What are the recommended steps to initiate Vivitrol (naltrexone) for a patient?

How to Initiate Vivitrol (Naltrexone IM)

Patients must be completely opioid-free for a minimum of 7-10 days before initiating Vivitrol to prevent life-threatening precipitated withdrawal. 1, 2

Pre-Initiation Requirements

Mandatory Opioid-Free Period

• Short-acting opioids (heroin, oxycodone, hydrocodone): Minimum 7-10 days opioid-free before starting Vivitrol 1, 2
• Buprenorphine/Sublocade: Extended waiting period of weeks to months required due to prolonged half-life (43-60 days for Sublocade) 1, 3
• Methadone: Patients may be vulnerable to precipitated withdrawal for as long as 2 weeks after discontinuation 2

Verify Opioid-Free Status

• Urine drug screen: Must be negative for opioids before initiating Vivitrol 2
• Naloxone challenge test: Strongly recommended if any question of occult opioid dependence exists 2
  • IV route: Inject 0.2 mg naloxone, observe 30 seconds; if no withdrawal, inject 0.6 mg and observe 20 minutes 2
  • Subcutaneous route: Administer 0.8 mg naloxone, observe 20 minutes 2
  • Positive test (withdrawal signs appear): Do NOT initiate Vivitrol; repeat challenge in 24 hours 2
  • Negative test: May proceed with Vivitrol if no other contraindications 2

Screen for Absolute Contraindications

• Current opioid use or physiological dependence: Absolute contraindication 1, 4
• Acute hepatitis or liver failure: Absolute contraindication 1
• Patients requiring opioid analgesics (short-term or long-term): Should not receive Vivitrol 1, 4
• Clinical signs of opioid withdrawal: Do not perform naloxone challenge or initiate Vivitrol 2

Dosing Protocol

Initial Dosing for Opioid Dependence

• Start with oral naltrexone 25 mg test dose: If no withdrawal signs occur, may proceed to full dose 2
• Vivitrol IM injection: 380 mg intramuscularly once every 4 weeks 5
• Must be combined with psychosocial support: Vivitrol is only effective as part of comprehensive addiction treatment program 2, 6

Critical Safety Warnings

Precipitated Withdrawal Risk

• Mechanism: Vivitrol displaces any residual opioids from mu-receptors, causing severe withdrawal 1, 3
• Severe symptoms include: Vomiting, diarrhea, cardiovascular arrhythmias, seizures, pulmonary edema, cardiac arrest in extreme cases 1, 4
• Most critical error: Initiating without confirmed opioid-free period leads to precipitated withdrawal 1
• Patients transitioning from buprenorphine/methadone: May require hospitalization if withdrawal is precipitated 2

Hepatotoxicity Monitoring

• Baseline liver function tests: Required before initiation 1
• Ongoing monitoring: Liver function tests every 3-6 months due to hepatotoxicity risk 1
• Patient education: Instruct patients to immediately notify physician if signs/symptoms of liver disease develop 2

Patient Education Requirements

Before Starting Vivitrol

• Inform patients: They must be off all opioids, including opioid-containing medicines, for minimum 7-10 days 2
• Warn about increased overdose risk: Patients previously using opioids may be more sensitive to lower doses after Vivitrol discontinuation 2
• Explain opioid blockade: Large doses of opioids to bypass blockade may lead to serious injury, coma, or death 2
• Pain management limitations: Patients will not benefit from opioid-containing analgesics, antidiarrheals, or antitussives while on Vivitrol 2

Provide Identification Card

• Naltrexone medication card: Patients should carry identification alerting medical personnel they are taking Vivitrol 2
• Emergency situations: Ensures adequate treatment if emergency medical care is needed 2

Perioperative Considerations

Planned Procedures Requiring Opioids

• Oral naltrexone: Hold 3-4 days before elective procedures 1, 4
• Vivitrol IM: Hold 24-30 days after last injection before elective procedures 1, 4
• Emergency surgery: May require regional anesthesia or non-opioid analgesics; higher opioid doses may be needed to overcome blockade 2

Common Pitfalls to Avoid

• Never initiate without confirmed opioid-free period: This is the most critical error leading to precipitated withdrawal 1
• Do not use in patients who may need opioid analgesics: Naltrexone blocks opioid efficacy for pain management 1, 4
• Do not rely solely on patient self-report: Use urine drug screening and consider naloxone challenge test 2
• Do not forget psychosocial support: Medication alone is insufficient; comprehensive treatment program is essential 2, 6
• Do not overlook liver function monitoring: Hepatotoxicity is a significant risk requiring regular monitoring 1