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Clinical Differential Series

Naltrexone XR vs. Oral

A Head-to-Head Comparison for Opioid & Alcohol Use Disorders

Addiction Psychiatry Clinical Guide

Disclosure: This presentation discusses FDA-approved and off-label uses of naltrexone formulations. Content is for educational purposes only and does not constitute medical advice.

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Session Framework

Learning Objectives

📊

Compare Efficacy

Understand adherence differences between formulations
Review XR-Open trial outcomes
Identify when each formulation is appropriate

⚡

Master Initiation

Navigate the opioid-free requirement
Perform naloxone challenge correctly
Avoid precipitated withdrawal

💰

Evaluate Practical Factors

Compare costs and insurance coverage
Assess logistical requirements
Make patient-centered recommendations

🎯

Clinical Decision-Making

Apply decision trees to real cases
Recognize contraindications
Counsel patients effectively

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Clinical Context

The Adherence Problem

<30%

Oral Naltrexone

Adherent at 3 months

70-80%

XR Naltrexone

Adherent at 3 months

~3x

Difference

When successfully initiated

"The best medication is the one the patient will actually take."

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Differential

Head-to-Head Comparison

Factor	Oral (50 mg/day)	XR (380 mg/month)
Adherence at 3 months	<30%	70-80%
Efficacy for OUD	Limited (adherence failure)	Equivalent to buprenorphine*
Efficacy for AUD	Moderate (NNT ~12)	Superior (guaranteed blockade)
Cost per month	$1-5 (generic)	$1,000-1,500 (brand)
Opioid-free requirement	7-10 days	7-14 days (critical)
Override risk	Patient can simply stop	Cannot override for 30 days

*When successfully initiated — XR-Open trial, Lee et al. 2018

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Decision Framework

When to Choose Each

✓ Choose Oral Naltrexone

Alcohol use disorder in motivated patients with good adherence patterns
Cost is a barrier and insurance won't cover XR
Patient wants to "try" naltrexone before committing to injections
Low-risk alcohol use reduction (not abstinence-based)
Trial period to assess tolerability

✓ Choose XR Naltrexone

Opioid use disorder — oral essentially ineffective
Patient has failed oral naltrexone due to non-adherence
Criminal justice involvement with monitoring
Patient prefers monthly injection over daily pills
Coming from controlled environment (residential, incarceration)

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Interactive Case

Case 1 — Maria

Clinical Scenario

Patient: 34-year-old woman with alcohol use disorder
History: Multiple failed attempts at abstinence; highly motivated
Social: Stable housing, employed, strong family support
Preference: "I can take a pill every day, no problem"

Which formulation would you recommend?

Key Teaching: For AUD with good adherence patterns and motivation, oral naltrexone is a reasonable first-line option. It's cheap, easy to start, and some patients do well. XR naltrexone is preferred when adherence is a concern, but in this case, the patient has demonstrated reliability and prefers oral. Start with oral 50 mg daily; consider XR if adherence becomes an issue.

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Interactive Case

Case 2 — James

Clinical Scenario

Patient: 28-year-old man with opioid use disorder (fentanyl)
History: Two prior relapses after detox; struggles with daily medication
Current: 10 days opioid-free after residential treatment
Preference: "I don't want to be on anything long-term"

Which formulation would you recommend?

Key Teaching: For OUD, oral naltrexone is essentially ineffective due to adherence failure. XR naltrexone is the only viable naltrexone option for OUD. This patient is ideal: he's opioid-free (critical requirement), motivated for non-agonist therapy, and has a history of adherence problems. XR naltrexone provides 30 days of guaranteed blockade — a safety feature for high-risk patients.

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Critical Safety

The Initiation Problem

⚠️ The #1 Barrier to XR Naltrexone for OUD

Patients must be opioid-free for 7-14 days before first injection
In the fentanyl era, this requires managed withdrawal or residential detox
Most outpatient patients cannot achieve this without structured support
Precipitated withdrawal from naltrexone is severe and prolonged — worse than buprenorphine because naltrexone has no agonist properties

1

Confirm Opioid-Free

7-14 days minimum
UDS negative

→

2

Naloxone Challenge

0.8 mg IM
Observe 20-30 min

→

3

XR Injection

380 mg IM gluteal
Alternate sides

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Evidence

The XR-Open Trial

Lee JD et al. Comparative effectiveness of extended-release naltrexone versus buprenorphine-naloxone. Lancet 2018.

28%

XR Naltrexone

Initiation failure rate

5%

Buprenorphine

Initiation failure rate

Equivalent

Outcomes

Once successfully initiated

🎯 Bottom Line from XR-Open

XR naltrexone was harder to initiate than buprenorphine, but once initiated, outcomes were equivalent. The challenge is getting patients through the opioid-free period — not the medication itself.

