Naltrexone Treatment for Opioid and Alcohol Use Disorders

Naltrexone is a prescription medication used to treat alcohol use disorder (AUD) and opioid use disorder (OUD).¹ It works differently from medications such as methadone and buprenorphine because it blocks opioid receptors instead of activating them.¹ Naltrexone is not an opioid, does not produce a high, and is not considered addictive.¹

Naltrexone is generally used as part of a comprehensive treatment plan that may also include counseling, behavioral therapies, medical care, and recovery support.¹ If you're exploring medications as part of treatment, learning more about medication-assisted treatment for addiction can help you understand how naltrexone fits alongside other medication options.

What Is Naltrexone?

Naltrexone is a prescription medication used as part of treatment for alcohol use disorder (AUD) and opioid use disorder (OUD).¹ It belongs to a class of medications called opioid antagonists, which block the activation of opioid receptors in the brain.¹

Naltrexone is not an opioid and does not produce a high.¹ It is also not considered addictive, does not cause physical opioid dependence, and does not cause withdrawal symptoms when treatment is stopped.¹

Naltrexone is available in different forms depending on how it is being used. Oral naltrexone is FDA-approved for alcohol dependence, while extended-release injectable naltrexone, sold under the brand name Vivitrol, is FDA-approved for alcohol dependence and for preventing a return to opioid dependence after opioid detoxification.^2,3

Naltrexone does not treat acute withdrawal.¹ People with OUD must be opioid-free for a period of time before starting naltrexone treatment to avoid precipitating withdrawal.^1,3

How Does Naltrexone Work for Addiction?

Naltrexone works by blocking the activation of opioid receptors in the brain. This directly blocks the euphoric effects of opioid drugs while also modulating brain reward pathways to reduce some of alcohol's reinforcing effects.^1,3,4 Its role differs depending on whether it is being used to treat alcohol use disorder or opioid use disorder.

How Naltrexone Works for Opioid Use Disorder

For opioid use disorder (OUD), naltrexone blocks the effects of opioids such as heroin and prescription opioid medications.^1,3 When these receptors are blocked, opioids are less able to produce their usual euphoric and sedating effects.^1,3

This can help support continued abstinence because using opioids while naltrexone is active does not produce the expected rewarding effects.³

Naltrexone may also help reduce opioid cravings for some patients.¹ People considering medication as part of recovery can also explore broader opioid addiction treatment options, including different levels of care and treatment approaches.

Naltrexone does not treat opioid withdrawal symptoms and should not be started while a patient is still physically dependent on opioids.^1,3 Taking it too soon after stopping opioids can trigger sudden and severe withdrawal.^1,3 For this reason, patients typically need to wait at least seven days after stopping opioids before starting naltrexone.¹

Patients typically need to wait at least seven days after stopping short-acting opioids (e.g., hydrocodone, morphine, oxycodone) and 10 to 14 days after stopping long-acting opioids (e.g., methadone, buprenorphine, or extended-release versions of short-acting opioids) before starting naltrexone.¹

Learn more about drug and alcohol withdrawal and when additional medical support may be needed.

How Naltrexone Works for Alcohol Use Disorder

For alcohol use disorder (AUD), naltrexone blocks opioid receptors involved in the brain’s reward pathways, reducing some of the pleasurable effects associated with drinking and potentially decreasing alcohol cravings.^1,4 Although its exact mechanism in AUD isn’t fully understood, the brain’s opioid system appears to play an important role.³

By making drinking feel less rewarding, naltrexone may help people reduce heavy drinking or work toward other treatment goals.⁴ Research has also found that extended-release naltrexone can reduce drinking days and heavy-drinking days compared with placebo.⁵ People exploring their options can learn more about alcohol addiction treatment, including available programs and levels of care.

For both alcohol addiction and OUD, naltrexone addresses specific biological aspects of addiction rather than every factor that contributes to substance use.¹ It is generally used as part of a broader treatment plan that may include behavioral therapy, counseling, medical care, and recovery support.¹

Oral Naltrexone vs. Vivitrol

Naltrexone is available in oral and extended-release injectable forms, but their FDA-approved uses differ.^2,3

Oral naltrexone is taken as a daily tablet.² It is FDA-approved as part of treatment for alcohol dependence.² Consistent daily dosing of oral naltrexone is important for maintaining its therapeutic effects for people in recovery.

Extended-release naltrexone, sold under the brand name Vivitrol, is given as an intramuscular injection by a healthcare professional approximately once every four weeks.³ Vivitrol is FDA-approved for alcohol dependence and for preventing relapse to opioid dependence after opioid detoxification.³

The appropriate formulation depends on factors such as the condition being treated, medical history, treatment goals, and a patient's ability to follow a daily medication schedule or attend monthly injection appointments.

What Are the Side Effects of Naltrexone?

Like other prescription medications, naltrexone can cause side effects. Common and more serious risks can vary depending on whether a patient takes oral naltrexone or extended-release injectable naltrexone.

• Common oral side effects: Nausea, headache, dizziness, fatigue, insomnia, vomiting, and anxiety have been reported with oral naltrexone.²
• Common Vivitrol side effects: Extended-release injectable naltrexone may cause nausea, vomiting, dizziness, decreased appetite, muscle cramps, and injection-site reactions.³
• Precipitated withdrawal: Starting naltrexone while a patient is still physically dependent on opioids can trigger sudden, severe withdrawal.^1,3 Patients with OUD generally need to be opioid-free before treatment begins.^1,3
• Injection-site reactions: Vivitrol can cause pain, swelling, or redness where it is injected.³ Rarely, more serious reactions may require medical or surgical treatment.³
• Liver problems: Liver injury has been reported during naltrexone treatment.²,³ Symptoms such as persistent abdominal pain, dark urine, or yellowing of the skin or eyes should be evaluated by a healthcare professional.²,³
• Serious allergic reactions: Hypersensitivity reactions, including anaphylaxis, have been reported with Vivitrol.³ Signs of a severe allergic reaction require emergency medical care.

A healthcare provider may review your medical history, medications, opioid use, liver health, and other factors before prescribing naltrexone.^2,3

Naltrexone and Opioid Overdose Risk

People taking naltrexone for OUD should understand the potential risk of opioid overdose.

Trying to overcome naltrexone's opioid-blocking effects by taking large amounts of opioids can cause serious injury, overdose, coma, or death.³

A person's tolerance to opioids can also decrease during a period of abstinence or naltrexone treatment.^1,3 After naltrexone wears off or treatment is stopped, a dose of opioids that someone previously tolerated may increase the risk of overdose.^1,3

Patients receiving naltrexone for OUD should discuss overdose prevention and other safety measures with their healthcare team, including access to naloxone and ensuring that family members or others close to them know how to recognize and respond to an opioid overdose.

Who Should Not Take Naltrexone?

People should not start naltrexone while actively using opioids, while physically dependent on opioids, or while experiencing acute opioid withdrawal.^1,2,3 Starting naltrexone in these situations can cause severe precipitated withdrawal.^1,3

Healthcare professionals may also consider physical dependence, liver health, and other medical conditions when determining whether naltrexone is appropriate.^2,3

Patients should tell their healthcare provider about all medications they take because some prescription pain medications, cough medicines, and other products may contain opioids.¹

How Long Do You Take Naltrexone?

There is no single length of naltrexone treatment that is appropriate for everyone.¹ Treatment duration can depend on factors such as the condition being treated, response to medication, recovery progress, side effects, and treatment goals. For AUD, treatment often lasts several months, although some people may benefit from longer-term naltrexone use.¹

A healthcare provider can help determine how long naltrexone should remain part of a treatment plan. Patients should not change or stop prescribed medication without discussing it with their healthcare provider.

How Is Naltrexone Used as Part of Addiction Treatment?

Naltrexone is generally used as one component of a comprehensive addiction treatment plan.^1,3 Medication may help address cravings or the rewarding effects associated with substance use, while other services can address behavioral, psychological, medical, and social factors involved in recovery.¹

Depending on the patient’s individual needs, treatment may include:

• Medical assessment and medication management
• Individual or group counseling
• Behavioral therapies
• Treatment for co-occurring mental health conditions
• Peer or mutual-support programs
• Outpatient, intensive outpatient, residential, or other levels of care
• Ongoing recovery and relapse-prevention support

The appropriate combination of services depends on factors such as the severity of the substance use disorder, physical and mental health needs, treatment goals, recovery environment, and available support. If you're still determining what type of care might fit your needs, learning about addiction treatment options can help you understand how detox, outpatient treatment, residential care, and other approaches may fit into recovery.

How to Find Treatment That Offers Naltrexone

Naltrexone may be prescribed in outpatient medical settings and may also be offered as part of a structured addiction treatment program.¹ The most appropriate setting depends on the patient's medical needs, substance use, withdrawal risk, treatment goals, and level of support.

When comparing programs, consider asking whether the center:

• Offers medications for alcohol or opioid use disorder, including oral naltrexone or extended-release injectable naltrexone (Vivitrol)
• Has qualified healthcare professionals who can prescribe and monitor medications
• Provides behavioral therapy alongside medication when appropriate
• Can provide or coordinate detox and opioid withdrawal management before naltrexone, when necessary
• Treats co-occurring mental health conditions
• Accepts your insurance or provides clear information about treatment costs

You can explore rehab centers offering medication-assisted treatment to compare programs that offer medication as part of addiction care. If cost is an important part of your decision, learning how much rehab costs can help you understand common expenses and payment options.

Explore Your Addiction Treatment Options

Naltrexone can be one part of treatment for alcohol use disorder or opioid use disorder.¹ Whether it is appropriate depends on factors such as the substance being treated, recent opioid use, medical history, treatment goals, and other individual needs.^1,3

A healthcare provider or treatment team can help determine whether naltrexone or another medication is appropriate for you.

If you're considering treatment, you can compare addiction treatment centers based on location, levels of care, treatment approaches, insurance, and other factors that matter to you.