Abstract
BACKGROUND AND AIM: Extended-release naltrexone (XR-NTX) blocks the effects of opioids for 4weeks; however, starting treatment can be challenging because it requires 7 to 10days of abstinence from all opioids. In the present study we identified patient and treatment characteristics that were associated with successful induction onto XR-NTX. METHODS: 144 unemployed heroin-dependent adults who had recently undergone opioid detoxification completed self-report measures and behavioral tasks before starting an outpatient XR-NTX induction procedure. Employment-based reinforcement was used to promote opioid abstinence and adherence to oral naltrexone during the induction. Participants were invited to attend a therapeutic workplace where they earned wages for completing jobs skills training. Participants who had used opioids recently were initially invited to attend the workplace for a 7-day washout period. Then those participants were required to provide opioid-negative urine samples and then take scheduled doses of oral naltrexone to work and earn wages. Participants who had not recently used opioids could begin oral naltrexone immediately. After stabilization on oral naltrexone, participants were eligible to receive XR-NTX and were randomized into one of four treatment groups, two of which were offered XR-NTX. Binary and multiple logistic regressions were used to identify characteristics at intake that were associated with successfully completing the XR-NTX induction. RESULTS: 58.3% of participants completed the XR-NTX induction. Those who could begin oral naltrexone immediately were more likely to complete the induction than those who could not (79.5% vs. 25.0%). Of 15 characteristics, 2 were independently associated with XR-NTX induction success: legal status and recent opioid detoxification type. Participants who were not on parole or probation (vs. on parole or probation) were more likely to complete the induction (OR [95% CI]=2.5 [1.1-5.7], p=0.034), as were those who had come from a longer-term detoxification program (≥21days) (vs. a shorter-term [<21days]) (OR [95% CI]=7.0 [3.0-16.6], p<0.001). CONCLUSIONS: Our analyses suggest that individuals recently leaving longer-term opioid detoxification programs are more likely to complete XR-NTX induction. Individuals on parole or probation are less likely to complete XR-NTX induction and may need additional supports or modifications to induction procedures to be successful.