What is famotidine and how does it work for acid reflux. How to take famotidine tablets for heartburn relief. What are the potential side effects and precautions when using famotidine. When should you see a doctor for GERD symptoms.

Understanding Famotidine: An H2 Blocker for Acid Reflux

Famotidine is a medication classified as an H2 receptor antagonist, commonly known as an H2 blocker. It is widely used to treat and prevent symptoms associated with excess stomach acid production, such as heartburn and acid reflux. By reducing the amount of acid produced in the stomach, famotidine helps alleviate discomfort and protect the digestive tract from potential damage.

How does famotidine work?

Famotidine works by targeting specific cells in the stomach lining called parietal cells. These cells contain H2 histamine receptors, which, when activated, trigger the production of stomach acid. Famotidine blocks these receptors, effectively preventing the stimulation of acid production. This mechanism of action makes famotidine an effective tool in managing conditions related to excessive stomach acid.

What conditions can famotidine treat?

• Gastroesophageal reflux disease (GERD)
• Acid reflux
• Heartburn
• Duodenal ulcers
• Gastric ulcers
• Zollinger-Ellison syndrome

Famotidine for GERD: Dosage and Administration

For those suffering from GERD or frequent heartburn, famotidine can provide much-needed relief. The medication is available both over-the-counter and by prescription, with different strengths and recommendations for use.

Over-the-counter famotidine dosage

For adults and children 12 years or older, the typical dosage for over-the-counter famotidine is:

• 20 mg tablet once or twice daily
• Can be taken at the onset of symptoms or 10-60 minutes before consuming trigger foods or drinks
• Should not exceed two tablets within a 24-hour period

Is famotidine safe for children under 12? It’s important to consult a doctor before administering famotidine to children under 12 years of age. The appropriate dosage and safety considerations may vary depending on the child’s age, weight, and specific condition.

Prescription famotidine for GERD

When prescribed by a doctor for GERD treatment, the dosage and duration of famotidine use may differ from over-the-counter recommendations. Always follow your healthcare provider’s instructions regarding prescription famotidine use.

Maximizing the Effectiveness of Famotidine

To get the most benefit from famotidine, it’s essential to use it correctly and understand its limitations. Here are some tips for maximizing its effectiveness:

1. Take famotidine with a full glass of water
2. Do not chew the tablet; swallow it whole
3. For prevention, take the medication before consuming known trigger foods or drinks
4. Be consistent with timing if taking famotidine regularly
5. Do not exceed the recommended dosage

How long does it take for famotidine to work? Famotidine typically begins to work within an hour of taking it. However, the full effect may not be noticeable for several hours. For optimal prevention of symptoms, it’s best to take famotidine about an hour before potential trigger situations.

Potential Side Effects and Precautions

While famotidine is generally well-tolerated, like all medications, it can cause side effects in some individuals. Being aware of these potential effects and taking necessary precautions can help ensure safe and effective use of the medication.

Common side effects of famotidine

• Headache
• Dizziness
• Constipation or diarrhea
• Nausea
• Fatigue

These side effects are usually mild and may resolve on their own. However, if they persist or worsen, it’s important to consult your healthcare provider.

When to seek medical attention

Certain symptoms may indicate a more serious reaction to famotidine and require immediate medical attention. These include:

• Itching, swelling, or hives
• Rash
• Hoarseness
• Difficulty breathing or swallowing

Can famotidine cause allergic reactions? While rare, some individuals may experience allergic reactions to famotidine. If you have a known allergy to famotidine or other acid-reducing medications, avoid using this drug and consult your doctor for alternative treatments.

Interactions and Contraindications

Famotidine can interact with other medications and supplements, potentially altering their effectiveness or increasing the risk of side effects. It’s crucial to inform your healthcare provider about all the medications and supplements you’re taking before starting famotidine.

Medications that may interact with famotidine

• Certain antifungal medications
• Some antiretroviral drugs used to treat HIV
• Atazanavir
• Dasabuvir
• Erlotinib
• Metformin

Should famotidine be taken with other heartburn medications? Generally, it’s not recommended to combine famotidine with other heartburn medications unless specifically advised by your doctor. Doing so may increase the risk of side effects or lead to overtreatment of your condition.

