Genetic background influences the change from the discriminative stimulus to the rewarding effects of psychostimulants in rats

Abstract

Aims: Antagonist therapy for opioid dependence with naltrexone, available in long-acting injectable form, represents an important but underutilized treatment option. The aims of this study are to develop procedures for outpatient detoxification and to compare induction rates onto injectable naltrexone (XR-NTX) between groups receiving naltrexone-assisted vs. buprenorphineassisted outpatient detoxification. Methods: Opioid-dependent participants seeking treatment were randomized into 2 groups for short-term outpatient opioid detoxification. One group received a 7-day buprenorphine taper, followed by a 7-day long washout and an injection of XR-NTX. A second group received a single day of buprenorphine, followed by a washout day and 4-day oral naltrexone taper and an injection of XR-NTX. Following induction, participants received behavioral therapy for 4 weeks Results: To date, 79 participants (65% white, 86% male, 34% prescription opioid users) have entered the study and were randomized to naltrexone (n=53) or buprenorphine (n=26) arm. 51% of participants in the naltrexone arm and 46% in the buprenorphine arm have been successfully inducted onto XR-NTX (p= .69). 50% of participants in the naltrexone arm and 36% in the buprenorphine arm completed Week 5 (p= .25) and received a second XR-NTX injection. Conclusions: The data from this study suggests that oral naltrexone is an important alternative medication useful in the opioid detoxification process. Participants treated with naltrexone during detoxification had comparable outcomes with those in the buprenorphine-assisted detoxification in becoming inducted onto XR-NTX. At least half of the patients undergoing oral naltrexone-assisted outpatient detoxification completed induction onto XR-NTX. These results suggest initiation of XR-NTX on an outpatient basis is a clinically viable treatment option that may be attractive to many patients and providers. Financial support: NIDA (DA 010746-09A1).