Naltrexone for Opioid Use Disorder: How It Works and Who It Helps

Opioid use disorder affects millions of people across the United States, creating a complex health challenge that requires evidence-based treatment approaches.

At Fusion Recovery Center, we understand that recovery involves more than willpower. It requires comprehensive medical support and proven medications that address the brain changes caused by addiction.

Naltrexone is an FDA-approved medication that blocks opioid receptors in the brain, preventing the euphoric effects of opioids and reducing cravings to help people maintain their recovery.

Unlike other addiction medications, naltrexone has no abuse potential and doesn’t cause physical dependence. This makes it a unique tool in opioid use disorder treatment.

Throughout this article, we’ll explore how naltrexone works in the brain and who benefits most from this treatment.

We’ll also discuss the different forms available, potential side effects, and why combining naltrexone with counseling and behavioral therapies creates the strongest foundation for long-term recovery success.

Key Takeaways

• Naltrexone blocks opioid receptors in the brain to prevent euphoric effects and reduce cravings without causing dependence.
• The medication works best for people who have completed detox and are committed to comprehensive treatment programs.
• Combining naltrexone with counseling and behavioral therapies provides the most effective approach to long-term recovery.

Understanding Opioid Use Disorder and the Role of Naltrexone

Opioid dependence creates lasting changes in brain chemistry that make recovery challenging without proper medical support.

Medication-assisted treatment offers evidence-based approaches that address both the physical and psychological aspects of opioid addiction.

How Opioid Dependence Develops

Physical dependence forms when the brain adapts to regular opioid use.

The body starts needing opioids just to feel normal.

At first, people use opioids for pain relief or euphoric effects.

Over time, the brain requires higher doses to achieve the same results. This process is called tolerance.

Withdrawal symptoms appear when opioid levels drop. These include:

• Muscle aches and pains
• Nausea and vomiting
• Anxiety and irritability
• Sleep problems

The fear of withdrawal often drives continued use.

We see this cycle trap many people in opioid dependence, even when they want to stop.

Opioid use disorder develops when use causes significant problems in daily life.

This includes work issues, relationship problems, or health complications.

The Science of Addiction and Brain Chemistry

Opioids attach to mu-opioid receptors in the brain.

These receptors control pain, pleasure, and breathing functions.

When opioids bind to these receptors, they release large amounts of dopamine.

This creates intense feelings of pleasure and relief. The brain remembers this reward and craves more.

Long-term opioid use changes how the brain works.

The natural reward system becomes damaged. Normal activities no longer provide satisfaction.

These brain changes explain why addiction recovery requires more than willpower.

The altered brain chemistry makes it extremely difficult to stop using opioids without medical help.

Research shows these changes can last months or years after stopping opioid use.

This is why medication-assisted treatment plays such an important role in recovery.

Medication-Assisted Treatment Approaches

MAT combines medications with counseling and behavioral therapies.

This approach treats opioid addiction as a medical condition rather than a moral failing.

Three FDA-approved medications treat opioid use disorder:

Naltrexone works differently from the other two options.

It blocks opioid effects completely instead of replacing them.

This medication prevents the euphoric feelings that opioids normally create.

If someone tries to use opioids while on naltrexone, they won’t feel the desired effects.

Medication-assisted treatment has proven most effective for long-term recovery.

Studies show people stay in treatment longer and have better outcomes compared to counseling alone.

The choice of medication depends on individual circumstances, medical history, and treatment goals.

How Naltrexone Works for Opioid Use Disorder

Naltrexone functions as an opioid receptor antagonist that blocks the brain’s reward pathways and eliminates the euphoric effects of opioids.

We use this medication to help patients break the cycle of addiction by reducing cravings and creating a protective barrier against relapse.

Opioid Receptor Antagonism and Brain Pathways

Naltrexone works by binding to opioid receptors in the brain, particularly the mu-opioid receptors.

These receptors normally respond to natural endorphins and opioid drugs.

When we prescribe naltrexone, it acts as an opioid receptor antagonist.

This means it blocks these receptors without activating them.

The medication has a strong attraction to mu-opioid receptors.

It stays attached for 24 hours or longer with oral doses.

