
Senior dosage (ages 65 years and older)
The kidneys of older adults may not work as well as they used to. This can cause your body to process drugs more slowly. As a result, more of a drug stays in your body for a longer time. This raises your risk of side effects. Your doctor may start you on a lowered dose or a different dosing schedule. This can help keep levels of this drug from building up too much in your body.
Special considerations
People with moderate or severe kidney disease: Your doctor may decrease your dose of this drug by half. Or they may have you take one dose every 36–48 hours instead of every day.
Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Famotidine oral tablet is used for long-term treatment of Zollinger-Ellison syndrome and maintaining healing of ulcers. Famotidine oral tablet is used for short-term treatment of gastroesophageal reflux disease (GERD) and duodenal and gastric ulcers. Famotidine comes with risks if you don’t take it as prescribed.
If you stop taking the drug suddenly or don’t take it at all: Your acid reflux, heartburn, or ulcer symptoms may not get better or may get worse.
If you miss doses or don’t take the drug on schedule: Your medication may not work as well or may stop working completely. For this drug to work well, a certain amount needs to be in your body at all times.
If you take too much: You could have dangerous levels of the drug in your body. Symptoms of an overdose of this drug can include:
- agitation
- confusion
- seizures
- severe muscle pain
If you think you’ve taken too much of this drug, call your doctor or local poison control center. If your symptoms are severe, call 911 or go to the nearest emergency room right away.
What to do if you miss a dose: Take your dose as soon as you remember. But if you remember just a few hours before your next scheduled dose, take only one dose. Never try to catch up by taking two doses at once. This could result in dangerous side effects.
How to tell if the drug is working: You should have less pain and your symptoms should improve.
Keep these considerations in mind if your doctor prescribes famotidine oral tablet for you.
General
- You can take famotidine with or without food.
- Take this drug at the time(s) recommended by your doctor.
- You can cut or crush the tablet.
- Not every pharmacy stocks this drug. When filling your prescription, be sure to call ahead.
Storage
- Store the oral tablets at 77°F (25°C). They may be stored for a short time from 59°F to 86°F (15°C to 30°C). Keep them away from light.
- Don’t store this medication in moist or damp areas, such as bathrooms.
Refills
A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.
Travel
When traveling with your medication:
- Always carry your medication with you. When flying, never put it into a checked bag. Keep it in your carry-on bag.
- Don’t worry about airport x-ray machines. They can’t hurt your medication.
- You may need to show airport staff the pharmacy label for your medication. Always carry the original prescription-labeled box with you.
- Don’t put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.
Your diet
Certain foods and beverages may irritate your stomach. This irritation could make your symptoms worse. Your doctor may suggest that you avoid spicy, acidic, and fatty foods while you take this drug. (Acidic foods include tomatoes and citrus fruits.) They may also ask you to avoid beverages with caffeine.
Insurance
Many insurance companies require a prior authorization for this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.
There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.
Disclaimer: Healthline 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 other 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.
Last medically reviewed on January 13, 2016
How we reviewed this article:
Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.
- Pepcid – famotidine powder, for suspension. (2011, October)
dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4f1a0b58-f7c8-485e-a317-432e1c374d2f - Pepcid – famotidine tablet, film coated. (2014, February)
dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=76be6dfc-d06b-4f91-a895-6dade0e14fe3
Famotidine
Medically reviewed by Sanjai Sinha, MD. Last updated on Sep 30, 2021.
What is famotidine?
Famotidine is a histamine-2 blocker that works by decreasing the amount of acid the stomach produces.
Famotidine is used to treat and prevent ulcers in the stomach and intestines. It also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome.
Famotidine also treats gastroesophageal reflux disease (GERD) and other conditions in which acid backs up from the stomach into the esophagus, causing heartburn.
The Zantac 360 brand of this medicine does not contain ranitidine, a medicine that was withdrawn from market in the United States.
Warnings
Before taking famotidine, tell your doctor if you have kidney or liver disease, a history of Long QT syndrome, stomach cancer or other problems, or asthma, COPD, or other breathing problems.
Famotidine may be only part of a complete program of treatment that also includes changes in diet or lifestyle habits. Follow your doctor’s instructions very closely.
Heartburn is often confused with the first symptoms of a heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, pain spreading to the jaw, arm or shoulder, nausea, sweating, anxiety, light-headedness and a general ill feeling.
Related/similar drugs
Before taking this medicine
You should not use this medicine if you are allergic to famotidine or similar medicines such as ranitidine (Zantac), cimetidine (Tagamet), or nizatidine (Axid).
