Naltrexone: What It Does, Uses, and Safety
Naltrexone is a medicine that blocks opioid receptors in the brain. People use it to treat opioid and alcohol dependence. It can stop the feeling of reward from drinking or using opioids, which helps reduce cravings and prevent relapse. Unlike methadone or buprenorphine, naltrexone does not activate opioid receptors — it only blocks them.
There are two common forms: oral naltrexone, taken once daily, and injectable extended-release naltrexone, given monthly. Doctors usually require that opioid withdrawal is complete before starting naltrexone to avoid sudden withdrawal symptoms. For alcohol dependence, patients can begin once they are medically stable and willing to stop drinking.
Low-dose naltrexone (LDN) has become popular off-label for conditions like autoimmune disorders, chronic pain, and fibromyalgia. LDN uses much smaller doses than addiction treatment and may alter immune signaling. Evidence for LDN is mixed: some small studies and patient reports show benefits, but larger trials are limited. If you consider LDN, talk with a doctor experienced in off-label prescribing and track results carefully.
Common side effects include nausea, headache, fatigue, and dizziness. More serious problems can occur, such as liver enzyme elevations, so people with liver disease need close monitoring or should avoid naltrexone. Always check liver tests before and during treatment as your clinician advises.
Naltrexone interacts with opioid painkillers and will block their effects. This matters if you might need opioid pain relief for surgery or injury — you may need to stop naltrexone beforehand or use non-opioid pain management. Also avoid using opioids while on naltrexone; doing so can lead to overdose risk if naltrexone wears off and the usual dose of opioid is taken.
How to take it matters. Swallow oral tablets with water and follow the prescription. For the monthly shot, clinics provide the injection and schedule follow-ups. Missing doses can reduce protection against relapse, but stopping abruptly can also be risky if opioids are subsequently used.
If you use naltrexone for alcohol or opioid dependence, combine it with counseling or support groups. Medications work best alongside therapy and social support. Ask about naloxone if you or someone close uses opioids — naltrexone is not an emergency overdose treatment.
When choosing treatment, consider your goals, medical history, and lifestyle. Naltrexone suits people who want a non-opioid option and who can avoid opioids while on treatment. It may not be right for everyone.
Always consult a healthcare provider before starting naltrexone. They can confirm it’s safe, order liver tests, and help plan follow-up care. If you notice worrying symptoms like severe abdominal pain or yellowing skin, seek medical help right away.
To find help, start with your primary doctor, local addiction clinic, or a pharmacist. Many clinics offer the monthly injection and counseling together. Use trusted websites like government health pages or major hospitals for facts, not forums alone. If you are pregnant, planning pregnancy, or breastfeeding, tell your provider—naltrexone may not be recommended. Keep a list of all medicines and supplements you take to avoid interactions, and bring it to each appointment regularly.
