Famotidine 40mg Tablets
It is used to treat or prevent GI (gastrointestinal) ulcers.It is used to treat gastroesophageal reflux disease (GERD; acid reflux). It is used to treat heartburn and sour stomach.It is used to treat syndromes caused by lots of stomach acid.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Histamine H2-receptor antagonist
Pharmacologic Class
Histamine H2-receptor antagonist
Pregnancy Category
Category B
FDA Approved
Oct 1986
DEA Schedule
Not Controlled
Overview
What is this medicine?
Famotidine is a medication that reduces the amount of acid produced in your stomach. It's used to treat and prevent heartburn, indigestion, and ulcers in the stomach and intestines.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. However, before taking antacids with this medication, consult your doctor. It's essential to swallow the medication whole and not chew it.
To prevent heartburn, take the medication before consuming foods or drinks that trigger heartburn. Adhere to the dosage schedule recommended by your doctor or as indicated on the packaging.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to inquire about drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosage schedule. Avoid taking two doses at the same time or taking extra doses. Since this medication is often taken as needed, do not take it more frequently than recommended by your doctor.
To use this medication correctly, follow your doctor's instructions and read all the information provided. You can take this medication with or without food. However, before taking antacids with this medication, consult your doctor. It's essential to swallow the medication whole and not chew it.
To prevent heartburn, take the medication before consuming foods or drinks that trigger heartburn. Adhere to the dosage schedule recommended by your doctor or as indicated on the packaging.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also want to inquire about drug take-back programs in your area.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosage schedule. Avoid taking two doses at the same time or taking extra doses. Since this medication is often taken as needed, do not take it more frequently than recommended by your doctor.
Lifestyle & Tips
- Avoid foods and drinks that trigger heartburn (e.g., spicy foods, fatty foods, caffeine, alcohol, citrus, chocolate).
- Eat smaller, more frequent meals.
- Avoid eating close to bedtime (within 2-3 hours).
- Elevate the head of your bed if you experience nighttime heartburn.
- Maintain a healthy weight.
- Avoid smoking.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
For active duodenal ulcer: 40 mg once daily at bedtime or 20 mg twice daily. For active gastric ulcer: 40 mg once daily at bedtime. For GERD: 20 mg twice daily. For pathological hypersecretory conditions (e.g., Zollinger-Ellison Syndrome): 20 mg every 6 hours, may be increased up to 160 mg every 6 hours.
Dose Range:
20 - 640 mg
Condition-Specific Dosing:
Duodenal Ulcer (acute):
40 mg once daily at bedtime or 20 mg twice daily for 4-8 weeks.
Gastric Ulcer (acute):
40 mg once daily at bedtime for 6-8 weeks.
GERD:
20 mg twice daily for up to 6-12 weeks.
Erosive Esophagitis:
20 mg or 40 mg twice daily for up to 12 weeks.
Pathological Hypersecretory Conditions (Zollinger-Ellison Syndrome):
Initial: 20 mg every 6 hours; may be increased to 160 mg every 6 hours.
Pediatric Dosing
Neonatal:
Not established (limited data, generally avoided).
Infant:
Not established (limited data, generally avoided).
Child:
GERD: 0.5 mg/kg/day divided twice daily (max 40 mg/day). Peptic Ulcer: 0.5 mg/kg/day divided twice daily (max 40 mg/day).
Adolescent:
Similar to adult dosing for GERD/PUD: 20 mg twice daily or 40 mg once daily.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed (CrCl >50 mL/min).
Moderate:
Reduce dose by 50% or extend dosing interval to every 36-48 hours (CrCl 10-50 mL/min).
Severe:
Reduce dose by 50% or extend dosing interval to every 36-48 hours (CrCl <10 mL/min).
Dialysis:
Administer after dialysis. Dose reduction or extended interval (e.g., 20 mg every 48 hours or 20 mg once daily for 3 days then 20 mg every other day).
Hepatic Impairment:
Mild:
No specific adjustment.
Moderate:
No specific adjustment.
Severe:
No specific adjustment, but caution advised due to potential for CNS effects in severe liver disease.
Pharmacology
Mechanism of Action
Famotidine is a competitive inhibitor of histamine H2-receptors located on the gastric parietal cells. By blocking histamine's action, it inhibits both basal and stimulated gastric acid secretion, reducing both the volume and acid content of gastric secretions.