To make sure this medicine is safe for you, tell your doctor or pharmacist if you have ever had:
- kidney disease;
- liver disease;
- cancer stomach; or
- long QT syndrome (in you or a family member).
Ask a doctor before using famotidine if you are pregnant or breastfeeding.
How should I take famotidine?
Use famotidine exactly as directed on the label, or as prescribed by your doctor.
Famotidine oral is taken by mouth.
Famotidine injection is given as an infusion into a vein. A healthcare provider will give you this injection if you are unable to take the medicine by mouth.
You may take famotidine oral with or without food.
Shake the bottle of Pepcid suspension (liquid) vigorously for 5 to 10 seconds prior to each use. Measure the liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).
Most ulcers heal within 4 weeks of treatment, but it may take up to 8 weeks of using this medicine before your ulcer heals. Keep using the medication as directed.
Call your doctor if the condition you are treating with this medicine does not improve, or if it gets worse while using this medicine.
Famotidine may be only part of a complete program of treatment that also includes changes in diet or lifestyle habits. Follow all instructions of your doctor or dietitian.
Store at room temperature away from moisture, heat, and light. Do not allow the liquid medicine to freeze.
Throw away any unused liquid that is older than 30 days.
What happens if I miss a dose?
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What to avoid
Avoid drinking alcohol. It can increase the risk of damage to your stomach.
Avoid taking other stomach acid reducers unless your doctor has told you to. However, you may take an antacid (such as Maalox, Mylanta, Gaviscon, Milk of Magnesia, Rolaids, or Tums) with famotidine.
Famotidine side effects
Get emergency medical help if you have any signs of an allergic reaction to famotidine: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using this medicine and call your doctor at once if you have:
- confusion, hallucinations, agitation, lack of energy;
- a seizure;
- fast or pounding heartbeats, sudden dizziness (like you might pass out); or
- unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.
Some side effects may be more likely in older adults and in people who have severe kidney disease.
Common famotidine side effects may include:
- headache;
- dizziness; or
- constipation or diarrhea.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will interact with famotidine?
Famotidine oral can make it harder for your body to absorb other medicines you take by mouth. Tell your doctor if you are taking:
- cefditoren;
- dasatinib;
- delavirdine;
- fosamprenavir; or
- tizanidine (if you are taking famotidine liquid).
This list is not complete. Other drugs may interact with famotidine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
Popular FAQ
How long does it take for famotidine to work?
Famotidine starts to block stomach acid within 15 minutes to 1 hour of taking the medicine. The maximum effect usually occurs within 1 to 3 hours, and lasts for 10 to 12 hours after a single dose. It will also work to prevent heartburn if taken 10 to 60 minutes before a meal. Do not take more than 2 tablets in 24 hours.
Is it better to take famotidine in the morning or at night?
In general, you can take over-the-counter (OTC) famotidine (Pepcid AC, Zantac 360) at any time of the day or night to help treat heartburn symptoms. Studies have shown it is best to take OTC famotidine 1 hour before an evening meal to help prevent heartburn and indigestion in the evening and during bedtime which may interfere with your sleep. Talk to your healthcare provider if your symptoms are severe or ongoing after 14 days.
How much famotidine can I take in one day?
The maximum daily dose of over-the-counter (OTC) famotidine (Pepcid AC, Zantac 360) in adults and children over 12 years of age is 40 mg per day unless your doctor prescribes it otherwise. If your symptoms persist more than 2 weeks, contact your doctor. Higher doses may be used for other conditions such as erosive esophagitis or Zollinger-Ellison Syndrome.
Famotidine is usually the first choice to treat occasional heartburn if your symptoms occur less than two times per week. It can be used as needed, provides quick relief (within 15 to 30 minutes), and is usually less expensive than omeprazole. Omeprazole may be an option if your heartburn occurs two or more days per week. Both products are available without a prescription. Continue reading
Famotidine (brand name: Pepcid AC, Zantac 360) should not be used for longer than 14 days if you are treating heartburn symptoms. Famotidine may be used for a longer period under the direction of your healthcare provider for treatment of intestinal or stomach ulcers, gastroesophageal reflux (GERD), erosive esophagitis, or other acid-related conditions. Continue reading
Yes, you could take omeprazole in the morning and famotidine at night but there are not many studies investigating this approach. Preliminary results suggest that taking your medication this way may provide superior control of gastric acid secretion at night without compromising the effectiveness of omeprazole in the morning. More research is needed. Continue reading
More about famotidine
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