Talk with your healthcare provider prior to taking naltrexone if you have:
- Used a narcotic (opioid), alcohol, or street drug in the last 7 to 10 days
- Liver disease, such as cirrhosis, liver failure, or hepatitis
- Kidney disease, such as kidney failure (renal failure)
- Depression or have had depression in the past
- Had thoughts of suicide or harming yourself
- Symptoms of drug or alcohol withdrawal
- Any allergies, including to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Revia and Pregnancy)
- Breastfeeding (see Revia and Breastfeeding).
Make sure to tell your healthcare provider about all of the medicines you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
(Click Precautions and Warnings With Naltrexone to learn more, including information on who should not take the drug.)
Naltrexone is an opioid receptor antagonist. It binds to opioid receptors, but does not produce any effects. Instead, it blocks the receptors, preventing other substances (called opioid agonists) from binding to and activating the receptors. This blocks the effects of opioid agonists, such as narcotic pain medications and heroin, so that people who use them will not get the "high" feeling that can reinforce opioid abuse. This can help prevent relapse in people who have stopped using opioids.
It is not entirely clear how naltrexone works to treat alcohol dependence. It is thought that by blocking opioid receptors, naltrexone also helps prevent the rewarding effects of alcohol use, which can reduce the desire to consume alcohol.
Naltrexone is not a narcotic medication. It is also not addictive and does not cause dependence.