Ranitidine: Uses, Side Effects, and Safety Information
Ranitidine is a histamine H2-blocker that reduces stomach acid. It was used to treat acid reflux, gastroesophageal reflux disease (GERD), peptic ulcers, and certain other stomach-acid conditions. In many countries, ranitidine is no longer available because of concerns about a contaminant called N-nitrosodimethylamine (NDMA).
Ranitidine can reduce stomach acid, but it has been withdrawn from sale in many countries because of possible NDMA contamination. Do not start leftover or online ranitidine without advice from a doctor or pharmacist.
Key facts at a glance
- ATC
- A02BA02
- Generic
- Ranitidine
- Class
- h2-blocker
- Brands
- Zantac
- Availability
- behind_counter
- Pregnancy
- B
- Lactation
- caution
- Half-life (h)
- 2.5
- Onset (min)
- 60
- Duration (h)
- 12
- Routes
- oral
- Forms
- tablet
- Regions
- CN, US, EU, 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
8 groupspregnancy
first trimesterno specific adjustment
use only if clearly needed, benefits must outweigh potential risks
standard prenatal care
Use with caution and monitor for adverse effects.
pregnancy
second trimesterno specific adjustment
continue if already taking for therapeutic need
standard prenatal care
Use with caution and monitor for adverse effects.
pregnancy
third trimesterno specific adjustment
use lowest effective dose
standard prenatal care
Use with caution and monitor for adverse effects.
lactation
breastfeedingno adjustment needed
compatible with breastfeeding, infant exposure minimal
no specific monitoring required
geriatric
elderlyno dose adjustment for age alone
use with caution due to increased risk of side effects, monitor renal function
periodic renal function assessment
Use with caution and monitor for adverse effects.
pediatric_age
infants and childrenweight-based dosing required
use approved pediatric formulation, do not exceed recommended doses
monitor growth parameters with long-term use
Use with caution and monitor for adverse effects.
renal_impairment
severe renal impairmentreduce dose by 50%
adjust dose in patients with CrCl less than 50 mL/min
monitor renal function periodically
Use with caution and monitor for adverse effects.
hepatic_impairment
severe hepatic impairmentno significant dose adjustment required
use with caution in severe hepatic impairment
monitor for altered drug metabolism
Use with caution and monitor for adverse effects.
Statistics and clinical data
Commonly prescribed since
General prescribing information
Drug class
Drug class information
Common uses
Common therapeutic uses
Market status
Safety and regulatory information
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 22, 2026. · Read our editorial policy