About naltrexone
Opioid antagonist
Used for
- Prevents relapse to opioid dependence after detoxification
- Treats alcohol dependence alongside counseling and support
Usual adult dose
380 mg intramuscularly every 4 weeks, administered by a healthcare professional.
Common side effects
- Injection-site pain or reactions
- Nausea, vomiting, or diarrhea
- Headache, dizziness, or tiredness
- Liver enzyme changes
Important warnings
- Must be opioid-free before starting; otherwise, sudden severe withdrawal can occur.
- Blocks opioid pain medicines and may reduce their effects.
- Opioid overdose risk increases after treatment stops or doses are missed.
- Seek urgent care for severe injection-site reactions or possible liver injury.
Pregnancy
Use only when the expected benefit outweighs potential risk; pregnancy data are limited.
Breastfeeding
Information is limited; discuss risks and benefits with a healthcare professional.
Interactions
- Opioid pain medicines, cough medicines, or antidiarrheals may be blocked.
- Buprenorphine or methadone can trigger withdrawal or have reduced effects.
- Tell clinicians before surgery or emergency pain treatment.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.