Famotidine 20mg 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
Antiulcer agent
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 medicine that reduces the amount of acid your stomach makes. It's used to treat and prevent heartburn, ulcers, and other conditions where too much stomach acid causes problems.
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 help prevent heartburn, take the medication before consuming foods or drinks that trigger heartburn. Follow the dosage instructions provided by your doctor or as indicated on the packaging.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of 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 your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take 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 help prevent heartburn, take the medication before consuming foods or drinks that trigger heartburn. Follow the dosage instructions provided by your doctor or as indicated on the packaging.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry location, avoiding the bathroom. Keep all medications in a secure place, out of 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 your medication, consult your pharmacist. You may also want to check if there are drug take-back programs available 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take 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, chocolate, peppermint).
- Eat smaller, more frequent meals.
- Avoid eating close to bedtime (within 2-3 hours).
- Elevate the head of your bed if you experience nighttime reflux.
- Maintain a healthy weight.
- Quit 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 GERD: 20 mg twice daily. For heartburn (OTC): 10-20 mg as needed, up to twice daily.
Dose Range:
10 - 40 mg
Condition-Specific Dosing:
active_duodenal_ulcer:
40 mg once daily at bedtime or 20 mg twice daily for 4-8 weeks.
gastric_ulcer:
40 mg once daily at bedtime for 6-8 weeks.
gerd:
20 mg twice daily for up to 6 weeks. For erosive esophagitis: 20-40 mg twice daily for up to 12 weeks.
pathological_hypersecretory_conditions_zollinger_ellison_syndrome:
Initial: 20 mg every 6 hours; may increase up to 160 mg every 6 hours.
heartburn_prevention_otc:
10 mg 1 hour before eating, up to twice daily.
heartburn_relief_otc:
10-20 mg as needed, up to twice daily.
Pediatric Dosing
Neonatal:
Not established
Infant:
GERD (1-3 months): 0.5 mg/kg once daily. GERD (3 months-1 year): 0.5 mg/kg twice daily. Max 20 mg/day.
Child:
GERD (1-16 years): 0.5 mg/kg twice daily. Max 40 mg twice daily. Peptic Ulcer Disease (1-16 years): 0.5 mg/kg once daily at bedtime or 0.25 mg/kg twice daily. Max 40 mg/day.
Adolescent:
Same as adult dosing for GERD and PUD.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment typically 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 is necessary. For example, 20 mg once daily or 20 mg every other day.
Hepatic Impairment:
Mild:
No adjustment
Moderate:
No adjustment
Severe:
No adjustment (primarily renally eliminated)
Pharmacology
Mechanism of Action
Famotidine is a competitive inhibitor of histamine H2-receptors. It reversibly binds to H2-receptors on the gastric parietal cells, leading to a reduction in both basal and stimulated gastric acid secretion. This reduces the volume of gastric acid and the concentration of hydrogen ions.
Pharmacokinetics
Absorption:
Bioavailability:
40-45%
Tmax:
1-3 hours
FoodEffect:
Food may slightly increase absorption but does not significantly affect clinical efficacy.
Distribution:
Vd:
1.3 L/kg
ProteinBinding:
15-20%
CnssPenetration:
Limited (can cross blood-brain barrier, but typically low concentrations)
Elimination:
HalfLife:
2.5-3.5 hours (prolonged in renal impairment)
Clearance:
Not available
ExcretionRoute:
Renal (65-70% of absorbed dose)
Unchanged:
65-70% (of absorbed dose)
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 or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ 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 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 persist, contact your doctor for guidance:
Headache
Reporting Side Effects
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 for advice. 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 or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ 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 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 persist, contact your doctor for guidance:
Headache
Reporting Side Effects
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 for advice. 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 allergic reaction (rash, itching/swelling, severe dizziness, trouble breathing)
- Unusual tiredness or weakness
- Easy bruising or bleeding
- Signs of liver problems (e.g., dark urine, yellowing eyes/skin, persistent nausea/vomiting, severe stomach/abdominal pain)
- Confusion or hallucinations (especially in elderly or those with kidney problems)
- Chest pain, shortness of breath, or pain spreading to arm/shoulder (may indicate a heart attack, not just heartburn)
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. Describe the allergic reaction and its symptoms.
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
A history of heartburn lasting 3 months or more
Current use of specific medications, such as:
+ Cefditoren
+ Dasatinib
+ Delavirdine
+ Fosamprenavir
Please note that this is not an exhaustive list of 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. Do not initiate, discontinue, or modify the dosage of any medication without consulting 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. Describe the allergic reaction and its symptoms.
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
A history of heartburn lasting 3 months or more
Current use of specific medications, such as:
+ Cefditoren
+ Dasatinib
+ Delavirdine
+ Fosamprenavir
Please note that this is not an exhaustive list of 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. Do not initiate, discontinue, or modify the dosage of any medication without consulting your doctor.
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 existing kidney problems or are 65 years or older, consult your doctor, as you may be at a higher risk of experiencing certain side effects. These potential side effects include hallucinations (perceiving things that are not present), seizures, and feelings of agitation, confusion, sluggishness, or being out of sorts, which have been reported in individuals with kidney issues and older adults.
