Generic Name: naltrexone (injection) (nal TREX own)
Brand Name: Vivitrol
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. Naltrexone is used as part of a treatment program for drug or alcohol dependence.
Naltrexone injection is used to prevent relapse in people 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. Naltrexone will not decrease the effects of alcohol you recently consumed. You should not be drinking at the time you receive your first naltrexone injection.
Naltrexone is not a cure for drug addiction or alcoholism.
Naltrexone may also be used for purposes not listed in this medication guide.
You should not receive naltrexone if you are having drug or alcohol withdrawal symptoms, if you have taken any opioid medicine within the past 2 weeks, or if you are still actively drinking alcohol.
Before taking this medicine
You should not receive a naltrexone injection if you still use opioid medicine, or you could have sudden and severe withdrawal symptoms.
You should not receive naltrexone if you are allergic to it, or if:
you are having withdrawal symptoms from drug or alcohol addiction;
To make sure naltrexone is safe for you, tell your doctor if you have:
It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.
Naltrexone can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.
How is naltrexone used?
Naltrexone is injected into a muscle. This injection is usually given once a month (every 4 weeks) and can be given only by a doctor or nurse in a clinic.
It is important to receive your naltrexone regularly to get the most benefit.
You may notice pain, redness, bruising, swelling, or a hard lump where the medicine was injected. Call your doctor if you have this type of reaction to the shot, especially if it does not clear up or gets worse within 2 weeks.
Naltrexone injections are only part of a complete treatment program that may also include additional forms of counseling and/or monitoring. Follow your doctor's instructions very closely.
Wear a medical alert tag or carry an ID card stating that you use naltrexone. Any medical care provider who treats you should know that you are receiving this medication. If you need surgery, tell the surgeon ahead of time that you are receiving naltrexone injections.
After receiving naltrexone, your body will be more sensitive to opioids. If you use an opioid medicine in the future, you will need to use less than before naltrexone treatment. Using the same amount you used before could lead to overdose or death.
What happens if I miss a dose?
Call your doctor for instructions if you miss an appointment to receive your naltrexone injection.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while using naltrexone?
Do not use narcotic medication, heroin, or other street drugs while you are receiving naltrexone. Never try to overcome the effects of naltrexone by taking large doses of opioids. Doing so could result in dangerous effects, including coma and death.
Do not drink alcohol during treatment with naltrexone.
Naltrexone may impair your thinking or reactions. Avoid driving or operating machinery until you know how this medicine will affect you.
Naltrexone side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Using opioid medicine while you are receiving naltrexone injections could stimulate opioid withdrawal symptoms. Common withdrawal symptoms are yawning, irritability, sweating, fever, chills, shaking, vomiting, diarrhea, watery eyes, runny nose, goose bumps, body aches, trouble sleeping, and feeling restless.
Call your doctor at once if you have:
weak or shallow breathing;
confusion, severe dizziness, feeling like you might pass out;
depression, thoughts about suicide or hurting yourself;
severe pain, swelling, blistering, skin changes, a dark scab, or a hard lump where the medicine was injected;
new or worsening cough, wheezing, trouble breathing; or
Common side effects may include:
nausea, vomiting, changes in appetite;
abnormal liver function tests;
sleep problems (insomnia);
stuffy nose, tooth pain; or
pain, swelling, or itching where the injection was given.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
Naltrexone dosing information
Usual Adult Dose for Alcohol Dependence:
50 mg orally once a day
Extended-release injectable suspension:
380 mg every 4 weeks (or once a month) via intramuscular gluteal injection, alternating buttocks
Usual Adult Dose for Opiate Dependence:
Treatment should not be attempted unless the patient has remained free of opioids for at least 7 to 10 days. Opioid abstinence should be verified by analysis of urine for absence of opioids. The patient should not be manifesting withdrawal signs or reporting withdrawal symptoms. If there is any question of occult opioid dependence, perform a naloxone challenge test and do not initiate naltrexone therapy until the naloxone challenge is negative. The naloxone challenge test should not be performed in a patient showing clinical signs or symptoms of opioid withdrawal, or whose urine contains opioids. The naloxone challenge can be repeated in 24 hours.
Initial dose: 25 mg orally one time.
Maintenance dose: If no withdrawal signs occur, 50 mg orally once a day may be started.
Alternative dose schedules: (to improve compliance) 50 mg orally on week days and 100 mg orally on Saturday; or 100 mg orally every other day; or 150 mg orally every third day.
Extended-release injectable suspension: 380 mg every 4 weeks (or once a month) via intramuscular gluteal injection, alternating buttocks
What other drugs will affect naltrexone?
Naltrexone will block the effects of any narcotic medicines you take (such as prescription medicine for pain, cough, or diarrhea). Harmful side effects could also occur.
Other drugs may interact with naltrexone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.
More about naltrexone
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Images
- Drug Interactions
- Compare Alternatives
- Support Group
- Pricing & Coupons
- 283 Reviews – Add your own review/rating
- Drug class: antidotes
- Naltrexone Tablets
- Naltrexone Injection
- Naltrexone (Advanced Reading)
- Naltrexone Intramuscular (Advanced Reading)
Related treatment guides
Where can I get more information?
- Your doctor can provide more information about naltrexone.
- Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
- Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2012 Cerner Multum, Inc. Version: 4.03.
Date modified: March 06, 2018
Last reviewed: August 15, 2015