Class Name(s):

• 28:10 Opiate Antagonists

Pronunciation:

• (nal trex' one)

Brand Name(s):

• ReVia^®; also available generically

IMPORTANT WARNING:

Naltrexone may cause liver damage when taken in large doses. It is not likely that naltrexone will cause liver damage when taken in recommended doses. Tell your doctor if you have or have ever had hepatitis or liver disease. If you experience any of the following symptoms, stop taking naltrexone and call your doctor immediately: excessive tiredness, unusual bleeding or bruising, loss of appetite, pain in the upper right part of your stomach that lasts more than a few days, light-colored bowel movements, dark urine, or yellowing of the skin or eyes.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain laboratory tests to check your body's response to naltrexone.

Talk to your doctor about the risks of taking naltrexone.

WHY is this medicine prescribed?

Naltrexone is used along with counseling and social support to help people who have stopped drinking alcohol and using street drugs continue to avoid drinking or using drugs. Naltrexone should not be used to treat people who are still using street drugs or drinking large amounts of alcohol. Naltrexone is in a class of medications called opiate antagonists. It works by decreasing the craving for alcohol and blocking the effects of opiate medications and opioid street drugs.

HOW should this medicine be used?

Naltrexone comes as a tablet to take by mouth either at home or under supervision in a clinic or treatment center. When naltrexone is taken at home, it is usually taken once a day with or without food. When naltrexone is taken in a clinic or treatment center, it may be taken once a day, once every other day, once every third day, or once every day except Sunday. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take naltrexone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Naltrexone is only helpful when it is used as part of an addiction treatment program. It is important that you attend all counseling sessions, support group meetings, education programs, or other treatments recommended by your doctor.

Naltrexone will help you avoid using drugs and alcohol, but it will not prevent or relieve the withdrawal symptoms that may occur when you stop using these substances. Instead, naltrexone may cause or worsen withdrawal symptoms. You should not take naltrexone if you have recently stopped using opioid medications or opioid street drugs and are now experiencing withdrawal symptoms.

Naltrexone will help you avoid drugs and alcohol only as long as you are taking it. Continue to take naltrexone even if you feel well. Do not stop taking naltrexone without talking to your doctor.

Are there OTHER USES for this medication?

This medication may be sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before taking naltrexone,

• tell your doctor and pharmacist if you are allergic to naltrexone naloxone, other opioid medications, or any other medications.
• tell your doctor if you are taking any opioid (narcotic) medications or street drugs including levomethadyl acetate (LAAM, ORLAAM) (not available in the US), or methadone (Dolophine, Methadose); and certain medications for diarrhea, cough, or pain. Also tell your doctor if you have taken any of these medications in the past 7 to 10 days. Ask your doctor if you are not sure if a medication you have taken is an opioid. Your doctor may order certain tests to see if you have taken any opioid medications or used any opioid street drugs during the past 7 to 10 days. Your doctor will tell you not to take naltrexone if you have taken or used opioids in the past 7 to 10 days.
• do not take any opioid medications or use opioid street drugs during your treatment with naltrexone. Naltrexone blocks the effects of opioid medications and opioid street drugs. You may not feel the effects of these substances if you take or use them at low or normal doses. If you take or use higher doses of opioid medications or drugs during your treatment with naltrexone, it may cause serious injury, coma (long-lasting unconscious state), or death.
• you should know that if you took opioid medications before your treatment with naltrexone, you may be more sensitive to the effects of these medications after you finish your treatment. After you finish your treatment, tell any doctor who may prescribe medications for you that you were previously treated with naltrexone.
• some medications should not be taken with naltrexone. Other medications may cause dosing changes or extra monitoring when taken with naltrexone. Make sure you have discussed any medications you are currently taking or plan to take before starting naltrexone with your doctor and pharmacist. Before starting, stopping, or changing any medications while taking naltrexone, please get the advice of your doctor or pharmacist.
• tell your doctor if you have or have ever had depression or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking naltrexone, call your doctor.
• if you need medical treatment or surgery, including dental surgery, tell the doctor or dentist that you are taking naltrexone. Wear or carry medical identification so that healthcare providers who treat you in an emergency will know that you are taking naltrexone.
• you should know that people who overuse drugs or alcohol often become depressed and sometimes try to harm or kill themselves. Receiving naltrexone does not decrease the risk that you will try to harm yourself. You or your family should call the doctor right away if you experience symptoms of depression such as feelings of sadness, anxiousness, hopelessness, guilt, worthlessness, or helplessness, or thinking about harming or killing yourself or planning or trying to do so. Be sure that your family knows which symptoms may be serious so they can call the doctor right away if you are unable to seek treatment on your own.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Naltrexone may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• nausea
• vomiting
• stomach pain or cramping
• diarrhea
• constipation
• loss of appetite
• headache
• dizziness
• anxiety
• nervousness
• irritability
• tearfulness
• difficulty falling or staying asleep
• increased or decreased energy
• drowsiness
• muscle or joint pain
• rash

Some side effects can be serious. If you experience any of these symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately:

• confusion
• hallucinations (seeing things or hearing voices that do not exist)
• blurred vision
• severe vomiting and/or diarrhea

Naltrexone may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location - one that is up and away and out of their sight and reach. http://www.upandaway.org

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website http://goo.gl/c4Rm4p for more information.

What OTHER INFORMATION should I know?

Before having any laboratory tests, tell your doctor and the laboratory personnel that you are taking naltrexone.

Ask your doctor or pharmacist any questions you have about naltrexone.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2025. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: October 15, 2017.