Key receptor interactions include:

• Blocking mu-opioid receptors in the brain’s reward center
• Preventing activation of dopamine pathways
• Interrupting the brain’s natural reward system

This blocking action stops the normal chain reaction that leads to feelings of pleasure from opioid use.

The brain cannot process the rewarding effects that typically reinforce drug-seeking behavior.

Blocking the Effects of Opioids

Naltrexone creates a complete blockade against opioid effects.

When patients take opioids while on naltrexone, they experience no euphoria or pain relief.

This blocking effect works with all types of opioids:

• Heroin
• Prescription painkillers like oxycodone
• Morphine
• Fentanyl

The medication prevents dopamine release in the brain’s reward pathways.

Without this dopamine surge, patients feel no satisfaction from opioid use.

Important timing considerations:

• Patients must be fully detoxed before starting naltrexone
• Taking naltrexone with opioids still in the system causes severe withdrawal
• The blocking effect lasts 24-72 hours depending on the dose

We often recommend the monthly injection form (Vivitrol) for better medication adherence.

Reducing Cravings and Preventing Relapse

Naltrexone helps reduce cravings by breaking the connection between triggers and reward expectations.

When patients know opioids won’t work, psychological cravings often decrease over time.

The medication serves as a powerful tool for relapse prevention.

Even if patients have moments of weakness, naltrexone provides a safety net.

Benefits for craving reduction:

• Weakens conditioned responses to drug cues
• Reduces obsessive thoughts about using
• Helps patients feel more in control

Studies show patients on naltrexone have 50% fewer positive drug tests compared to those without medication.

The medication works best when patients are motivated to stay sober.

It doesn’t eliminate all cravings but makes them much more manageable during early recovery.

Naltrexone Forms and Administration Options

Naltrexone comes in two main forms: oral tablets taken daily and extended-release injections given monthly.

Each option offers different benefits for adherence and convenience.

Oral Naltrexone Tablets (ReVia)

Oral naltrexone is available as a daily tablet, most commonly in 50 mg doses.

The brand name ReVia is widely recognized, though generic versions are available at lower costs.

Daily Administration Schedule:

• Standard dose: 50 mg once daily
• Test dose: 25 mg initially to check tolerance
• Alternative schedules: 100 mg every other day or 150 mg every third day

The oral tablet can be taken with or without food.

Taking it with food may help reduce nausea, which is the most common side effect.

Patients must be opioid-free for 7-10 days before starting treatment.

We recommend verifying this through urine drug screening to prevent withdrawal symptoms.

Key Benefits:

• Lower cost than injectable form
• Flexible dosing options
• Easy to adjust or stop if needed

Main Challenges:

• Requires daily adherence
• Higher risk of missed doses
• May cause more stomach upset initially

Extended-Release Injectable Naltrexone (Vivitrol)

Vivitrol is an extended-release injection given once monthly by a healthcare provider.

Each injection contains 380 mg of naltrexone that releases slowly over four weeks.

The injection is given deep into the muscle of the buttocks.

It must be administered by trained medical staff in a clinical setting.

Administration Details:

• Frequency: Once every 28-30 days
• Location: Intramuscular injection in gluteal muscle
• Setting: Must be given in healthcare facility

Preparation Requirements:

• Patient must be opioid-free for 7-10 days
• Complete medical evaluation before first injection
• Injection site monitoring for reactions

Major Advantages:

• Eliminates daily dosing concerns
• Ensures consistent medication levels
• Reduces risk of treatment gaps

Potential Drawbacks:

• Higher cost than oral form
• Requires monthly clinic visits
• Cannot be stopped immediately if problems occur

Comparing Oral vs. Injectable Naltrexone

Both forms work equally well for blocking opioids when taken consistently.

The choice depends on patient needs, lifestyle, and ability to maintain treatment schedules.

Best Candidates for Oral Form:

• Patients with reliable daily routines
• Those wanting lower treatment costs
• Individuals preferring medication flexibility

Best Candidates for Injectable Form:

• Patients with adherence challenges
• Those wanting monthly convenience
• Individuals with strong healthcare support systems

The injectable form may be preferred for patients who have struggled with taking daily medications consistently.

However, oral naltrexone works well for motivated patients who can maintain daily schedules.

