Naltrexone
Naltrexone is an opioid antagonist medication used to treat both opioid and alcohol dependence. It works by blocking the effects of opioids and reducing alcohol cravings, helping patients maintain abstinence from these substances.
An opioid antagonist used to treat opioid and alcohol dependence by blocking the effects of these substances and reducing cravings.
Key facts at a glance
- ATC
- N07BB04
- RxNorm
- 7243
- Generic
- Naltrexone
- Class
- atc-n07
- Brands
- ReVia, Contrave, Vivitrol
- Availability
- rx
- Pregnancy
- C
- Lactation
- caution
- Routes
- oral
- Forms
- tablet, capsule, injection
- 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
- 50mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 25mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 25mg once daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
9 groupspregnancy
first trimesteravoid if possible
avoid use during pregnancy unless benefits outweigh risks
regular fetal monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
pregnancy
second third trimesteravoid if possible
discontinue naltrexone before conception if possible
fetal growth monitoring
Use of this medication in this population requires careful consideration of risks and benefits.
lactation
breastfeedingnot recommended
avoid naltrexone while breastfeeding due to potential excretion in breast milk
observe infant for unusual symptoms
geriatric
elderlystart at lower dose
use reduced starting dose and titrate slowly; monitor renal and hepatic function
regular monitoring of liver function and renal function
Use with caution and monitor for adverse effects.
pediatric_age
children adolescentsnot recommended
not approved for use in patients under 18 years of age
n/a
Use of this medication in this population requires careful consideration of risks and benefits.
renal_impairment
mild moderateno adjustment required
no dose adjustment needed for mild to moderate renal impairment
periodic renal function monitoring
renal_impairment
severeuse with caution
use with caution in severe renal impairment; consider dose reduction
close monitoring of renal function
Use with caution and monitor for adverse effects.
hepatic_impairment
mild moderateuse with caution
use with caution; monitor liver function tests
regular liver function test monitoring
Use with caution and monitor for adverse effects.
hepatic_impairment
severeavoid
avoid in acute hepatitis or severe hepatic impairment including cirrhosis
liver function monitoring if used
Use of this medication in this population requires careful consideration of risks and benefits.
Statistics and clinical data
FDA approval year
Original FDA approval for opioid dependence; alcohol dependence approval in 1994
Drug class
ATC code: N07BC01
Mechanism of action
Competitively binds to opioid receptors, blocking effects of endogenous opioids
Common uses
FDA-approved indications: alcohol dependence and opioid dependence treatment
Naltrexone is primarily used to treat opioid use disorder (to prevent relapse) and alcohol use disorder (to reduce alcohol cravings and consumption). It may also be used off-label for conditions like pathological gambling, kleptomania, and low-dose naltrexone is sometimes prescribed for autoimmune conditions.
Naltrexone is a competitive antagonist at opioid receptors, particularly mu-opioid receptors. By blocking these receptors, it prevents the euphoric and analgesic effects of opioids and reduces the rewarding effects of alcohol, helping to diminish cravings and support abstinence.
Patients must be opioid-free for 7-10 days before starting to avoid precipitated withdrawal. It does not block the effects of alcohol itself (unlike disulfiram) and does not prevent overdose from alcohol alone. Common side effects include nausea, headache, and dizziness. Patients should carry emergency identification as they may not respond to opioid pain medications in emergencies. Requires regular monitoring of liver function.
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 August 24, 2026. · Read our editorial policy