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Decision Support

Formulation Selection Decision Tree

What is the primary substance use disorder?

🎯 Recommendation: XR Naltrexone (if initiation possible)

Oral naltrexone is essentially ineffective for OUD due to adherence failure
XR naltrexone = equivalent to buprenorphine when initiated
Key question: Can patient achieve 7-14 days opioid-free?
If no: Consider buprenorphine or methadone instead

🤔 Consider Both Formulations

Oral first-line: Motivated patients, good adherence history, cost concerns
XR preferred: Adherence concerns, preference for monthly dosing
Oral naltrexone actually works for AUD when taken consistently
XR guarantees 30-day blockade — no "forgetting" or skipping

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Practical Considerations

Cost & Insurance Reality

Factor	Oral Naltrexone	XR Naltrexone (Vivitrol)
Monthly cost	$1-5 (generic)	$1,000-1,500 (brand only)
Insurance coverage	Usually covered	Variable; prior auth often required
Patient assistance	Not needed	Alkermes patient assistance available
Administrative burden	Low	High (monthly visits, prior auth)
Cost-effectiveness	Excellent for AUD	Favorable for OUD when adherence is issue

💡 Practical Pearl

Don't let cost alone drive the decision for OUD. The cost of a relapse (overdose, hospitalization, lost productivity) far exceeds the cost difference. For AUD, oral naltrexone is a reasonable cost-sensitive first choice.

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Safety

Safety Considerations

⚠️ Hepatotoxicity

Black box warning on label
Clinically significant injury rare at standard doses
Obtain baseline LFTs
Monitor periodically
Contraindicated in acute hepatitis, liver failure

💉 Injection Site Reactions

Occur in 5-10% of XR injections
Pain, induration, erythema common
Rare abscess formation
Technique matters: 1.5" needle, aspirate, alternate sides
Patient counseling essential

🚨 Critical: Pain Management Blockade

For patients on chronic pain management: naltrexone blocks opioid analgesia for 30 days post-injection. Ensure alternative pain management plan (NSAIDs, acetaminophen, non-opioid adjuvants, regional anesthesia) before starting XR naltrexone.

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Clinical Wisdom

Practical Pearls

💊
For OUD, skip oral naltrexone entirely — go to XR or buprenorphine. The adherence data is unambiguous.
🎯
The biggest predictor of XR success is successful initiation. Invest in getting through the opioid-free period.
⚡
Patients transitioning from buprenorphine to naltrexone need 7-14 day washout. This is a high-risk gap — plan carefully.
📋
Always perform naloxone challenge before first XR injection. 0.8 mg IM, observe 20-30 minutes for withdrawal signs.
🍺
For AUD, oral naltrexone is a reasonable first step. It's cheap, easy to start, and some patients do well.

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Knowledge Check

Test Yourself

A patient with OUD has been opioid-free for 5 days and requests XR naltrexone. What should you do?

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Summary

Key Takeaways

1️⃣
For OUD, XR naltrexone is the only viable naltrexone formulation — oral naltrexone fails due to non-adherence.
2️⃣
XR naltrexone is equivalent to buprenorphine in outcomes when successfully initiated, but initiation is the challenge.
3️⃣
For AUD, oral naltrexone is a reasonable first-line option; XR is preferred when adherence is a concern.
4️⃣
The clinical decision comes down to: Can the patient achieve the opioid-free period, and will insurance cover XR?

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Sources

References & Further Reading

Lee JD et al. Comparative effectiveness of extended-release naltrexone versus buprenorphine-naloxone for opioid relapse prevention (XR-Open): a multicentre, open-label, randomised controlled trial. Lancet. 2018;391(10118):309-318.
Kranzler HR, Soyka M. Diagnosis and Pharmacotherapy of Alcohol Use Disorder: A Review. JAMA. 2018;320(8):815-824.
American Society of Addiction Medicine. National Practice Guideline for the Treatment of Opioid Use Disorder. 2020.
Anton RF et al. Combined pharmacotherapies and behavioral interventions for alcohol dependence: the COMBINE study. JAMA. 2006;295(17):2003-2017.
Vivitrol (naltrexone for extended-release injectable suspension) Prescribing Information. Alkermes, Inc.
Revia (naltrexone hydrochloride tablets) Prescribing Information.

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Discussion

Questions & Discussion

What questions do you have?

💬

Clinical Scenarios

Patient-specific questions

📊

Evidence

Trial data & outcomes

⚖️

Practice Integration

Workflow & logistics

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End of Presentation

Thank You

Naltrexone XR vs Oral — Clinical Differential

Additional resources available in the companion guide

📚 Speaker Companion & Enrichment Materials

Available in THE CODEX clinical guides