Based on the available evidence base for opioid antagonist treatment options, this guideline makes the following recommendations:
Recommendation 8. Oral naltrexone
Oral naltrexone is not a recommended treatment for adults with opioid use disorder. However, it may be offered to individuals who have declined or discontinued OAT and would prefer non-opioid treatment.
Quality of Evidence: Low
Strength of Recommendation: Weak (Conditional)
Remarks:
Available evidence suggests that oral naltrexone has limited benefit over placebo. However, it may be considered as a last resort option for patients who prefer or require non-opioid treatment options (e.g., due to employment requirements).
Patients should be informed of the risk of return to unregulated use and related harms, including drug toxicity death.
Clinicians should be informed, while naltrexone blocks the effect of opioids, it does not alleviate opioid cravings or withdrawal symptoms
Oral naltrexone may be considered in the context of an overall relapse prevention plan, after a discussion of all available options, including PRN buprenorphine/naloxone.
Recommendation 9. Extended-release Naltrexone
While extended-release naltrexone is not currently available in Canada, it is an evidence-based treatment that may be considered for patients with opioid use disorder who are not interested in OAT.
Quality of Evidence: Moderate
Strength of Recommendation: Weak(Conditional)
Remarks:
A growing body of evidence has shown extended-release naltrexone to be superior to placebo in terms of treatment retention, abstinence, and reducing cravings, and non-inferior to buprenorphine/naloxone on a variety of abstinence-related outcomes.
Extended-release naltrexone may be a suitable option when OAT medications are not appropriate due to individual circumstance (e.g., in the case of patients in safety-sensitive professions)
The guideline committee endorses the utility of this medication as a non-opioid option in the continuum of OUD care if it becomes available in Canada.
