Naltrexone injection is a drug that is used in conjunction with other methods of treating alcohol and opioid disorders. The drug has become one of the most effective pharmaceutical treatments for alcohol use disorders because it reduces the chemical effects of alcohol on the brain. It may also be effective in treating opioid addiction, but caution should be exercised as the combination with even low doses of opioid drugs can be potentially life-threatening...
Naltrexone can be prescribed for a number of different uses. These include:
- Alcohol addiction: Naltrexone is one of only three drugs approved for the treatment of alcohol addiction and has been used for years to help people who have already stopped drinking prevent relapse.
- Opioid addiction: Naltrexone was also effective in treating people who have become addicted to prescription opioids and heroin. It is being researched for the treatment of cocaine use disorders. It works in these conditions by blocking the effects of opioids on the pleasure centers of the brain.
- Other uses: At lower doses, naltrexone is also used to treat pain caused by conditions such as fibromyalgia.and chronic fatigue syndrome...
Advantages of a monthly injection over a daily pill
Naltrexone is available as both a daily pill and a monthly injection. While both drugs are effective, a long-lasting injection once a month offers some clear benefits.
Daily naltrexone pill
For the treatment of alcohol use disorder, naltrexone was originally prescribed as a daily pill, which was usually taken over a period of about 12 weeks. Naltrexone in pill form – marketed as ReVia and Depade – is still widely used.
However, there is an inherent problem with the pill form of naltrexone: it has to be taken every day for it to work. For those struggling with the effects of alcohol withdrawal and alcohol use disorder, adhering to a daily dose can be problematic. It’s easy to forget to take a dose, accidentally take two doses, or intentionally skip them because of the nausea associated with alcohol withdrawal.
It was also the pill form of naltrexone that was originally approved for the treatment of opioid use disorders. While the pill does not create tolerance, it is not ideal because of poor treatment compliance. Because of this, there is little evidence of its benefits in reducing opioid use...
Monthly naltrexone injection
The Food and Drug Administration approved the once-a-month naltrexone treatment marketed as Vivitrol for the treatment of alcohol addiction in 2006. This form of naltrexone could be injected once and slowly released into the system for a month. In 2010, the FDA also approved the use of Vivitrol to treat people with opioid addiction...
Research has shown that once a month naltrexone is effective at reducing alcohol consumption..For opioid use disorders, the injectable, extended-release form of naltrexone is preferred as it only requires one injection per month. Research suggests that this leads to better drug adherence...
Before you start treatment with injectable naltrexone, your doctor will do a physical exam, determine how well your liver is working, and do a drug test. Because naltrexone is an opioid antagonist, if you have been taking opioid medication within the last 10 days, it may result in opioid withdrawal...
It is important to be opioid-free for a period of time before receiving naltrexone injections...
Precautions and Contraindications
You should not receive monthly naltrexone injections or take any other naltrexone-containing medication if you are actively using opioids. The Substance Abuse and Mental Health Authority (SAMHSA) says people treated with naltrexone may have decreased tolerance to opioids.
This can lead to potentially life-threatening consequences if people take opioids in the same amount as they were previously used. Accidental overdose can result, which can result in death...
Because the injectable drug bypasses the liver’s first pass metabolism, the injectable form may reduce the risk of liver toxicity..However, the Food and Drug Administration (FDA) warns of possible liver toxicity if naltrexone is taken in concentrations higher than the recommended dose. Monthly naltrexone injections should not be used by people with acute hepatitis or liver failure...
How you take it
If you think you may have an alcohol or opioid disorder, or want to limit your consumption, talk to your doctor about your treatment options. Your doctor will do a health assessment and will need to determine if a monthly naltrexone injection is right for you.
If your doctor determines that this approach might be appropriate, your doctor will give you an intramuscular injection in the gluteal muscles every four weeks. Medication compliance may be easier than taking a daily pill, as it only requires one injection per month...
The side effects of monthly naltrexone injections are similar to those of daily oral naltrexone. Possible side effects can be:
- stomach pain
- Back pain
- Decreased appetite
- a headache
- Injection site reactions
- Joint pain
In a large study of the use of naltrexone to treat alcohol use disorders, 14.1% of those who took a dose of 380 milligrams stopped treatment because of side effects such as nausea, headache, and fatigue. Only 6.7% of the group who received 190 milligrams stopped treatment because of undesirable side effects...
The study was one of the largest studies involving subjects treated with drugs for alcohol addiction. The researchers concluded that extended-release naltrexone was well tolerated and significantly reduced heavy drinking in actively drinking subjects.
In some cases, serious side effects can also occur. These can be:
- Allergic reaction
- Feelings of depression
- Liver damage
- Injection site reactions (which can be serious and require intervention)
- Suicidal thoughts or behavior
If you have thoughts of suicide, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for the support and assistance of a trained advisor. If you or a loved one is in imminent danger, call 911.
If you are taking naltrexone for the treatment of alcohol or opioid disorders, you should see a doctor immediately if signs of a serious allergic reaction occur, including difficulty breathing, difficulty swallowing, or swelling of the mouth, face, or hands.
Research suggests that naltrexone may be effective in both alcohol use disorder and opioid use disorder.
Naltrexone, used to treat alcohol use disorders
One study found that injecting a 380 mg dose of naltrexone reduced the number of days of heavy drinking by 25%, while a 190 mg dose reduced days of heavy drinking by 17%...
Research suggests that men may be more responsive to treatment with naltrexone than women, and that those who start treatment after a period of drug or alcohol abstinence may have greater treatment effects. The long-acting form of naltrexone can improve treatment strategies for people with alcohol addiction by eliminating the problem of drug adherence.
Naltrexone, used to treat opioid use disorders
A study examining the effectiveness of monthly naltrexone for treating opioid use disorders found that the drug significantly improved abstinence from opioids. Participants treated with a monthly injection of naltrexone were on average abstinent 90% of the weeks during the study, compared with only 35% abstinence in the placebo group. In addition to improved abstinence, those in the naltrexone group also reported decreased drug cravings and had fewer drug relapses...
If you or a loved one is struggling with substance use or addiction, contact the National Substance Abuse and Mental Health Agency (SAMHSA) helpline at 1-800-662-4357 Information about support and treatment facilities in your area.
Additional mental health resources can be found in our National Helpline Database.