Long-Term Use of Famotidine: Benefits and Risks

While famotidine can be highly effective for short-term relief of acid reflux symptoms, long-term use should be approached with caution and under medical supervision. Understanding the potential benefits and risks of extended famotidine use can help inform decisions about treatment strategies for chronic GERD.

Benefits of long-term famotidine use

• Consistent relief from acid reflux symptoms
• Reduced risk of esophageal damage from chronic acid exposure
• Improved quality of life for those with persistent GERD

Potential risks of prolonged use

• Increased risk of certain infections due to reduced stomach acid
• Potential for vitamin B12 deficiency
• Possible increased risk of bone fractures in some populations
• Rare but potential risk of kidney problems

Is it safe to use famotidine indefinitely? While famotidine is generally considered safe for long-term use, it’s important to have regular check-ups with your healthcare provider to monitor for any potential side effects or complications. Your doctor may recommend periodic breaks from the medication or alternative treatments based on your individual health needs.

Famotidine vs. Other Acid Reflux Treatments

Famotidine is just one of several options available for treating acid reflux and GERD. Understanding how it compares to other treatments can help you and your healthcare provider determine the most appropriate approach for your specific situation.

Famotidine vs. proton pump inhibitors (PPIs)

Proton pump inhibitors, such as omeprazole and esomeprazole, are another class of medications used to reduce stomach acid production. Compared to famotidine:

• PPIs generally provide stronger and longer-lasting acid suppression
• PPIs may be more effective for severe GERD or for healing esophageal erosions
• Famotidine typically works faster but for a shorter duration
• Famotidine may have fewer long-term side effects than PPIs

Famotidine vs. antacids

Antacids, such as calcium carbonate or magnesium hydroxide, work differently from famotidine:

• Antacids neutralize existing stomach acid, while famotidine prevents acid production
• Antacids provide faster relief but for a shorter duration
• Famotidine is generally more effective for preventing symptoms before they start

Which acid reflux treatment is best? The most appropriate treatment depends on the severity and frequency of your symptoms, as well as your overall health. For occasional heartburn, antacids or famotidine may be sufficient. For more frequent or severe symptoms, a combination of treatments or prescription-strength medications may be necessary. Always consult with your healthcare provider to determine the best treatment plan for your individual needs.

Lifestyle Modifications to Complement Famotidine Treatment

While famotidine can be highly effective in managing acid reflux symptoms, combining medication with lifestyle changes can lead to even better outcomes. Implementing these modifications alongside famotidine use can help reduce the frequency and severity of GERD symptoms.

Dietary changes

• Avoid trigger foods such as spicy, fatty, or acidic foods
• Eat smaller, more frequent meals
• Avoid eating close to bedtime
• Limit alcohol and caffeine consumption

Lifestyle adjustments

• Maintain a healthy weight
• Quit smoking
• Elevate the head of your bed
• Wear loose-fitting clothing around the waist
• Practice stress-reduction techniques

How can lifestyle changes enhance the effectiveness of famotidine? By reducing factors that contribute to acid reflux, lifestyle modifications can help famotidine work more effectively. This combined approach may allow for better symptom control and potentially reduce the need for higher doses or additional medications.

When to See a Doctor for GERD Symptoms

While famotidine can be an effective over-the-counter treatment for occasional heartburn and mild GERD symptoms, there are situations where professional medical advice is necessary. Recognizing when to seek help can prevent complications and ensure appropriate treatment.

Signs that indicate a need for medical attention

• Persistent heartburn symptoms lasting more than two weeks despite using famotidine
• Difficulty or pain when swallowing
• Unexplained weight loss
• Chest pain or pressure (which could indicate a heart problem)
• Persistent nausea or vomiting
• Blood in vomit or stools
• Severe or frequent night-time reflux

Can GERD symptoms indicate a more serious condition? In some cases, what appears to be GERD may be a sign of a more serious underlying condition, such as Barrett’s esophagus, esophageal cancer, or even heart disease. If you experience persistent or worsening symptoms, or if over-the-counter treatments like famotidine are not providing relief, it’s crucial to consult with a healthcare professional for a proper evaluation and diagnosis.

