Naltrexone: Uses, Safety and Drug Interactions

Naltrexone: uses, safety and drug interactions

Overview: Naltrexone is an opioid-receptor antagonist. The reference for this page is an oral tablet, not a long-acting injection. Its purpose and safety precautions are different from those of opioid medicines that relieve pain. It does not produce the alcohol-triggered aversive reaction associated with disulfiram.

Uses and formulation: The United States tablet label covers treatment of alcohol dependence and blockade of the effects of externally administered opioids. Benefit depends on an appropriate addiction-management plan, including professional follow-up and psychosocial support. Other proposed uses of low-dose naltrexone are not established indications in this tablet label. A prescriber must assess recent opioid use before treatment begins.

Safety: Starting naltrexone while opioids remain relevant can precipitate severe withdrawal, sometimes requiring hospital care. Trying to overcome the blockade with large opioid doses can be fatal. Opioid sensitivity may increase after treatment stops or a dose is missed. Nausea, headache, dizziness and tiredness may occur. Liver injury symptoms and new or worsening mood symptoms require medical review. Pregnancy and breastfeeding need an individual benefit-risk assessment.

Drug interactions: Opioid pain medicines, including tramadol, conflict with naltrexone treatment and must be discussed with the treating team. Emergency pain management requires supervised planning rather than self-increasing an opioid dose. Concurrent disulfiram is not ordinarily recommended unless the expected benefit outweighs the potential liver risk. Evidence for many other combinations is limited; a short interaction list must not be interpreted as proof that all unlisted combinations are safe.

Sources

• Naltrexone hydrochloride oral tablets — Sun/Major, United States prescribing information
• WHO Collaborating Centre ATC/DDD Index 2026 — naltrexone

This page provides an English summary of the cited sources. Source check: 30 October 2026. This date records a source check, not a clinical review by a doctor or pharmacist. Follow the current leaflet for your product and seek professional advice for personal treatment.