What is the recommended dosing for naltrexone (opioid receptor antagonist)?

Recommended Dosing for Naltrexone

For opioid use disorder, naltrexone should be initiated at 25 mg once daily, and if no withdrawal signs occur, increased to 50 mg once daily thereafter. 1

Dosing Regimens by Indication

Opioid Use Disorder

• Initial dose: 25 mg once daily 1
• Maintenance dose: 50 mg once daily 1
• Alternative dosing schedules:
  • 50 mg Monday and Wednesday, 100 mg Friday (total 200 mg/week) 2, 3
  • 100 mg every other day 1
  • 150 mg every third day 1

Alcohol Use Disorder

• Standard dose: 50 mg once daily 1
• Long-acting injectable formulation: 380 mg intramuscularly every 4 weeks 4

Low-Dose Naltrexone (Off-Label Uses)

• For neuropathic corneal pain: Start at 1.5 mg at bedtime with gradual bi-weekly increase of 1.5 mg to maximum 4.5 mg at bedtime 3
• For chronic pain conditions: Approximately 1/10th of standard dose (around 3-5 mg daily) 5

Monitoring and Assessment

Pre-Treatment Assessment

• Perform naloxone challenge test if there is any question of occult opioid dependence 1
  • Intravenous method: Inject 0.2 mg naloxone, observe for 30 seconds; if no withdrawal, inject 0.6 mg and observe for 20 minutes 1
  • Subcutaneous method: Administer 0.8 mg naloxone and observe for 20 minutes 1
• Ensure patient has been opioid-free for at least 7-10 days 1, 6
• Obtain baseline liver function tests 3, 2

Ongoing Monitoring

• Monitor liver function tests every 3-6 months during treatment 3, 2
• For obesity treatment: Assess treatment response at 12 weeks; discontinue if less than 5% weight loss is achieved 3, 2
• For naltrexone-bupropion combination: Discontinue if patient has not lost at least 5% of baseline body weight after 12 weeks on maintenance dose 3

Special Considerations

Contraindications

• Current opioid use or acute opioid withdrawal 1
• Patients requiring opioid analgesics 3
• Acute hepatitis or liver failure 1

Precautions

• Higher risk of hepatocellular injury with single doses above 50 mg 1
• Discontinue before procedures requiring opioid analgesia 3
• Use with caution in patients with history of seizures (when used in combination with bupropion) 3

Patient Selection Factors

• Patients most likely to benefit from naltrexone therapy are: 6
  • Employed and socially stable
  • Married
  • Stabilized on low-dose methadone prior to detoxification
  • Detoxified from opioid dependency for 7 or more days
  • Highly motivated for opioid-free treatment

Clinical Pearls

• Naltrexone does not cure dependency but assists in managing medical, psychological, and economic problems associated with substance use disorders 6
• Most effective when combined with comprehensive treatment programs including counseling and support 2
• For optimal outcomes, implement compliance-enhancing techniques for all components of treatment 1
• Alternative dosing schedules may improve adherence but could potentially reduce the degree of opioid blockade 1