Diagnostic tests for GERD

If your doctor suspects GERD or a related condition, they may recommend one or more of the following diagnostic tests:

• Upper endoscopy
• Esophageal pH monitoring
• Esophageal manometry
• Barium swallow radiograph

These tests can help determine the severity of your condition and guide treatment decisions, which may include prescription-strength medications, lifestyle modifications, or in some cases, surgical interventions.

Famotidine: An h3 Blocker That Relieves Heartburn Fast

Famotidine is an ingredient found in medications that prevent and lessen heartburn symptoms. When you take famotidine, your stomach makes less acid, which helps stop heartburn from occurring.

What Is Famotidine Used For?

Stomach acid contains enzymes and other molecules that help digest food¹. However, when too much acid is produced, it can damage the stomach or other digestive organs, leading to several conditions.

Famotidine, when prescribed by a doctor, can be used to treat²:

Acid reflux is a condition that occurs when stomach acid and undigested food flow back out of your stomach and into your esophagus, the tube that connects your mouth and stomach. When acid reflux happens regularly, it is called GERD. Heartburn is a symptom of acid reflux. It is characterized by a burning sensation in the chest.

Non-prescription famotidine can be used to:

How Does Famotidine Work?

Stomach acid is made by parietal cells, a type of cell found in the lining of the stomach. These cells contain several “switches” that help control when acid production is turned on or off. One switch is a protein called the h3 histamine receptor. When this protein is activated, parietal cells begin making more acid³.

Famotidine is a type of drug known as an h3 receptor antagonist (h3RA) or simply an h3 blocker. h3 blockers attach to the h3 histamine receptor, preventing it from turning on and blocking the parietal cells from creating extra acid³. Less acid in the stomach reduces the chances that acid reflux will occur.

Watch a video to see how h3 blockers like PEPCID^® work:

How To Take Over-The-Counter

Famotidine Tablets

In order to treat acid reflux symptoms like heartburn, adults and children 12 years or over can take a 20 mg tablet of famotidine once or twice per day. You can take famotidine tablets when you start to feel heartburn symptoms come on. Alternatively, to prevent heartburn, you can take one tablet 10 to 60 minutes before eating or drinking something that could trigger heartburn⁴.

Simply swallow the tablet with a full glass of water. Do not chew the tablet. For children under the age of 12, ask a doctor before using famotidine⁴.

Don’t use more than two famotidine tablets within a 24-hour period. Additionally, stop use and see a doctor if you need to take this product for more than two weeks².

If you have any questions about using famotidine tablets, ask your doctor or pharmacist.

When you need heartburn relief fast, try Maximum Strength PEPCID AC^® with 20 mg of famotidine. You can also take Maximum Strength PEPCID AC^® before a meal in order to help prevent symptoms from starting in the first place.

Maximum Strength PEPCID AC^® is not indicated to treat GERD. If you have been experiencing hearburn for three months, talk to your doctor before using Maxium Strength PEPCID AC^®. If you have trouble or pain swallowing food, vomiting with blood, or bloody or black stools, do not use Maximum Strength PEPCID AC^®, and see your doctor right away. These may be signs of a more serious condition.

Precautions & Side Effects

Famotidine side effects can include²:

Tell your doctor if you experience these side effects and they don’t go away. Additionally, call your doctor right away if you notice itching, swelling, hives or a rash, hoarseness, or breathing or swallowing problems².

Don’t use this medication if you have an allergy to famotidine or other acid-reducing drugs. Additionally, you should avoid taking famotidine at the same time as other heartburn medications unless your doctor recommends it. Tell your doctor about all prescription medications, over-the-counter drugs, and supplements that you are taking, since famotidine can sometimes interact with them.

References

• ¹How Does the Stomach Work? InformedHealth.org.
  Updated August 21, 2016. Accessed December 16, 2021.
• ²Famotidine. MedlinePlus. Revised October 15, 2017.
  Accessed December 16, 2021.
• ³Engevik AC, Kaji I, Goldenring JR. The Physiology of the
  Gastric Parietal Cell. Physiol Rev. 2020;100(2):573-602.
• ⁴Label: Pepcid AC Maximum Strength – Famotidine Tablet,
  Film Coated. DailyMed. Updated October 13, 2021. Accessed December 16, 2021.

