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Naltrexone
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Naltrexone Injection

Generic name: naltrexone (injection) [ nal-TREX-own ]
Brand name: Vivitrol
Dosage form: intramuscular powder for injection, extended release (380 mg)
Drug classes:Antidotes, Drugs used in alcohol dependence

Medically reviewed by Philip Thornton, DipPharm. Last updated on May 24, 2021.

What is naltrexone?

Naltrexone blocks the effects of opioid medication, including pain relief or feelings of well-being that can lead to opioid abuse. An opioid is sometimes called a narcotic. Vivitrol is used as part of a treatment program for drug or alcohol dependence.

Naltrexone injection is used to prevent relapse in adults who became dependent on opioid medicine and then stopped using it. Naltrexone can help keep you from feeling a "need" to use the opioid.

Naltrexone injection is also used to treat alcoholism by reducing your urge to drink alcohol. This may help you drink less or stop drinking altogether. You should not be drinking at the time you receive your first injection.

Naltrexone is not a permanent cure for drug addiction or alcoholism.

Warnings

You should be treated with naltrexone only if you have not recently used: any opioid medicine, buprenorphine, methadone, or medicine to treat a cold, cough, diarrhea, or pain. Using these medicines in the 7 to 14 days before starting naltrexone can cause sudden opioid withdrawal symptoms.

Do not use opioid medication, heroin, or other street drugs while you are receiving this medicine. Doing so could result in dangerous effects, including coma and death.

Call your doctor if you have ongoing or worsening pain, redness, itching, bruising, swelling,...