This medication may interfere with the absorption of other oral medications, 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 potential interactions.
If you are pregnant, planning to become pregnant, or are breast-feeding, it is crucial to discuss your situation with your doctor. You and your doctor will need to weigh the benefits and risks of this medication to both you and your baby to make an informed decision.
This medication may interfere with the absorption of other oral medications, 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 potential interactions.
If you are pregnant, planning to become pregnant, or are breast-feeding, it is crucial to discuss your situation with your doctor. You and your doctor will need to weigh the benefits and risks of this medication to both you and your baby to make an informed decision.
Overdose Information
Overdose Symptoms:
- Restlessness
- Tachycardia (fast heart rate)
- Hypotension (low blood pressure)
- Prostration (extreme weakness)
- Tachypnea (rapid breathing)
- Salivation
- Vomiting
- Diarrhea
- Tremors
- Convulsions
What to Do:
Call 911 or Poison Control (1-800-222-1222) immediately. Treatment is symptomatic and supportive. Gastric lavage may be considered.
Drug Interactions
Major Interactions
- Cefditoren (reduced absorption)
- Cefpodoxime (reduced absorption)
- Dasatinib (reduced absorption)
- Delavirdine (reduced absorption)
- Erlotinib (reduced absorption)
- Fosamprenavir (reduced absorption)
- Iron salts (reduced absorption)
- Itraconazole (reduced absorption)
- Ketoconazole (reduced absorption)
- Ledipasvir/Sofosbuvir (reduced absorption)
- Mesalamine (reduced absorption)
- Mycophenolate mofetil (reduced absorption)
- Nilotinib (reduced absorption)
- Posaconazole (reduced absorption)
- Rilpivirine (reduced absorption)
- Sunitinib (reduced absorption)
- Velpatasvir/Sofosbuvir (reduced absorption)
Moderate Interactions
- Atazanavir (reduced absorption)
- Dabigatran (increased exposure)
- Digoxin (increased absorption)
- Fluconazole (reduced absorption)
- Indinavir (reduced absorption)
- Levoketoconazole (reduced absorption)
- Nelfinavir (reduced absorption)
- Phenytoin (increased absorption)
- Ticagrelor (reduced absorption)
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: Famotidine is primarily renally eliminated; dose adjustment is required in renal impairment.
Timing: Prior to initiation in patients with known or suspected renal impairment.
Routine Monitoring
Symptom resolution (e.g., heartburn, dyspepsia)
Frequency: Daily/as needed
Target: Reduction or elimination of symptoms
Action Threshold: Lack of symptom improvement or worsening symptoms after appropriate duration of therapy may indicate need for further evaluation or alternative treatment.
Renal function (CrCl)
Frequency: Periodically (e.g., every 3-6 months) for long-term use or in patients with fluctuating renal function.
Target: Stable CrCl
Action Threshold: Significant decline in CrCl may necessitate dose adjustment.
Symptom Monitoring
- Resolution of heartburn
- Reduction in acid reflux episodes
- Decrease in abdominal pain or discomfort
- Improvement in swallowing difficulties (if related to GERD)
- Signs of gastrointestinal bleeding (e.g., black, tarry stools; coffee-ground vomit) if treating ulcers
Special Patient Groups
Pregnancy
Famotidine is generally considered safe for use during pregnancy. Animal studies have not shown harm to the fetus, and human data suggest low risk. Use only if clearly needed.
Trimester-Specific Risks:
First Trimester:
Low risk, Category B.
Second Trimester:
Low risk, Category B.
Third Trimester:
Low risk, Category B.
Lactation
Famotidine is excreted into breast milk in small amounts. It is generally considered compatible with breastfeeding, but caution is advised, especially with higher doses or in premature infants. Monitor infant for potential adverse effects (e.g., changes in feeding, drowsiness).
Infant Risk:
Low risk (L2)
Pediatric Use
Dosing is established for children and adolescents for various indications, but generally not recommended for infants under 1 month. Dose adjustments are necessary based on weight and age. Close monitoring for CNS effects is important, especially in younger children.
Geriatric Use
Elderly patients may be more susceptible to adverse effects, particularly CNS effects (e.g., confusion, dizziness), due to age-related decline in renal function. Dose adjustment is often necessary based on creatinine clearance. Start with lower doses and monitor closely.
Clinical Information
Clinical Pearls
- Famotidine is best taken 30-60 minutes before meals if used for heartburn prevention.
- For active ulcers, it's often taken once daily at bedtime to suppress nocturnal acid secretion.
- Do not take antacids within 1-2 hours of famotidine as antacids can reduce its absorption.
- Patients should be advised not to exceed the recommended dose or duration of OTC use without consulting a healthcare professional.
- Long-term use of acid suppressants, including H2RAs, may be associated with an increased risk of C. difficile infection and bone fractures, though the risk with H2RAs is generally lower than with PPIs.
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)
- Antacids (e.g., Calcium carbonate, Aluminum hydroxide/Magnesium hydroxide)
- Sucralfate (for ulcer treatment)
Cost & Coverage
Average Cost:
$10 - $30 per 30 tablets (20mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Preferred Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's 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 be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to 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 seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.