27 - Naltrexone in relapse prevention

Naltrexone in relapse prevention

Addictions and substance misuse CHAPTER 4 Opioid withdrawal in a specialist addiction in-­patient setting Methadone Patients should have a starting dose assessment of methadone over 48 hours by a ­specialist in-­patient team. The dose may then be reduced following a linear regimen over up to 4 weeks.86 Buprenorphine Buprenorphine can be used effectively for short-­term in-­patient detoxifications following the same principles as for methadone. Naltrexone in relapse prevention Trial evidence for the effectiveness of either oral or sustained-­release naltrexone as a treatment for relapse prevention in opioid misusers has been inconclusive.89,90 Naltrexone was found by NICE to be a cost-­effective treatment strategy in aiding abstinence from opioid misuse for those who prefer an abstinence programme, are fully informed of the potential adverse effects and benefits of treatment, are highly motivated to remain on treatment, and have a partner supporting concordance.91 Subsequently, Australian data indicated a threefold risk of mortality relative to methadone treatment following naltrexone cessation.92 Almost all of the excess mortality was associated with overdose deaths after stopping naltrexone. Close monitoring is particularly important when naltrexone is initiated because of the higher risk of fatal overdose at this and other times. Discontinuation of naltrexone is also associated with an increase in inadvertent overdose from illicit opioids. Postmortem data from Australia found that only 15.8% of those prescribed oral naltrexone had any naltrexone detected.93 Thus, supervision of naltrexone administration and careful choice of who is prescribed it (those who are abstinence-­focused and motivated) are very important. Although there have been concerns about people taking naltrexone experiencing adverse effects of unease (dysphoria), depression and insomnia, potentially leading to relapse to illicit opioid use or failure to continue on treatment, real-­world evidence is mixed, with two studies finding no effect of naltrexone on mood and sleep94,95 and one finding higher insomnia and distress in those patients who discontinued naltrexone.96 Initiating naltrexone Naltrexone has the propensity to cause a severe withdrawal reaction in patients who are either currently taking opioid drugs or who were previously taking opioid drugs and in whom there has not been a sufficient wash-­out period before administering naltrexone. Table 4.19  A suggested reduction regimen for buprenorphine. Daily buprenorphine dose Reduction rate Above 16mg 4mg every 1–2 weeks 8–16mg 2–4mg every 1–2 weeks 2–8mg 2mg per week or fortnight Below 2mg 0.4–0.8mg per week