Pharmacokinetics
Absorption:
Bioavailability:
40-45%
Tmax:
1-3 hours
FoodEffect:
Food may slightly increase bioavailability and delay Tmax, but not clinically significant.
Distribution:
Vd:
0.96-1.3 L/kg
ProteinBinding:
15-20%
CnssPenetration:
Limited (can cross blood-brain barrier, but typically low concentrations; higher in renal impairment)
Elimination:
HalfLife:
2.5-3.5 hours (prolonged in renal impairment to 11-13 hours)
Clearance:
Not available
ExcretionRoute:
Renal (65-70% unchanged drug)
Unchanged:
65-70%
Pharmacodynamics
OnsetOfAction:
Within 1 hour
PeakEffect:
1-3 hours
DurationOfAction:
10-12 hours (single dose)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction, including:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Dizziness or fainting
Fast or abnormal heartbeat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor for advice:
Headache
Important Note
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, don't hesitate to reach out to your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor immediately or seek emergency medical attention:
Signs of an allergic reaction, including:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Dizziness or fainting
Fast or abnormal heartbeat
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although many people may not experience any side effects or only have mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor for advice:
Headache
Important Note
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, don't hesitate to reach out to your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe stomach pain
- Black, tarry stools or vomit that looks like coffee grounds (signs of bleeding)
- Difficulty or pain when swallowing
- Chest pain (especially with shortness of breath, sweating, or pain spreading to arms/neck/jaw - could be heart attack)
- Unexplained weight loss
- Rash, hives, swelling of face/lips/tongue/throat, difficulty breathing (signs of allergic reaction)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health issues, including:
+ Black or bloody stools
+ Heartburn accompanied by lightheadedness, sweating, dizziness, or wheezing
+ Chest pain
+ Shoulder pain with shortness of breath
+ Pain that radiates to the arms, neck, or shoulders
+ Lightheadedness
+ Excessive sweating
+ Vomiting blood
+ Difficulty or pain when swallowing food
If you have experienced heartburn for 3 months or more
If you are currently taking any of the following medications: cefditoren, dasatinib, delavirdine, or fosamprenavir
Please note that this is not an exhaustive list of all potential interactions. It is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist to ensure safe use. Never start, stop, or adjust the dosage of any medication without consulting your doctor first.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health issues, including:
+ Black or bloody stools
+ Heartburn accompanied by lightheadedness, sweating, dizziness, or wheezing
+ Chest pain
+ Shoulder pain with shortness of breath
+ Pain that radiates to the arms, neck, or shoulders
+ Lightheadedness
+ Excessive sweating
+ Vomiting blood
+ Difficulty or pain when swallowing food
If you have experienced heartburn for 3 months or more
If you are currently taking any of the following medications: cefditoren, dasatinib, delavirdine, or fosamprenavir
Please note that this is not an exhaustive list of all potential interactions. It is crucial to discuss all your medications (prescription, over-the-counter, natural products, and vitamins) and health problems with your doctor and pharmacist to ensure safe use. Never start, stop, or adjust the dosage of any medication without consulting your doctor first.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to your doctor's prescribed treatment duration and do not exceed it. If you have pre-existing kidney problems or are 65 years or older, consult your doctor, as you may be at a higher risk of experiencing adverse effects. These effects can include hallucinations (perceiving things that are not present), seizures, and feelings of agitation, confusion, sluggishness, or being out of sorts.
This medication may interfere with the absorption of other oral medications, potentially reducing their effectiveness. If you are taking other medications by mouth, your doctor may advise you to take them at a different time than this medication to minimize interactions.
Before starting this medication, inform your doctor if you are pregnant, planning to become pregnant, or are breast-feeding. Your doctor will discuss the potential benefits and risks of this medication to both you and your baby, allowing you to make an informed decision.
This medication may interfere with the absorption of other oral medications, potentially reducing their effectiveness. If you are taking other medications by mouth, your doctor may advise you to take them at a different time than this medication to minimize interactions.
Before starting this medication, inform your doctor if you are pregnant, planning to become pregnant, or are breast-feeding. Your doctor will discuss the potential benefits and risks of this medication to both you and your baby, allowing you to make an informed decision.
Overdose Information
Overdose Symptoms:
- Restlessness
- Tachycardia (fast heart rate)
- Hypotension (low blood pressure)
- Flushing
- Dry mouth
What to Do:
Seek immediate medical attention or call a poison control center (1-800-222-1222). Treatment is generally symptomatic and supportive.