Who Benefits Most from Naltrexone Treatment

Naltrexone works best for specific groups of people with opioid use disorder.

Success depends on liver health, commitment to complete opioid detox, and individual medical factors.

Ideal Candidates for Naltrexone

The best candidates for naltrexone have completed full opioid detoxification.

We see the highest success rates in people who have been opioid-free for at least 7-10 days.

Motivated individuals who want to maintain abstinence do well with naltrexone.

The medication works by blocking opioid effects rather than replacing them.

People with strong support systems often succeed with naltrexone treatment.

Family involvement and counseling help patients stay committed to the medication schedule.

Good candidates include:

• Those completing residential treatment programs
• Individuals with stable housing and employment
• People involved in ongoing therapy or support groups
• Those who prefer non-opioid medications

Healthcare workers and professionals in recovery often choose naltrexone.

The medication allows them to work without concerns about controlled substances.

Contraindications and Cautions

We cannot prescribe naltrexone to people with active liver disease.

The medication can cause hepatotoxicity in some patients.

Liver function tests are required before starting treatment.

We monitor these tests regularly during naltrexone therapy to watch for liver damage.

People still using opioids cannot start naltrexone safely.

The medication will cause severe withdrawal symptoms called precipitated withdrawal.

Major contraindications include:

• Active hepatitis or liver failure
• Current opioid use or dependence on opioid pain medications
• Severe kidney disease
• Pregnancy (safety not established)

Patients taking opioid pain medications must stop these drugs first.

We work with their doctors to find alternative pain management options.

Considerations for Special Populations

Pregnant women should avoid naltrexone unless benefits clearly outweigh risks. Other treatment options are recommended during pregnancy and breastfeeding.

Older adults need careful monitoring for liver problems. Age-related changes in liver function can increase the risk of hepatotoxicity.

People with chronic pain face special challenges with naltrexone. The medication blocks all opioid medications, including prescription pain relievers.

We discuss stopping naltrexone plans with all patients. Medical emergencies requiring opioid pain medication need special protocols.

Young adults often struggle with naltrexone compliance. Monthly injection forms may work better than daily pills for this group.

Patients with mental health conditions need coordinated care. Depression and anxiety can affect treatment success and medication adherence.

Comparing Naltrexone with Other Medications for Opioid Use Disorder

Three FDA-approved medications treat opioid use disorder: naltrexone blocks opioid effects, methadone provides full opioid activation, and buprenorphine offers partial opioid activation. Each medication works differently and suits different patient needs and circumstances.

Naltrexone vs. Methadone

Naltrexone and methadone work in opposite ways. Naltrexone blocks opioid receptors completely, preventing any opioid effects.

Methadone (brand name Dolophine) is a full opioid agonist that activates the same receptors that other opioids target.

Key differences include:

• Mechanism: Naltrexone prevents opioid effects; methadone provides controlled opioid effects
• Physical dependence: Naltrexone doesn’t cause dependence; methadone does create dependence
• Withdrawal: Stopping naltrexone causes no withdrawal; stopping methadone requires careful tapering

Methadone requires daily visits to special clinics called opioid treatment programs. Patients must be physically dependent on opioids to start methadone safely.

Naltrexone requires complete detox first. Patients must be opioid-free for 7-10 days before starting naltrexone to avoid severe withdrawal.

Research shows methadone keeps patients in treatment longer than naltrexone.

Naltrexone vs. Buprenorphine

Buprenorphine is a partial opioid agonist that partially activates opioid receptors. This creates a “ceiling effect” that limits respiratory depression risk.

Suboxone combines buprenorphine with naloxone to prevent misuse.

Treatment access differs significantly:

• Location: Buprenorphine can be prescribed in regular doctor offices; naltrexone has even fewer restrictions
• Prescriber requirements: Buprenorphine needs special waivers; naltrexone doesn’t require special training
• Flexibility: Both allow take-home dosing, unlike methadone’s daily clinic visits

Studies comparing these medications show mixed results. One large study found buprenorphine had lower return-to-use rates than naltrexone, mainly because starting naltrexone proved more difficult.

When patients successfully started either medication, both worked similarly well. The key difference is that buprenorphine can be started while still using opioids, but naltrexone requires complete abstinence first.

