Drugs Home > Precautions and Warnings With Naltrexone

Prior to prescribing naltrexone, your healthcare provider will ask about your medical history and all other drugs you are taking. This will include any street drugs or alcohol you might have had in the last 7 to 10 days. Reviewing safety precautions such as these can help prevent dangerous drug interactions with naltrexone. Other warnings apply to people who have liver disease, kidney disease, or certain other medical conditions.


What Should I Tell My Healthcare Provider?

Talk with your healthcare provider prior to taking naltrexone (Revia®) if you have:
  • Used a narcotic (opioid), alcohol, or street drug in the past 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.
In addition, let your healthcare provider know if you are:
  • Breastfeeding
  • Pregnant or thinking of becoming pregnant.
You should also tell your healthcare provider about all other medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.

Specific Naltrexone Precautions and Warnings

Some warnings and precautions to be aware of prior to taking naltrexone include the following:
  • You should carry identification, such as a medical card or medical bracelet, to alert medical personnel that you are being treated with naltrexone. This will help ensure you receive appropriate care in the case of an emergency. You can get a medical card from your healthcare provider.
  • Naltrexone may cause liver damage, especially when taken in higher-than-recommended doses. Let your healthcare provider know if you develop liver problems during treatment, such as:
    • Abdominal (stomach) pain
    • Pale-colored stool
    • Dark urine
    • Yellowing of the skin or whites of the eyes (jaundice).
  • This medicine can cause withdrawal symptoms when taken with opioids. Therefore, you must be opioid free, including prescription narcotic medications and heroin, for 7 to 10 days (for most opioids) before starting treatment. For long-acting opioids such as buprenorphine or methadone, you need to wait an even longer time (two weeks) before starting naltrexone. Your healthcare provider may want to do certain tests, such as a urine test, to check for opioids in your system. Let him or her know if you are having symptoms of opioid withdrawal, such as:
    • Anxiety or restlessness
    • Insomnia
    • Yawning
    • Sweating
    • Excessive watering of the eyes
    • Runny nose
    • Goosebumps
    • Fever, shaking, and chills
    • Muscle aches
    • Nausea and vomiting
    • Abdominal (stomach) cramps.
Opioid withdrawal caused by naltrexone can be much more severe than "normal" opioid withdrawal. Normal symptoms can be extremely unpleasant, but are not usually dangerous. Opioid withdrawal caused by naltrexone, on the other hand, may be serious enough to require hospitalization.
  • Naltrexone blocks the effects of opioids, including the "high" feelings and the pain-relieving effects. Do not try to overcome this by taking large amounts of opioids or heroin, as doing so is extremely dangerous and may result in a coma or death.
  • Because this drug blocks the effects of opioids, if you need medication for pain, cough, or diarrhea during treatment, you will need to take a nonopioid-containing medicine.
  • You may be more sensitive to the effects of opioids after you have been treated with naltrexone. Using opioids in the amounts you used before treatment could cause serious harm, including death. Make sure your healthcare providers know if you have been treated with naltrexone, even after treatment is complete.
  • This medication should be used cautiously in people with liver or kidney disease. Make sure your healthcare provider knows if you have these conditions.
  • People with substance abuse are at an increased risk for suicide, and naltrexone does not reduce this risk. Please seek immediate help if you have suicidal thoughts or thoughts of hurting yourself or ending your life.
  • This medication is just one part of a comprehensive treatment program for drug or alcohol dependence. Your healthcare provider may recommend other types of treatment, such as counseling or support groups. 
  • Naltrexone passes through breast milk. Therefore, if you are breastfeeding or plan to start, you should discuss this with your healthcare provider prior to taking the drug (see Revia and Breastfeeding).
  • Naltrexone is a pregnancy Category C medication, which means it may not be safe for use during pregnancy, although the full risks are currently unknown (see Revia and Pregnancy).
Written by/reviewed by:
Last reviewed by: Kristi Monson, PharmD;
Last updated/reviewed:
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