How It Works

Naltrexone (Vivitrol) is a drug that is used for both alcohol and opioid use disorder (OUD). For those with OUD, it is usually given once a month, by injection. It works by blocking the effects of opioids.

Important Information About Naltrexone Use

• Patients on naltrexone who discontinue use or return to use after a period of abstinence may have a reduced tolerance to opioids. Therefore, taking the same, or even lower doses of opioids used in the past can cause life-threatening consequences.
• If you are taking this medicine, you cannot get high from other opioids because the medication blocks the effects. Sometimes people take large amounts of opioids to try to overcome this block. Do NOT do this! It is VERY dangerous and can cause overdose or death.
• Naltrexone kept at home must be locked in a safe place to prevent accidental use by others, especially children. Visit our Safe Medication Storage and Disposal page for locations of where to take your medicine.
• If you are a woman and are pregnant or breast-feeding, you should NOT take naltrexone. Methadone is a safer choice for mother and child.
• Liver problems are rare but can occur. If you have a preexisting liver condition, your doctor should conduct regular tests on your liver.
• While taking this medication, you should NOT use other opioid medications such as some pain medications, cough syrups, and diarrhea medicines. The medicine will stop these medications from working. You should let doctors and dentists know you cannot have any medications (including shots) that contain opioids.
• While taking this medication, you should NOT use illegal drugs, drink alcohol, or take sedatives, tranquilizers, or other drugs that slow breathing. Taking any of these substances in large amounts along with naltrexone can lead to overdose or death.