Famotidine – StatPearls – NCBI Bookshelf

Kim Nguyen; Graham D. Dersnah; Rajni Ahlawat.

Author Information and Affiliations

Last Update: July 11, 2022.

Continuing Education Activity

Famotidine decreases the production of stomach acid, and its pharmacologic activity is used in the treatment of acid-related gastrointestinal conditions. Famotidine is available both by prescription and over-the-counter (OTC). It is FDA approved and available through prescription for the treatment of duodenal ulcer, gastric ulcer, and gastroesophageal reflux disease (GERD) in adults and children, with a further indication for treatment of pathological hypersecretory conditions in adults. Famotidine is also FDA approved for over-the-counter treatment and prevention of heartburn due to gastroesophageal reflux in adults and pediatrics. It also has off-label uses. This activity outlines the indications, mechanism of action, methods of administration, important adverse effects, contraindications, monitoring, and toxicity of famotidine, so providers can direct patient therapy as needed to achieve positive outcomes.

Objectives:

• Identify the mechanism of action of famotidine.

• Discuss the approved and off label indications for famotidine.

• Recall the contraindications and adverse event profile of famotidine.

• Explain interprofessional team strategies for improving care coordination and communication to advance famotidine therapy and improve outcomes.

Access free multiple choice questions on this topic.

Indications

Famotidine decreases the production of stomach acid, and its pharmacologic activity is used in the treatment of acid-related gastrointestinal conditions. [1][2] Famotidine is available both by prescription and over-the-counter (OTC). It is US Food and Drug Administration (FDA) approved and available through prescription for the treatment of duodenal ulcer, gastric ulcer, and gastroesophageal reflux disease (GERD) in adults and children, with a further indication for treatment of pathological hypersecretory conditions in adults.[3] Famotidine is also FDA approved for over-the-counter treatment and prevention of heartburn due to gastroesophageal reflux in adults and pediatrics.[4] Famotidine is used off-label for reducing gastrointestinal risks of NSAIDs.[5] It is also used off-label for the treatment of refractory urticarial, prevention of stress ulcer in critically-ill patients and symptomatic relief of gastritis.[6]

Mechanism of Action

Famotidine is a competitive histamine H-receptor antagonist (h3RA) that binds to the H-receptors located on the basolateral membrane of the parietal cell in the stomach, effectively blocking histamine actions. Its pharmacologic activity results in the inhibition of gastric secretion by suppressing acid concentration and volume of gastric secretion. Famotidine inhibits both basal and nocturnal gastric acid secretion as well as reduces gastric volume, acidity, and secretion stimulated by food, caffeine, insulin, and pentagastrin.[7][8][9]

Administration

Per famotidine’s package insert, it is available in intravenous (IV) solution, oral suspension, and tablet formulations (10 mg, 20 mg, and 40 mg). The intravenous solution can be administered as an IV push over at least two minutes and as an IV infusion over 15 to 30 minutes. Over-the-counter formulations are available in gel capsules, tablets, and chewable tablets of 10 mg or 20 mg. The oral tablet is administered without regard to meals. The suspension formulation should be shaken vigorously before use. The over-the-counter tablet should not be chewed, and the dose may be taken 10 to 60 minutes before consuming food or drinks known to cause heartburn. Patients should not take over-the-counter famotidine for more than 2 weeks unless directed by their health care provider. Famotidine is metabolized by the hepatic cytochrome P450 enzymes, but it has a minimal inhibitory impact on other drugs metabolism.[10] Per package insert, the following medications should not be used concurrently with famotidine: cefuroxime, dasatinib, delavirdine, neratinib, pazopanib, and risedronate.

