What is naltrexone?

Naltrexone has been approved by the FDA as a treatment to prevent relapse to opioid dependence after the patient has achieved complete opioid detoxification. Naltrexone is best used as a relapse prevention measure after a treatment program that includes counseling has been completed and the patient has tapered completely from opioid maintenance medications. Naltrexone is then prescribed to patients who are able to remain completely free of prescribed opiates for at least seven to 10 days. This process will require the patient to undergo a supervised withdrawal that is called detoxification or detox. Naltrexone can only be started once detox is completed.

Naltrexone is an opioid antagonist. That means it blocks certain receptors, or the sites where opioids work in the brain. The result is that people cannot experience the euphoric effects, or the feeling of being high, from opioids.

For patients who have naltrexone as an option, the key barrier of usage is the cost of the injection which is $1,200 - $1,500 for an injection that is taken once a month. Because a majority of patients with opioid use disorder are already financially burdened, naltrexone may only be an option if there are programs available through Medicaid and commercial insurance to support the cost of the treatment.

How does naltrexone work?

Naltrexone blocks the euphoric and sedative effects of drugs such as heroin, morphine, and codeine.

How should naltrexone be used?

As with all medications in medication-assisted treatment, naltrexone is to be prescribed as part of a comprehensive treatment plan that includes counseling and participation in social support programs.

Is naltrexone similar to methadone and buprenorphine?

While Naltrexone is used to treat opioid use disorder, it works differently in the body than methadone and buprenorphine, which activate opioid receptors in the body that suppress cravings. Naltrexone binds and blocks opioid receptors, and is reported to reduce opioid cravings. There is no abuse and diversion potential with naltrexone.

What happens if a patient relapses?

If a person relapses and uses the problem drug, naltrexone prevents the feeling of getting high.

What should patients using naltrexone avoid?

People using naltrexone should not use any other opioids or illicit drugs, drink alcohol, or take sedatives, tranquilizers or other drugs.

What are the risks associated with using naltrexone?

Patients on naltrexone will have a reduced tolerance to opioids and may be unaware of that lower doses of opioids can have life-threatening consequences. If patients who are treated with naltrexone relapse after a period of abstinence, it is possible that the dosage of opioid that was previously used may result in overdose or death. Patients taking naltrexone should NOT use any illegal drugs, drink alcohol, or take sedatives, tranquilizers or other drugs that slow breathing. Combining any of these substances with Naltrexone can lead to overdose or death.

What are the side effects of naltrexone?

People taking naltrexone may experience side effects, but they should not stop taking the medication. Instead, they should consult their health care provider or substance misuse treatment practitioner.

Some side effects include:

  • Diarrhea
  • Headache
  • Nervousness
  • Sleep problems/tiredness
  • Joint or muscle pain
  • Upset stomach or vomiting

According to SAMHSA, seek a health care provider right away with any of the following symptoms:

  • Liver injury: Naltrexone may cause liver injury; seek evaluation if you have symptoms and or signs of liver disease.
  • Injection site reactions: This may occur from the injectable naltrexone; seek evaluation for worsening skin reactions.
  • Allergic pneumonia: It may cause an allergic pneumonia; seek evaluation for signs and symptoms of pneumonia.

For More Information on Naltrexone

If you think naltrexone treatment would be a good solution for your rehabilitation, contact a New Season treatment provider at 1-877-284-7074 or

Am I a Candidate for Naltrexone?

Naltrexone is available to patients who are opioid-free for at least 7 to 10 days to avoid sudden opioid withdrawal. If you are a woman and are pregnant or breast-feeding, you should NOT take naltrexone. Methadone is safer for mother and child. Patients should also consider the high financial cost associated with this medication, which may or may not be covered by Medicaid or health insurance. Consult your healthcare provider to determine if there are programs available to cover the cost of the medication.

What are the Drawbacks of Naltrexone?

Naltrexone has a few drawbacks, including:

  • Individuals must go through a two-week detox period before starting naltrexone, which could be difficult.
  • Cravings may occur when first starting treatment, but happen less frequently with the monthly injectable form.
  • Some people may experience vomiting, diarrhea, headaches, joint or muscle pain, or sleep problems, which usually decrease as treatment continues.