What is the recommended use and dosage of Vivitrol (naltrexone) for opioid or alcohol dependence?

Naltrexone (Vivitrol) for Opioid and Alcohol Dependence

For alcohol dependence, Vivitrol (naltrexone) is recommended at 380 mg intramuscularly once monthly or 50 mg orally daily. For opioid dependence, patients must be completely opioid-free for 7-10 days before starting with 380 mg intramuscularly once monthly or 50 mg orally daily. 1, 2

Patient Selection and Preparation

For Alcohol Dependence

• Naltrexone is effective for maintaining abstinence in motivated patients with alcohol dependence 3, 1
• Can be started immediately without a waiting period
• Most effective when combined with psychosocial support and counseling 1

For Opioid Dependence

• Patients MUST be completely opioid-free before starting:
  • Minimum 7-10 days opioid-free interval for short-acting opioids 2
  • Longer periods (up to 2 weeks) may be needed when switching from buprenorphine or methadone 2
• Naloxone challenge test recommended if uncertain about opioid-free status 2
• Risk of precipitated withdrawal if started too early 1, 2

Dosage Regimens

Oral Naltrexone

• Alcohol dependence: 50 mg once daily 1, 3
• Opioid dependence:
  • Initial dose: 25 mg on day 1 to assess for withdrawal symptoms 2
  • Maintenance: 50 mg once daily if no withdrawal occurs 2
  • Alternative dosing: 100 mg Monday/Wednesday and 150 mg Friday 1

Injectable Naltrexone (Vivitrol)

• Both indications: 380 mg intramuscularly once every 4 weeks 4, 5
• Provides continuous blockade for one month
• Improves medication adherence compared to oral formulation 6

Monitoring and Safety

• Liver function tests should be performed:
  • At baseline
  • Every 3-6 months during treatment 1
• Common side effects include:
  • Hepatic enzyme abnormalities
  • Nasopharyngitis
  • Insomnia
  • Hypertension
  • Injection site pain 4
• Contraindicated in:
  • Current opioid use or dependence
  • Acute hepatitis or liver failure
  • Need for opioid pain management 1

Effectiveness and Outcomes

• For alcohol dependence:

  • Reduces heavy drinking days by 25% compared to placebo 5
  • More effective in men and those with lead-in abstinence 5
  • Decreases alcohol craving 3

• For opioid dependence:

  • Significantly higher opioid abstinence rates compared to placebo 4
  • Reduces opioid craving 4
  • Extends treatment retention 4

Comprehensive Treatment Approach

• Naltrexone should always be part of a comprehensive treatment plan that includes:

  • Behavioral therapies and counseling
  • Community-based support groups (e.g., Alcoholics Anonymous)
  • Regular follow-up to ensure compliance 1, 3

• For alcohol dependence, acamprosate may be considered as an alternative 3

Clinical Pearls

1. Injectable naltrexone (Vivitrol) addresses poor medication adherence issues common with oral naltrexone 6

2. For patients with both alcohol and opioid problems, very-low-dose naltrexone has shown promise in reducing withdrawal symptoms during detoxification 7

3. Patients and families should be educated about the risk of overdose if opioids are used while on naltrexone, as they may attempt to overcome the blockade with higher opioid doses 1

4. Discontinuation rates due to adverse events are higher with 380 mg injectable naltrexone (14.1%) compared to 190 mg (6.7%) and placebo (6.7%) 5