Adverse Effects

The adverse effects of the intravenous formulation occur locally as it may irritate the injection site; however, the frequency has not been defined. Most common adverse effects include agitation (infants equal to 14%; adults less than 1%), headache (5%), dizziness (1%), diarrhea (2%), and constipation (1%). Due to central nervous system (CNS) adverse effects, longer dosing intervals or reduced doses may be used instead to adjust for the resulting longer elimination half-life of famotidine.[10][11][12] An increased risk of developing community-acquired pneumonia and acute gastroenteritis have been linked to the use of famotidine as well as other gastric acid inhibitors in the pediatric population. [13] Patients who use over-the-counter famotidine must notify their health care provider if they experience frequent chest pain, frequent wheezing particularly with heartburn, unexplained weight loss, stomach pain, heartburn more than 3 months, heartburn with lightheadedness, sweating, or dizziness. Over-the-counter famotidine must be discontinued if a patient’s heartburn continues and/or worsens, or if they use it for more than 14 days.[14]

Contraindications

Famotidine is contraindicated for use by patients with serious hypersensitivity to famotidine itself or any component of the formulation. Cross-sensitivity of h3RAs has been observed; therefore, famotidine should not be administered to patients with a history of hypersensitivity to cimetidine. In addition, the over-the-counter tablets should not be used if the patient has trouble and/or pain when swallowing food, vomiting with blood, or bloody or black stools. The over-the-counter tablets should also not be used by patients who are allergic to other acid reducers, have renal impairment, or are currently taking other acid reducers.

Monitoring

Famotidine is substantially excreted by the kidney; thus, it may be useful for healthcare professionals to monitor renal function especially in elderly patients. A patient’s complete blood count (CBC), gastric pH and occult blood in patients with gastrointestinal (GI) bleeding should be monitored.

Toxicity

As famotidine is excreted mainly by the kidney, the risk of toxic reactions may be greater in patients with impaired renal function. Dose adjustment in patients who have moderate to severe renal impairment is necessary.[11][12] Per famotidine’s package insert, oral doses outside of FDA-approved doses of up to 640 mg per day have been given to adult patients with pathological hypersecretory states with no serious adverse outcomes. Cases of overdose are similar to those encountered in normal clinical experience. Treatment of an overdose should include removing unabsorbed medications from the gastrointestinal tract, the patient should be monitored accordingly, and supportive therapy provided. Famotidine is classified as pregnancy category B and should be used during pregnancy only if needed. Famotidine is present in breast milk, and the decision for a mother to breastfeed during therapy should be based on the balance of risk to the infants and treatment benefits to the mother. Compared to other h3RAs, famotidine exhibit one of the lowest concentrations in break milk and is thus, maybe one of the preferred agents in this setting.[15][16]

Enhancing Healthcare Team Outcomes

The American Society of Health-System Pharmacists (ASHP) in 1999 released a guideline focusing on the prevention of stress ulcer in medical, surgical, respiratory, and pediatric intensive care unit (ICU) patients. Since then, and in recent years, the use of stress ulcer prophylaxis in a non-ICU setting, particularly in the general medical setting, have increased despite little to no evidence supporting its use. The use of acid-suppressive therapy (AST) is overused in hospital patients, with as many as 71% of patient’s receiving treatment without an appropriate indication in the general medicine ward. Furthermore, a significant number of patients continue on acid-suppressive therapy when discharged from the hospital which can lead to increased medical cost and the risk of adverse drug reactions for patients. Health care professionals play an important role in enhancing patient’s safety by minimizing the inappropriate use of AST. Physicians should carefully consider the need for AST in patients in the general medicine ward and pharmacist can communicate with physicians and ask about the unnecessary use of acid-suppressive therapy. Education about the proper use of acid-suppressive therapy in ICU settings per ASHP recommendations will help reduce its inappropriate use significantly.[17][18][19]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

References

1.

McCullough AJ, Graham DY, Knuff TE, Lanza FL, Levenson HL, Lyon DT, Munsell WP, Perozza J, Roufail WM, Sinar DR. Suppression of nocturnal acid secretion with famotidine accelerates gastric ulcer healing. Gastroenterology. 1989 Oct;97(4):860-6. [PubMed: 2570730]

2.

Vinayek R, Howard JM, Maton PN, Wank SA, Slaff JI, Gardner JD, Jensen RT. Famotidine in the therapy of gastric hypersecretory states. Am J Med. 1986 Oct 24;81(4B):49-59. [PubMed: 2877575]

3.

Keithley JK. Histamine h3-receptor antagonists. Nurs Clin North Am. 1991 Jun;26(2):361-73. [PubMed: 1675461]

4.

