Famotidine
Famotidine is an H2 receptor antagonist that reduces stomach acid production by blocking histamine signals, treating peptic ulcers, GERD, and other related conditions.
Famotidine is an acid-reducing medication that treats ulcers, GERD, and heartburn by blocking H2 receptors to decrease stomach acid production.
Key facts at a glance
- ATC
- A02BA03
- RxNorm
- 4278
- Generic
- Famotidine
- Class
- atc-a02
- Brands
- Calmicid, Duexis, Duo Fusion, Pepcid, Zantac Reformulated Aug 2022, Pepcid Complete, Tums Dual Action
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- injection, tablet, solution, suspension
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
7 groupspregnancy
all trimestersno adjustment needed
use only if clearly needed and benefits outweigh risks
standard prenatal care
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
use with caution; small amounts excreted in breast milk
monitor infant for gastrointestinal disturbances
Use with caution and monitor for adverse effects.
geriatric
elderlyreduce dose in renal impairment
use standard dosing; assess renal function before initiating
monitor renal function periodically
pediatric_age
children 1 month to 16 yearsweight-based dosing required
approved for pediatric use; follow weight-based dosing guidelines
monitor for adverse effects
renal_impairment
mild to moderatereduce dose by 50%
adjust dose based on creatinine clearance; avoid in severe renal impairment if possible
monitor renal function regularly
Use with caution and monitor for adverse effects.
renal_impairment
severereduce dose by 75% or avoid
use with extreme caution; consider alternative therapy
frequent monitoring of renal function and drug levels
Use with caution and monitor for adverse effects.
hepatic_impairment
mild to moderateno adjustment needed
no major dose adjustment required; use standard dosing
standard monitoring
Statistics and clinical data
Drug class
Famotidine belongs to the H2 receptor antagonist class of drugs
FDA approval year
FDA approved Famotidine for medical use
Common therapeutic uses
Primary indications for Famotidine prescription
Mechanism of action
How Famotidine works to reduce stomach acid
Famotidine is used to treat and prevent peptic ulcers (both gastric and duodenal), gastroesophageal reflux disease (GERD), heartburn, and conditions associated with excessive stomach acid secretion.
Famotidine works as a competitive antagonist at histamine H2 receptors on gastric parietal cells, preventing histamine from stimulating acid production and thereby reducing both the volume and concentration of gastric secretions.
Famotidine may affect the absorption of certain medications that require stomach acid for optimal absorption. It is available both by prescription and over-the-counter. Patients should follow dosage instructions carefully and consult a healthcare provider if symptoms persist.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy