Table of Contents

Naltrexone: Effective Treatment for Opioid and Alcohol Dependence


Clinically Reviewed by: Dr. Robin Campbell, LMFT, PHD

What is Naltrexone?

Naltrexone hydrochloride is a powerful tool in the fight against opioid addiction and alcohol dependence. It works by blocking the effects of opioid drugs at the mu opioid receptor, effectively reducing opioid cravings and opioid withdrawal symptoms. For those dealing with alcohol use disorder, naltrexone therapy can significantly reduce alcohol craving and help maintain abstinence. Available in both oral and extended release injectable naltrexone forms, this FDA-approved medication is an essential part of many treatment plans. Before starting naltrexone, it is crucial to tell your doctor about any existing conditions, such as liver disease or kidney disease, and discuss any other drugs you are taking. A naloxone challenge test may be required to ensure safety, especially for those who have used opioid street drugs or opioid-containing medicines. Administering naltrexone requires careful medical supervision to avoid serious injury or complications from missed doses. This comprehensive approach is part of a broader treatment improvement protocol endorsed by the Substance Abuse and Mental Health Services Administration.


What is Naltrexone?

Naltrexone is a medication primarily used to manage alcohol dependence and opioid dependence. It works by blocking the effects of opioids and reducing the craving and desire for alcohol. As an opioid antagonist, Naltrexone blocks opioid receptors in the brain, preventing opioids from producing their euphoric effects. This mechanism also reduces the reinforcing effects of alcohol, aiding individuals in decreasing their alcohol consumption. Naltrexone is available in both oral and injectable forms, with the oral form taken daily and the injectable form, known as Vivitrol, administered once a month. Naltrexone can be prescribed by any healthcare provider licensed to prescribe medications, without the need for special training.

Common side effects of Naltrexone include nausea, headache, dizziness, fatigue, and anxiety. Some individuals may experience liver toxicity, making liver function tests necessary before and during treatment. Naltrexone is contraindicated in individuals currently dependent on opioids, as it can precipitate withdrawal symptoms, and in those with acute hepatitis or liver failure. It is essential for individuals to be opioid-free for at least 7-10 days before starting Naltrexone to avoid withdrawal. Regular monitoring by healthcare providers is recommended to ensure safety and efficacy. When combined with counseling and support, Naltrexone can be an effective part of a comprehensive treatment plan to help individuals achieve and maintain sobriety.


Naltrexone Types and Dosages

Naltrexone is a medication primarily used to manage alcohol or opioid dependence. It works by blocking the euphoric and sedative effects of these substances, helping to prevent relapse. There are two main types of naltrexone available, each with different dosages:

  1. Oral Naltrexone

         Brand Name: Revia, Depade

  • Standard Dosage: 50 mg once daily.
  • Alternate Dosage: Sometimes, higher doses like 100 mg every other day or 150 mg every three days may be prescribed, depending on patient needs and medical advice.


  1. Injectable Naltrexone

         Brand Name: Vivitrol

  • Standard Dosage: 380 mg administered intramuscularly once every four weeks or once a month.
  • Formulation: Long-acting injection, which can help improve adherence compared to daily oral tablets.


Additional Notes

  • Administration: Oral tablets are taken with or without food, while the injectable form must be administered by a healthcare professional.
  • Adjustment: Dosages may be adjusted based on individual response, tolerance, and specific treatment goals.
  • Monitoring: Regular monitoring by a healthcare provider is essential to manage potential side effects and ensure the medication’s effectiveness.
  • Missed Dose: If a dose is missed, do not take a double dose to make up for it. Consult your healthcare provider for guidance.


Naltrexone Uses

  1. Alcohol Dependence
  • Purpose: Naltrexone is used to treat alcohol dependence by reducing cravings and helping maintain abstinence from alcohol.
  • Mechanism: Blocks the rewarding effects of alcohol, reducing the desire to drink.


  1. Opioid Dependence
  • Purpose: Prevents relapse in individuals who have been detoxified from opioids.
  • Mechanism: Blocks the euphoric and sedative effects of opioids.


  1. Off-Label Uses
  • Behavioral Disorders: Used to manage self-injurious behaviors, pathological gambling, and certain eating disorders.
  • Chronic Pain Management: In low doses, sometimes used for conditions like fibromyalgia and chronic pain.


Naltrexone for Opioid Use Disorder

Naltrexone is effective in treating opioid use disorder (OUD) by blocking opioid receptors, preventing the euphoric effects of opioids, and reducing cravings. It helps prevent relapse in individuals who have detoxified from opioids. Available in daily oral (50 mg) or monthly injectable (380 mg) forms, naltrexone supports long-term recovery. Common side effects include nausea, headache, and dizziness. It’s most effective when combined with counseling and support programs. Regular monitoring, especially of liver function, is recommended.


How Long Does Naltrexone Stay in Your System?

The half-life of naltrexone varies depending on the form of administration:

Oral Naltrexone

  • Half-Life: Approximately 4 hours.
  • Active Metabolite (6-β-naltrexol): The half-life of this metabolite is about 13 hours.

Injectable Naltrexone (Vivitrol)

  • Half-Life: The extended-release formulation has a half-life of 5 to 10 days due to its gradual release into the bloodstream.

Total Duration in System

  • Oral Naltrexone: Typically stays in the system for about 24-48 hours.
  • Injectable Naltrexone: Can stay in the system for several weeks, up to a month, due to its extended-release properties.


The elimination time can vary based on individual factors like metabolism, age, liver function, and overall health.


How Long is Naltrexone Detectable in Your System?

The detectability of naltrexone in the system depends on several factors, including the form of administration, dosage, metabolism, and the type of drug test used.

Oral Naltrexone

  • Detectable in Blood: Up to 24 hours after the last dose.
  • Detectable in Urine: Typically 4 to 6 days, but can vary based on individual factors.

Injectable Naltrexone (Vivitrol)

  • Detectable in Blood: Due to the extended-release formulation, it can be detectable for up to a month.
  • Detectable in Urine: Can be detectable for several weeks, up to a month.

Factors Affecting Detectability

  • Metabolism: Faster metabolism can reduce detection time.
  • Liver Function: Impaired liver function can extend the presence of naltrexone in the system.
  • Hydration and Urine pH: These can influence the detection window in urine tests.

Drug Testing Types

  • Blood Tests: Typically used to detect recent use, with a shorter detection window.
  • Urine Tests: More common and can detect naltrexone for a longer period compared to blood tests.


How Does Naltrexone Work in the Brain and Body?

Naltrexone works by blocking opioid receptors in the brain and body, making it an effective treatment for opioid and alcohol dependence. As an opioid receptor antagonist, naltrexone binds to these receptors without activating them, preventing opioids like heroin or prescription painkillers from producing their euphoric and sedative effects. This action helps prevent relapse in opioid-dependent individuals. In the case of alcohol dependence, naltrexone reduces the rewarding effects of alcohol, likely by interfering with the release of dopamine in the brain’s reward pathway, thus helping to diminish cravings.

By competitively binding to the same receptors that opioids target, naltrexone prevents these substances from exerting their effects. Unlike opioids, naltrexone does not activate the receptors, which helps prevent the release of dopamine associated with pleasure and addiction. Over time, naltrexone use can lead to upregulation of opioid receptors, making the brain less sensitive to opioids and supporting long-term recovery. Additionally, by reducing the positive reinforcement associated with substance use, naltrexone can aid in behavioral therapies, further supporting individuals in maintaining abstinence from opioids and alcohol. This combined action in both the brain and body helps individuals on their recovery journey by reducing cravings and preventing relapse.


Naltrexone Effects on the Body

Naltrexone has several effects on the body that contribute to its effectiveness in treating opioid and alcohol dependence:

Blocking Opioid Effects

  • Prevention of Euphoria and Sedation: By blocking opioid receptors, naltrexone prevents the euphoric and sedative effects of opioids, which can help in preventing relapse.
  • Reduced Cravings: It diminishes cravings for opioids by ensuring that these substances do not produce the expected pleasurable effects.

Impact on Alcohol Use

  • Diminished Reward Response: Naltrexone interferes with the release of dopamine in response to alcohol consumption, reducing the rewarding effects and thereby helping to curb alcohol cravings and consumption.

General Bodily Effects

  • Receptor Regulation: Continuous use of naltrexone can lead to upregulation of opioid receptors, meaning the body becomes less sensitive to opioids over time.
  • Potential Side Effects: Some common side effects include nausea, headache, dizziness, fatigue, and insomnia. Less commonly, it can cause liver enzyme abnormalities, so liver function monitoring is recommended during treatment.

Immune and Inflammatory Responses

  • Potential Anti-Inflammatory Effects: There is some evidence suggesting that low-dose naltrexone may have anti-inflammatory properties, which can be beneficial in conditions involving chronic inflammation, although this is still under research.

Metabolism and Excretion

  • Processing by the Liver: Naltrexone is metabolized by the liver and excreted primarily in the urine. This processing necessitates regular liver function tests to ensure safe use, especially in long-term treatment.


Naltrexone Efficacy

Naltrexone is effective in treating opioid and alcohol dependence by blocking opioid receptors and reducing cravings. Studies show that it helps prevent relapse in opioid use and reduces heavy drinking in alcohol-dependent individuals. Its efficacy is enhanced when combined with counseling and support programs, making it a valuable component of comprehensive addiction treatment plans. Regular monitoring and adherence to prescribed regimens are crucial for optimal outcomes.


Naltrexone Side Effects and Risks

Short-Term Side Effects

  • Common: Nausea, headache, dizziness, fatigue, insomnia.
  • Less Common: Anxiety, joint or muscle pain, irritability.


Long-Term Side Effects

  • Liver Damage: Potential for liver enzyme abnormalities; regular monitoring is essential.
  • Depression: Some users may experience mood changes or depression.



  • Precipitated Withdrawal: Can cause immediate withdrawal symptoms if taken while opioids are still in the system.
  • Allergic Reactions: Rare but possible, including rash, itching, or swelling.
  • Drug Interactions: Potential interactions with other medications, requiring careful management by a healthcare provider.


Is Naltrexone Addictive?

No, naltrexone is not addictive. It does not produce euphoric or sedative effects and does not lead to dependence or abuse. It is designed to help prevent addiction relapse by blocking the effects of opioids and reducing cravings for alcohol.


Can You Overdose on Naltrexone?

It is unlikely to overdose on naltrexone itself, as it does not produce the euphoric or sedative effects associated with opioid overdose. However, taking higher-than-prescribed doses can increase the risk of side effects, such as liver damage. More critically, using opioids while on naltrexone can lead to an overdose if the user attempts to overcome the blocking effects by taking large amounts of opioids. This can result in severe respiratory depression and potentially fatal consequences. Therefore, it is important to use naltrexone only as prescribed and under medical supervision.


Alcohol Use and Naltrexone

Naltrexone helps manage alcohol dependence by blocking opioid receptors, reducing the rewarding effects and cravings associated with alcohol. It is available in daily oral (50 mg) or monthly injectable (380 mg) forms. Naltrexone supports reduced drinking and abstinence, especially when combined with counseling and support programs. Patients taking naltrexone should not drink alcohol, as it can interfere with the medication’s effectiveness and increase the risk of side effects. Common side effects include nausea, headache, and dizziness. Regular monitoring is recommended for optimal safety and effectiveness.


Naltrexone and Pregnancy

Naltrexone’s use during pregnancy is not well-studied, and its safety is not fully established. It should be used only if the potential benefits justify the potential risks to the fetus. Pregnant women should consult their healthcare provider to carefully weigh the benefits and risks before using naltrexone. Close monitoring is recommended if it is used during pregnancy.


Naltrexone Storage and Disposal


  • Temperature: Store at room temperature, 20-25°C (68-77°F).
  • Environment: Keep in a dry place, away from light and moisture.
  • Container: Store in the original container, tightly closed.



  • Unused Medication: Follow local guidelines for disposing of unused naltrexone. Do not flush down the toilet or pour into drains.
  • Disposal Programs: Use drug take-back programs or consult your pharmacist for safe disposal methods.


Naltrexone Interaction with Medications

Naltrexone can interact with several medications, potentially altering their effects:

Opioid Medications

  • Blockage of Effect: Naltrexone blocks the effects of opioid medications, making them ineffective for pain relief or other uses.


Liver-Affecting Drugs

  • Increased Risk: Combining naltrexone with other medications that affect liver function may increase the risk of liver damage. Regular monitoring is advised.


Other CNS Depressants

  • Enhanced Side Effects: Using naltrexone with other central nervous system depressants (e.g., sedatives, alcohol) may enhance side effects like dizziness and drowsiness.


Treatment Options That Utilize Naltrexone

Inpatient Treatment with Naltrexone

  • Medical Supervision: Continuous monitoring and side effect management.
  • Structured Therapy: Intensive therapy combined with naltrexone.
  • Detoxification: Safe detox with naltrexone initiation post-detox.
  • Comprehensive Care: Includes psychological and physical health support.


Outpatient Treatment with Naltrexone

  • Flexibility: Naltrexone administered with a flexible schedule.
  • Combination Therapy: Paired with counseling and support groups.
  • Regular Monitoring: Frequent check-ups to monitor effectiveness and side effects.
  • Community Support: Access to support groups and resources.


Specific Programs

  • Intensive Outpatient Programs (IOP): Regular therapy and naltrexone administration.
  • Partial Hospitalization Programs (PHP): Day programs with medical and therapeutic support.
  • Medication-Assisted Treatment (MAT): Integration of naltrexone with other therapies.


Benefits of Naltrexone

  • Relapse Prevention: Reduces cravings and blocks euphoric effects.
  • Support for Abstinence: Helps maintain sobriety with therapy.
  • Long-Acting Formulation: Monthly injection (Vivitrol) improves adherence.


Naltrexone is effective in both inpatient and outpatient settings, aiding in recovery from opioid and alcohol dependence.


Does Insurance Cover Naltrexone Treatment?

Yes, many insurance plans cover naltrexone treatment, but coverage can vary depending on the specific insurance provider and policy. Here are some general points:

Private Insurance

  • Coverage: Most private insurance plans cover naltrexone treatment, including both oral and injectable forms.
  • Out-of-Pocket Costs: There may be co-pays, deductibles, or other out-of-pocket costs involved.
  • Pre-Authorization: Some plans may require pre-authorization before covering naltrexone.


  • Coverage: Medicaid typically covers naltrexone treatment, especially as part of medication-assisted treatment (MAT) for substance use disorders.
  • State Variation: Coverage can vary by state, so it’s important to check specific state Medicaid guidelines.


  • Coverage: Medicare Part D may cover naltrexone prescriptions. Medicare Part B might cover the injectable form (Vivitrol) if administered by a healthcare provider.
  • Out-of-Pocket Costs: There may be co-pays or coinsurance costs associated with the treatment.

Employer-Sponsored Plans

  • Coverage: Most employer-sponsored health plans cover naltrexone treatment.
  • Benefits Check: It’s important to review the specific benefits and coverage details of the employer’s health plan.

Tips for Verifying Coverage

  1. Contact Insurance Provider: Directly contact the insurance provider to verify coverage details for naltrexone.
  2. Ask Healthcare Provider: The healthcare provider or treatment facility may assist in verifying insurance coverage and handling pre-authorization.
  3. Review Policy Documents: Check the insurance policy documents for specific coverage information related to substance use treatment and medications.



Naltrexone hydrochloride represents a significant advancement in treating opioid addiction and alcohol dependence. Its ability to reduce opioid cravings and block the rewarding effects of alcohol makes it a cornerstone in modern addiction therapy. While taking naltrexone, adhering to a regular dosing schedule and being aware of potential side effects, such as joint and muscle pain or dark urine, is essential. With medical treatment, including the appropriate use of opioid antagonists like naltrexone, individuals struggling with addiction can achieve meaningful recovery. Always consult healthcare providers to ensure naltrexone is safely integrated into a complete treatment program. This medication, along with support from mental health services, can pave the way for a healthier, addiction-free life.


Seeking Treatment? We Can Help!

At New Hope Healthcare, as an in-network provider we work with most insurance plans, such as:


If you or a loved one are struggling with mental health challenges or substance abuse, reach out to New Hope Healthcare today. Our team of compassionate professionals is here to support your journey towards lasting well-being. Give us a call at 866-799-0806

Frequently Asked Questions

Naltrexone is used to treat opioid and alcohol dependence by reducing cravings and preventing relapse.
Naltrexone blocks opioid receptors in the brain, preventing the euphoric and sedative effects of opioids and reducing the rewarding effects of alcohol.
Naltrexone is available as oral tablets (50 mg) taken daily and as a monthly injectable form (Vivitrol, 380 mg).
Common side effects include nausea, headache, dizziness, fatigue, and insomnia.
Individuals currently using opioids, those with acute hepatitis or liver failure, and individuals with known hypersensitivity to naltrexone should not take it.

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