What are the guidelines for prescribing Vivitrol (naltrexone)?

Guidelines for Prescribing Vivitrol (Naltrexone)

Intramuscular naltrexone (Vivitrol) should be held 24-30 days after the last injection before surgery, and patients must be completely opioid-free for 7-10 days before initiating treatment to prevent precipitated withdrawal. 1, 2

Patient Selection and Pre-Treatment Assessment

• Vivitrol is indicated for:

  • Prevention of relapse to opioid dependence following opioid detoxification
  • Treatment of alcohol dependence

• Before initiating treatment:

  1. Confirm patient is completely opioid-free for 7-10 days (including tramadol) 2
  2. Perform naloxone challenge test if there's any question of occult opioid dependence:
     • Intravenous method: Inject 0.2 mg naloxone, observe for 30 seconds; if no withdrawal, inject 0.6 mg and observe for 20 minutes
     • Subcutaneous method: Administer 0.8 mg naloxone, observe for 20 minutes
     • If signs of withdrawal appear, do NOT start Vivitrol; repeat challenge in 24 hours 2

Dosing Protocol

• Standard dose: 380 mg intramuscular injection every 4 weeks 3
• Administration site: Gluteal muscle using the provided needle
• Alternate dosing for oral naltrexone (not Vivitrol): 50 mg daily, or 100 mg every other day, or 150 mg every third day 2

Monitoring and Follow-Up

• Monitor for injection site reactions
• Assess for hepatic enzyme abnormalities at baseline and periodically during treatment 3
• Evaluate treatment response by:
  • Opioid abstinence (self-report and urine testing)
  • Reduced cravings
  • Improved psychosocial functioning 4
• Continue treatment for at least 6 months for optimal outcomes 4

Important Precautions

1. Risk of precipitated withdrawal: Ensure complete opioid detoxification before initiating treatment 2, 5

2. Risk of opioid overdose:

   • Warn patients about increased sensitivity to opioids near the end of the dosing interval
   • Risk of overdose if attempting to overcome the blockade with high doses of opioids 5
   • Patients who discontinue Vivitrol are at increased risk of overdose due to decreased tolerance 1

3. Surgery and pain management:

   • Hold Vivitrol 24-30 days before scheduled surgery 1
   • Patients on Vivitrol cannot receive opioid pain medications
   • Coordinate with anesthesiologists if naltrexone was administered within 4 hours preoperatively 1

4. Hepatic concerns:

   • Monitor liver function tests
   • Use caution in patients with liver disease 3

Contraindications

• Current opioid dependence or use
• Acute opioid withdrawal
• Failed naloxone challenge test
• Hypersensitivity to naltrexone
• Acute hepatitis or liver failure

Common Side Effects

• Injection site reactions
• Hepatic enzyme abnormalities
• Nasopharyngitis
• Insomnia
• Hypertension
• Influenza-like symptoms 3

Treatment Outcomes and Expectations

• Patients receiving 6 or more injections show better outcomes in:
  • Employment
  • Mental health
  • Psychosocial functioning
  • Decreased opioid craving and drug use 4
• Extended-release naltrexone has shown significantly longer time to relapse compared to usual treatment (10.5 vs 5.0 weeks) 6
• Treatment effects may wane after discontinuation 6

Clinical Pearls

• Patients with better baseline mental health, higher education, and lower recent drug use tend to remain in treatment longer 4
• The opioid blockade may be overcome when naltrexone levels drop toward the end of the dosing interval, creating vulnerability to subsequent naltrexone-induced withdrawal if the patient uses opioids and then receives their next dose 5
• Testing the blockade (using opioids while on naltrexone) can lead to extinction of drug-seeking behavior at adequate doses, but may lead to dropout at inadequate doses 7