A week-long outpatient induction onto XR-naltrexone in patients with opioid use disorder

Extended-release (XR) naltrexone can prevent relapse to opioid use disorder following detoxification. However, one of the barriers to initiating XR-naltrexone is the recommendation for a 7-10-day period of abstinence from opioids prior to the first dose.

The current study evaluated the feasibility of an XR-naltrexone induction protocol that can be implemented over 1 week in the outpatient clinic.

Participants (N = 44) were seen in the clinic daily. On Day 1, after abstaining from opioids for at least 12 h, they received buprenorphine 6-8 mg. Adjunctive medications (clonidine, clonazepam, zolpidem, trazodone, and prochlorperazine) were dispensed on Days 2-5, while ascending oral doses of naltrexone were given on Days 3-5 starting with 1 mg dose. An injection of XR-naltrexone was given on Day 5, 1 h after receiving and tolerating naltrexone 24 mg.

Of the 44 participants (38 males), 35 (80%) were heroin users and 9 (20%) used prescription opioids. A total of 26 participants (59%) completed the induction and received their first injection of XR-naltrexone. XR-naltrexone was initiated in 54% (19/35) of heroin users and 78% (7/9) of prescription opioid users.

The results support the feasibility of a week-long outpatient induction onto XR-naltrexone with ascending doses of naltrexone and standing doses of adjunctive medications. By circumventing the need for a protracted period of abstinence and mitigating the severity of withdrawal symptoms experienced during naltrexone titration, this strategy has the potential to increase patient acceptability and access to relapse prevention treatment with XR-naltrexone.