Drug Interactions
Major Interactions
- Cefditoren (reduced absorption)
- Cefpodoxime (reduced absorption)
- Dasatinib (reduced absorption)
- Delavirdine (reduced absorption)
- Erlotinib (reduced absorption)
- Fosamprenavir (reduced absorption)
- Indinavir (reduced absorption)
- Itraconazole (reduced absorption)
- Ketoconazole (reduced absorption)
- Ledipasvir/Sofosbuvir (reduced absorption)
- Levoketoconazole (reduced absorption)
- Mesalamine (reduced absorption)
- Mycophenolate mofetil (reduced absorption)
- Neratinib (reduced absorption)
- Nilotinib (reduced absorption)
- Posaconazole (reduced absorption)
- Rilpivirine (reduced absorption)
- Sotorasib (reduced absorption)
- Velpatasvir/Sofosbuvir (reduced absorption)
Moderate Interactions
- Atazanavir (reduced absorption)
- Dabigatran (increased absorption)
- Iron salts (reduced absorption)
- Lumacaftor/Ivacaftor (reduced absorption)
- Octreotide (reduced absorption)
- Phenytoin (potential for altered absorption)
- Theophylline (potential for altered absorption)
Minor Interactions
- Antacids (administer 1-2 hours apart)
Monitoring
Routine Monitoring
Symptom resolution (e.g., heartburn, dyspepsia)
Frequency: Daily/Weekly
Target: Reduction or absence of symptoms
Action Threshold: Persistent or worsening symptoms may require dose adjustment or alternative therapy.
Renal function (CrCl)
Frequency: Periodically, especially in elderly or those with pre-existing renal impairment
Target: Not applicable
Action Threshold: If CrCl falls below 50 mL/min, consider dose reduction.
Symptom Monitoring
- Heartburn
- Acid indigestion
- Dyspepsia
- Abdominal pain
- Difficulty swallowing
- Black, tarry stools (sign of GI bleeding)
- Unusual fatigue or weakness
Special Patient Groups
Pregnancy
Famotidine is generally considered safe for use during pregnancy (Pregnancy Category B). Studies in animals have not shown harm to the fetus, and there are no adequate and well-controlled studies in pregnant women, but human experience suggests low risk.
Trimester-Specific Risks:
First Trimester:
Low risk, often used for severe heartburn.
Second Trimester:
Low risk.
Third Trimester:
Low risk.
Lactation
Famotidine is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding (Lactation Risk L2 - Safer). Monitor infant for potential side effects like drowsiness or GI upset, though unlikely.
Infant Risk:
Low risk. Levels in milk are low and infant exposure is minimal. No adverse effects reported in breastfed infants.
Pediatric Use
Famotidine is used in pediatric patients for GERD and peptic ulcer disease, but dosing must be carefully calculated based on weight and age. Use in neonates and infants is generally off-label and requires specialist consultation.
Geriatric Use
No specific dose adjustment is needed based solely on age, but renal function should be assessed, as elderly patients are more likely to have impaired renal function, which necessitates dose reduction. Elderly patients may also be more susceptible to CNS side effects (e.g., confusion) if renal impairment is present.
Clinical Information
Clinical Pearls
- Famotidine is generally well-tolerated. Headache, dizziness, and constipation/diarrhea are common side effects.
- For occasional heartburn, lower doses (e.g., 10-20 mg) are available over-the-counter.
- Take famotidine with or without food.
- For optimal effect, take 30-60 minutes before a meal that might trigger heartburn.
- Do not take famotidine at the same time as antacids; separate by at least 1-2 hours.
- Long-term use of H2RAs is generally safe, but for chronic conditions, PPIs might be preferred or considered.
- Patients with renal impairment are at higher risk for CNS side effects (e.g., confusion, delirium) due to reduced clearance.
Alternative Therapies
- Other H2-receptor antagonists (e.g., Ranitidine [though largely withdrawn], Cimetidine, Nizatidine)
- Proton pump inhibitors (PPIs) (e.g., Omeprazole, Esomeprazole, Lansoprazole, Pantoprazole, Rabeprazole) - generally more potent for acid suppression.
- Antacids (e.g., Calcium carbonate, Aluminum hydroxide/Magnesium hydroxide) - for immediate, short-term relief.
- Sucralfate (for ulcer treatment, forms a protective barrier).
Cost & Coverage
Average Cost:
Varies, typically $10-$30 per 30 tablets
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist. If you have any questions or concerns about this medication, don't hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.