Key Differences and Selection Criteria

Several factors are considered when choosing between these medications.

Patient readiness and circumstances:

• Current opioid use (buprenorphine or methadone for active use; naltrexone for abstinent patients)
• Motivation level (naltrexone requires high motivation)
• Support system strength

Medical factors:

• Pregnancy status (methadone or buprenorphine recommended; naltrexone not advised)
• Other substance use (naltrexone also treats alcohol use disorder)
• Safety-sensitive jobs (naltrexone preferred for some occupations)

Treatment history and preferences:

• Previous medication responses
• Patient preference for agonist vs. antagonist treatment
• Side effect tolerance

No single medication works best for everyone.

Comprehensive Recovery: Naltrexone, Counseling, and Behavioral Therapies

Naltrexone works best when combined with counseling and behavioral interventions to address both the physical and mental aspects of addiction. We create personalized treatment plans that include medication, therapy, and ongoing support to help our patients build lasting recovery skills.

Integrating Medication with Psychosocial Interventions

We combine naltrexone with proven behavioral therapies to give our patients the best chance at recovery. Medication helps reduce cravings and blocks opioid effects.

Counseling teaches coping skills and addresses the mental side of addiction.

Our integrated approach includes:

• Individual therapy sessions with licensed counselors
• Group therapy to connect with others in recovery
• Family counseling to repair relationships
• Cognitive behavioral therapy to change harmful thought patterns

We schedule therapy sessions regularly while patients take naltrexone. This timing helps reinforce the medication’s benefits.

When cravings decrease from naltrexone, patients can focus better during counseling sessions.

Studies show that patients who receive both medication and therapy stay in treatment longer. They also have lower relapse rates compared to those who only use medication.

Personalized Treatment Planning at Fusion Recovery Center

We assess each patient’s unique needs before creating their treatment plan. Our team looks at addiction history, mental health conditions, family support, and personal goals.

This helps us design the right mix of naltrexone and behavioral interventions.

Our assessment process covers:

• Medical history and current health status
• Previous addiction treatment attempts
• Co-occurring mental health disorders
• Social support systems and living situations

We adjust treatment plans as patients progress through recovery. Some patients need more intensive counseling at first.

Others benefit from longer naltrexone treatment periods.

Our team meets weekly to review each patient’s progress. We modify plans based on how well patients respond to different behavioral therapies.

This flexible approach helps us address challenges quickly and keep patients on track.

Relapse Prevention Strategies and Ongoing Support

We teach specific relapse prevention strategies that work alongside naltrexone treatment. These skills help patients handle triggers and high-risk situations.

Our behavioral interventions focus on real-world challenges patients will face.

Key relapse prevention tools include:

• Identifying personal triggers and warning signs
• Developing healthy coping strategies for stress
• Building strong support networks
• Creating structured daily routines

We provide ongoing support even after patients complete our main program. Our alumni groups meet monthly to maintain connections.

We also offer refresher counseling sessions when patients need extra help.

Our 24-hour crisis support line gives patients immediate help during difficult moments. This safety net works with naltrexone to prevent relapse during vulnerable times.

We track long-term outcomes to ensure our comprehensive approach continues working for each patient.

Side Effects and Safety of Naltrexone

Naltrexone can cause mild to serious side effects that vary from person to person. Most side effects are manageable with proper care, but some require immediate medical attention.

Common Side Effects and Management

The most frequent side effects of naltrexone include nausea, headache, dizziness, and fatigue. These symptoms usually happen during the first few weeks of treatment.

Nausea affects many patients starting naltrexone. We recommend taking the medication with food to reduce stomach upset.

Small, frequent meals can also help.

Headache and dizziness are common early side effects. Staying well-hydrated and avoiding sudden position changes can minimize these symptoms.

Most headaches improve after the first month.

Other common side effects include:

• Loss of appetite
• Sleep problems (insomnia)
• Mild anxiety
• Joint or muscle pain
• Stomach cramps

Sleep issues may occur, especially insomnia. Taking naltrexone earlier in the day can help reduce nighttime sleep problems.

Most common side effects are temporary. They often get better as your body adjusts to the medication over 2-4 weeks.

