The overall objective of this study is to explore the feasibility of transitioning the care of adult patients with opioid use disorder (OUD) who receive office-based buprenorphine treatment (OBBT) from physicians to pharmacists. Physicians will induce buprenorphine treatment and complete the stabilization phase before referring patients to pharmacists for the management of monthly maintenance visits. This study will assess the feasibility and acceptability of a collaborative care model between physician and pharmacist by measuring recruitment rate, treatment retention rate, treatment compliance rate, and participants' substance use. Other assessments measured will include treatment fidelity, participant, physician, and pharmacist satisfaction with OUD care, participant safety, and the pharmacists' use of electronic health records and the Prescription Drug Monitoring Program.

This study will examine the effects of oral dronabinol tetrahydrocannabinol (THC) on withdrawal symptoms in marijuana dependent volunteers, and evaluate the safety, pharmacokinetics (PK), and cardiovascular effects of the combination of oral dronabinol and smoked marijuana to determine if there are potential significant drug interactions before conducting outpatient studies. Part One is a pilot study to characterize the cardiovascular effects/safety, subjective effects, and PK of smoked marijuana and to familiarize study staff with the conduct of controlled smoking sessions.