Nonprescription version of famotidine wins FDA approval. Am J Health Syst Pharm. 1995 Jul 01;52(13):1377. [PubMed: 7671034]

5.

Hudson N, Taha AS, Russell RI, Trye P, Cottrell J, Mann SG, Swanell AJ, Sturrock RD, Hawkey CJ. Famotidine for healing and maintenance in nonsteroidal anti-inflammatory drug-associated gastroduodenal ulceration. Gastroenterology. 1997 Jun;112(6):1817-22. [PubMed: 9178671]

6.

Inalöz SS, Goral V, Sari I, Canberk Y, Ulak G. Omeprazole, nitrendipine, famotidine and stress-induced ulcers. Acta Gastroenterol Belg. 1997 Jul-Sep;60(3):192-6. [PubMed: 9396173]

7.

Talke PO, Solanki DR. Dose-response study of oral famotidine for reduction of gastric acidity and volume in outpatients and inpatients. Anesth Analg. 1993 Dec;77(6):1143-8. [PubMed: 8250305]

8.

Berlin RG, Clineschmidt BV, Majka JA. Famotidine: an appraisal of its mode of action and safety. Am J Med. 1986 Oct 24;81(4B):8-12. [PubMed: 2877577]

9.

Miyata K, Kamato T, Nishida A, Honda K. Studies on the mechanism for the gastric mucosal protection by famotidine in rats. Jpn J Pharmacol. 1991 Feb;55(2):211-22. [PubMed: 2067140]

10.

Poluzzi E, Raschi E, Moretti U, De Ponti F. Drug-induced torsades de pointes: data mining of the public version of the FDA Adverse Event Reporting System (AERS). Pharmacoepidemiol Drug Saf. 2009 Jun;18(6):512-8. [PubMed: 19358226]

11.

Echizen H, Ishizaki T. Clinical pharmacokinetics of famotidine. Clin Pharmacokinet. 1991 Sep;21(3):178-94. [PubMed: 1764869]

12.

Lin JH, Chremos AN, Yeh KC, Antonello J, Hessey GA. Effects of age and chronic renal failure on the urinary excretion kinetics of famotidine in man. Eur J Clin Pharmacol. 1988;34(1):41-6. [PubMed: 2896129]

13.

Canani RB, Cirillo P, Roggero P, Romano C, Malamisura B, Terrin G, Passariello A, Manguso F, Morelli L, Guarino A., Working Group on Intestinal Infections of the Italian Society of Pediatric Gastroenterology, Hepatology and Nutrition (SIGENP). Therapy with gastric acidity inhibitors increases the risk of acute gastroenteritis and community-acquired pneumonia in children. Pediatrics. 2006 May;117(5):e817-20. [PubMed: 16651285]

14.

McRorie JW, Kirby JA, Miner PB. Histamine2-receptor antagonists: Rapid development of tachyphylaxis with repeat dosing. World J Gastrointest Pharmacol Ther. 2014 May 06;5(2):57-62. [PMC free article: PMC4023325] [PubMed: 24868486]

15.

Richter JE. Review article: the management of heartburn in pregnancy. Aliment Pharmacol Ther. 2005 Nov 01;22(9):749-57. [PubMed: 16225482]

16.

Garbis H, Elefant E, Diav-Citrin O, Mastroiacovo P, Schaefer C, Vial T, Clementi M, Valti E, McElhatton P, Smorlesi C, Rodriguez EP, Robert-Gnansia E, Merlob P, Peiker G, Pexieder T, Schueler L, Ritvanen A, Mathieu-Nolf M. Pregnancy outcome after exposure to ranitidine and other h3-blockers. A collaborative study of the European Network of Teratology Information Services. Reprod Toxicol. 2005 Mar-Apr;19(4):453-8. [PubMed: 15749258]

17.

Grube RR, May DB. Stress ulcer prophylaxis in hospitalized patients not in intensive care units. Am J Health Syst Pharm. 2007 Jul 01;64(13):1396-400. [PubMed: 17592004]

18.

Farrell CP, Mercogliano G, Kuntz CL. Overuse of stress ulcer prophylaxis in the critical care setting and beyond.