Naltrexone is a medication approved to help people with opioid or alcohol use disorder refrain from misusing these substances. Using naltrexone for opioid use disorder (OUD) blocks the effects of other opioids, so they do not induce pleasurable feelings. For the most effective OUD treatment, access naltrexone through in-person or online medication-assisted treatment programs.

If you are interested in virtual medication-assisted treatment for opioid use disorder, reach out to Confidant Health. Our team is here to provide you with safe, effective online naltrexone treatment for OUD. Schedule a virtual assessment today to determine if naltrexone for opioid use disorder is right for you.

What Is Naltrexone?

Naltrexone is an FDA-approved medication used for the treatment of opioid and alcohol use disorder. It is an opioid antagonist that blocks the euphoric effects of opioids and alcohol to help people overcome dependence on these substances. Since naltrexone is not classified as a controlled substance by the U.S. Drug Enforcement Agency (DEA), it can be prescribed by any provider. However, for optimal results, naltrexone treatment should be combined with counseling as part of a comprehensive treatment program for opioid use disorder. This care approach is also known as medication-assisted treatment or MAT.

Composition of Naltrexone

The Naltrexone composition is quite simple. Oral naltrexone consists of tablets made from naltrexone hydrochloride. Injectable naltrexone (XR-NTX) comes in two parts: a vial of dry powdered naltrexone and a vial of a liquid diluting agent, somewhat like water. Your provider mixes the powder and liquid just before administering your prescribed injection. 

How Does Naltrexone Work?

Naltrexone does not produce mild euphoria. Instead, its primary purpose is to prevent other opioids from providing feelings of euphoria that reinforce misuse. As an opioid antagonist, naltrexone binds to opioid receptors in the brain to block other opioids from attaching to these receptors. This helps weaken the positive association with opioids, so you feel less motivated to misuse them.

Although naltrexone is effective at blocking other opioids from binding to brain receptors, high doses of opioid drugs can possibly override the opioid-blocking effects of naltrexone. 

Naltrexone for Opioid Use Disorder

Since naltrexone must be administered after opioid withdrawal is complete, it cannot help alleviate withdrawal symptoms. The purpose of naltrexone for opioid use disorder is to reduce the risk of relapse by mitigating the pleasurable effects of opioids and reducing motivation to misuse. This medication is one component of a comprehensive treatment plan for opioid use disorder. 

However, there are other medications approved to minimize opioid withdrawal symptoms, such as Suboxone. If you're concerned about withdrawal discomforts, speak to your provider about the best plan of action to address withdrawal, cravings, co-occurring mental health conditions, and long-term recovery needs. 

Administration of Naltrexone

The proper administration of naltrexone is essential for a successful treatment outcome. Administering naltrexone too soon after opioid use can result in precipitated opioid withdrawal. 

Your provider will have you wait approximately 7 to 10 days after the last use of short-acting opioids like codeine and oxycodone and 10 to 14 days after the last use of long-acting opioids like extended-release morphine and fentanyl transdermal patches.

Then, they can safely administer your first dose of naltrexone. This waiting period allows opioids to leave your system before introducing naltrexone, helping to prevent complications with precipitated opioid withdrawal.

Naltrexone Prescription

Whether you are prescribed oral or injectable naltrexone, your provider may perform a naloxone challenge test or a urine test to check that opioids are no longer in your system. This is important to help prevent precipitated opioid withdrawal symptoms caused by initiating naltrexone treatment too soon after the last opioid use.

Oral Naltrexone

Treatment with oral naltrexone may only begin after you are abstinent from opioids for seven to 14 days to ensure that withdrawal symptoms are finished. 

Oral Naltrexone is delivered in tablet form and works to block the effects of opioids for one to two days.


Naltrexone tablets come in 50 mg pills. Your provider may customize your dose based on your needs, but the typical dosage for oral naltrexone induction is 50 mg for the first day. Your provider will have you take 25 mg, half a tablet, initially. After about an hour, they will instruct you to take the other half of the tablet, another 25 mg.

After the first day, the typical dosage is 350 mg per week, divided as instructed by your provider. There are several oral naltrexone dosage schedules that providers follow:

  • One 50 mg tablet daily

  • Two 50 mg tablets every other day

  • Three 50 mg tablets every three days

  • One 50 mg tablet on weekdays and two 50 mg tablets on Saturdays, skipping Sundays

Your provider will determine which of these naltrexone dosage schedules is most appropriate for you.

Injectable Naltrexone (XR-NTX)

Injectable naltrexone can only be administered once opioid withdrawal symptoms are gone, approximately seven to 14 days after the last opioid use.

Naltrexone injections are administered by your provider once a month. The extended-release formula helps to block the effects of opioids for four weeks.


Injectable naltrexone comes as a single 380 mg dose administered in your provider's office once a month.

FAQs about Naltrexone for Opioid Use Disorder

Is naltrexone the same as Suboxone?

Naltrexone and Suboxone are both FDA-approved medications for opioid use disorder, but they function differently. Naltrexone is an opioid antagonist that interacts with opioid receptors to block the effects of opioids. Suboxone contains buprenorphine and naloxone. Naloxone is also an opioid antagonist that blocks the effects of opioids, but buprenorphine is a partial opioid agonist that imparts mild euphoria to mitigate uncomfortable withdrawal symptoms and cravings. 

Another difference between naltrexone and Suboxone is when they are administered. Suboxone plays an important role in alleviating withdrawal symptoms, so it is administered early in treatment. On the other hand, naltrexone must be administered after symptoms of opioid withdrawal have dissipated. Since timing is crucial for the administration of these OUD medications, you should consult with a qualified provider for treatment.

Can you get high on naltrexone?

You cannot get high on naltrexone. As an opioid antagonist, naltrexone blocks the pleasurable effects of opioids and does not produce any euphoric effects of its own.

When was naltrexone FDA approved?

Oral naltrexone was approved by the Food and Drug Administration (FDA) in 1984 for the purpose of blocking the euphoric effects of opioids. Injectable extended-release naltrexone (XR-NTX) was approved by the FDA in 2010 to help prevent relapse after opioid withdrawal.

Access Naltrexone for OUD with Confidant Health

Online medication-assisted treatment for OUD allows you to recover in the privacy and comfort of your home. To find out if virtual medication-assisted treatment for opioid use disorder is suitable for your situation, contact the professionals at Confidant Health.