Surmounting Withdrawal to Initiate Fast Treatment With Naltrexone

SP includes stabilization on buprenorphine (6-8 mg) on Day 1 followed by a taper over the subsequent 4 days. After the completion of buprenorphine taper, participants will enter a washout period of at least 8 days. On the last day of the washout period, participants will be evaluated for eligibility to receive XR-NTX injection. Once found eligible, an XR-NTX injection will be given.

RP includes 1 day of buprenorphine 6-8 mg, followed by a day of washout and 4 days of oral naltrexone titration. If the participant is able to tolerate the last dose of the naltrexone titration, an XR-NTX injection will be given