If side effects persist or worsen, contact your healthcare provider. Never stop taking naltrexone suddenly without medical guidance.

Serious Adverse Effects and When to Seek Help

Some side effects of naltrexone require immediate medical attention. Liver damage is the most serious concern with naltrexone use.

Signs of liver problems include:

• Yellow skin or eyes (jaundice)
• Dark urine
• Severe stomach pain
• Unusual tiredness
• Loss of appetite with nausea

We monitor liver function with regular blood tests during treatment. People with existing liver disease should not take naltrexone.

Severe allergic reactions are rare but dangerous. Seek emergency care for:

• Difficulty breathing
• Swelling of face, lips, or throat
• Severe skin rash
• Rapid heartbeat

Mental health changes can occur, including worsening depression or anxiety. Some people may have thoughts of self-harm.

Contact your doctor immediately if you experience mood changes, increased anxiety, or depression while taking naltrexone.

Call 911 or go to the emergency room for any life-threatening symptoms or thoughts of suicide.

Naltrexone for Alcohol Use Disorder and Dual Diagnosis Cases

Naltrexone blocks opioid receptors in the brain that help create alcohol’s rewarding effects, making it effective for both alcohol addiction and opioid dependence. We often use this medication when patients have both conditions, though treatment timing and alternatives require careful consideration.

How Naltrexone Reduces Alcohol Cravings

Naltrexone works by blocking the body’s opioid receptor system. When people drink alcohol, their brains release natural opioids that create pleasurable feelings.

The blocking process prevents this reward cycle. Without the euphoric effects, alcohol becomes less appealing.

This reduction in reward makes it easier for patients to resist drinking.

Research shows naltrexone reduces heavy drinking episodes significantly. We see patients experience fewer cravings and drink less overall when they do consume alcohol.

Gender differences affect treatment response. Women often respond better to stress-related triggers, while men show stronger responses to alcohol-related cues.

We consider these patterns when developing treatment plans.

The medication comes in both daily pills and monthly injections. Injectable naltrexone often works better because patients don’t need to remember daily doses during recovery.

Alternatives for Alcohol Dependence

We have several FDA-approved medications for alcohol use disorder beyond naltrexone.

Primary Options:

• Acamprosate – Reduces withdrawal symptoms and cravings
• Disulfiram – Creates unpleasant reactions when alcohol is consumed

Off-label medications we sometimes prescribe include:

• Topiramate – An anti-seizure drug that reduces drinking
• Gabapentin – Helps with anxiety and sleep issues during recovery

Each medication targets different aspects of alcohol addiction.

Acamprosate works best for patients who have stopped drinking completely. Disulfiram requires strong motivation because it makes people very sick if they drink.

Dual Diagnosis Treatment Considerations

Patients with both alcohol use disorder and opioid dependence need special care.

We prefer treating both conditions with naltrexone when possible because it addresses both addictions.

Timing is critical. Patients must be completely off opioids for 7-14 days before starting naltrexone.

Starting too early can trigger severe withdrawal symptoms.

Rapid initiation programs show better success rates. We can sometimes start treatment in 5-7 days with close medical supervision instead of waiting two weeks.

Women with dual diagnosis often have higher rates of trauma and chronic pain.

We address these co-occurring conditions alongside addiction treatment.

Medical supervision is essential during the transition period.

Patients face high risks of relapse or overdose while waiting to start naltrexone treatment.

Conclusion: Naltrexone Offers a Path Forward—But Timing and Support Are Critical

Naltrexone is a powerful tool in the fight against opioid addiction, offering a non-addictive, non-opioid-based method to block the euphoric effects of opioids and reduce cravings. Its success depends on starting treatment after full detoxification and combining it with comprehensive behavioral support. While not appropriate for everyone—particularly those who haven’t completed detox or have liver issues—naltrexone plays a vital role for individuals committed to abstinence and long-term recovery. The key is a personalized treatment plan that includes medical oversight, counseling, and a stable support network to sustain progress and prevent relapse.

Fusion Recovery specializes in individualized care that pairs naltrexone with therapy, education, and structured support to empower lasting change. Schedule your confidential consultation today and take the next step toward your recovery with a trusted team by your side.