Naltrexone is an opioid antagonist and primarily used to manage alcohol or opioid dependence. 

It reduces the effect of opioid analgesics (analgesic, antidiarrheal, antitussive); eliminates the side effects of opioids (including endogenous ones), with the exception of the symptoms caused by the histamine response. In alcoholism, it binds to opioid receptors and blocks the effects of endorphins. Reduces the need for alcohol and prevents relapses within 6 months after a 12-week course of therapy (the success of treatment depends on the consent of the patient). Prolonged appointment does not cause tolerance and dependence. Onset of action - after 1-2 hours.

A low dose of naltrexone (up to 4.5 mg per day taken orally) is recommended by some doctors for use in autoimmune diseases such as Crohn's disease and multiple sclerosis. 

According to the anecdotal reports, naltrexone can be used to alleviate the symptoms of antisocial personality disorder in men and borderline personality disorder in women.  These statements have not been evaluated by the FDA. 

An opioid-dependent person should not receive naltrexone before detoxification. In those still on opioids, opioid withdrawal may occur.

This is not FDA-approved product

Dosage and administration

Recommended dosage of Naltrexone is 50mg per day in alcoholism and opioid usage both.

In opioid-depended cases treatment can be started after abstinence from taking drugs for 7-10 days. The patient should not have any withdrawal symptoms. The initial dose is 25 mg, the patient is observed for 1 hour; in the absence of withdrawal, the remaining daily dose is administered. The average dose is 50 mg per day, sufficient for blocking parenterally administered opiates (this dose blocks 25 mg of heroin administered intravenously).

Possible side effects

  • trouble sleeping
  • anxiety
  • nausea
  • headaches
  • diarrhea and abdominal cramping


Hypersensitivity to ingredients of the drug, age below 18 years old, pregnancy and lactation.

Use is not recommended in people with liver failure.