Evaluation of Doxazosin to Alter the Abuse of Oxycodone

Healthy, adult men and women, aged 21 to 59 years, who abuse opioids and are physically dependent on them will be recruited to participate in a study to examine the ability of doxazosin, an epinephrine receptor blocker, to alter the abuse potential of oxycodone. After participants complete the screening process, they will be scheduled for inpatient admission onto our clinical inpatient where they will reside during the 8-week study. During Weeks 1-2, participants will be transitioned from their normal opioid use regime onto oral morphine until withdrawal dissipates. At this time participants will also be stabilized on the first dose of doxazosin (0 or 16 mg/day; active doxazosin will be started at 4 mg and increased by 4 mg every 3 days). During Weeks 3-4, either active or placebo oxycodone will be available (in random order). Monday-Friday each these drugs will be tested using our sample and choice self-administration procedure. On Friday, participants will also complete a cue exposure session during which they will be presented drug cues to determine whether the study medication affects how participants react to them. To summarize, Weeks 1-2 and 5-6 will be stabilization weeks (0 or 16 mg doses of doxazosin administered in random order) and Weeks 3-4 and 7-8 will be test weeks under each of the doxazosin maintenance doses. At the conclusion of the study, participants will be given an exit interview, warnings about re-initiation of opioid use, and counseling about the different treatment options for Opioid Use Disorder. Within 1 week after discharge, investigators will assess adverse events using the a number of clinical assessments. At each weekly visits, investigators will assess participants' interest in treatment and drug use patterns.