How long should naltrexone (opioid receptor antagonist) be taken to minimize the risk of relapse in individuals with a history of opioid dependence?

From the Guidelines

Naltrexone should typically be taken for at least 12 months to minimize the risk of relapse in individuals with a history of opioid dependence, though some patients may benefit from longer treatment periods of several years. The standard oral dose is 50mg daily, while the extended-release injectable form (Vivitrol) is administered as a 380mg intramuscular injection once monthly 1. Before starting naltrexone, patients must be fully detoxified from opioids (7-10 days opioid-free) to avoid precipitating withdrawal. Treatment should be part of a comprehensive approach that includes counseling and psychosocial support. Naltrexone works by blocking opioid receptors, preventing the euphoric and sedative effects of opioids if they are used. This mechanism helps reduce cravings and prevents reinforcement of drug-seeking behavior. The medication is non-addictive and does not cause physical dependence. Discontinuation should be gradual and decided collaboratively between the patient and healthcare provider based on stability in recovery, strong support systems, and developed coping strategies. Regular monitoring for side effects like nausea, headache, and liver function changes is important throughout treatment.

Some key points to consider when prescribing naltrexone include:

• The patient's motivation to quit opioid use
• The presence of support systems, such as counseling and psychosocial support
• The patient's medical history, including any liver disease or other health conditions that may affect the use of naltrexone
• The potential for naltrexone to precipitate withdrawal in patients who are not fully detoxified from opioids. According to recent guidelines, clinicians should offer or arrange evidence-based treatment (usually medication-assisted treatment with buprenorphine or methadone in combination with behavioral therapies) for patients with opioid use disorder 1. However, naltrexone can be a useful alternative for highly motivated patients.

It's also important to note that naltrexone has been associated with hepatic injury at supratherapeutic doses, and liver function tests should be performed at baseline and every three to six months 1. Overall, naltrexone can be a valuable tool in the treatment of opioid dependence, but it should be used as part of a comprehensive treatment plan that includes counseling, psychosocial support, and regular monitoring for side effects.

From the Research

Duration of Naltrexone Treatment

To minimize the risk of relapse in individuals with a history of opioid dependence, the duration of naltrexone treatment is crucial. The following points highlight the key findings:

• A study published in 2007 2 found that patients with blocked use (i.e., those who took naltrexone as prescribed) had a lower dropout rate (33% retained at 6 months) compared to those with unblocked use (10% retained at 6 months).
• Another study from 2007 3 suggested that naltrexone may be beneficial in helping formerly opioid-dependent individuals remain abstinent, although the quality of the evidence is relatively poor and heterogeneous.
• A 1997 study 4 investigated compliance with a 9-month course of naltrexone and found that non-relapse patients took naltrexone for an average of 2 months longer than relapse patients.
• The study also found that about half of the non-relapse patients completed at least 5 months of naltrexone, 30% completed at least 7 months, and about 20% completed 9 months.
• A 2021 study 5 explored the use of extended-release naltrexone for longer-term abstinence in opioid-dependent individuals and found that pharmacological treatment should include psychosocial interventions to improve longer-term recovery.
• A 2011 study 6 discussed the use of long-acting injectable naltrexone for the management of patients with opioid dependence and found that treatment with long-acting naltrexone should be monitored for hepatotoxicity and patients should be made aware of the increased risk of overdose with administration of opioids during and immediately after discontinuation of long-acting naltrexone.

Key Considerations

When considering the duration of naltrexone treatment, the following points are essential:

• The treatment should be individualized, and the duration of naltrexone treatment may vary depending on the patient's response and needs.
• Psychosocial interventions should be included in the treatment plan to improve longer-term recovery.
• Patients should be monitored for hepatotoxicity and made aware of the increased risk of overdose with administration of opioids during and immediately after discontinuation of long-acting naltrexone.
• The use of extended-release naltrexone may be beneficial for longer-term abstinence in opioid-dependent individuals.