Summary: This study investigates the effects of Tizanidine on the voluntary movement controls of the arms of participants who have had a stroke and have not had a stroke by measuring medication-induced changes in upper extremity kinematics, pupillometry, and brain activity. Tizanidine is approved by the U.S. Food and Drug Administration. Understanding how different areas of the brain are involved in moveme...

Summary: The main goal of this clinical study is to test how CYP2B6 genetic variations and efavirenz (cornerstone in HIV-1 therapy) dictate the disposition (PK) of CYP2B6 substrate (methadone) and PK and effect (PD) of CYP1A2 substrate (tizanidine). Specifically, the investigators will test whether efavirenz produces CYP2B6 genotype dependent unanticipated DDIs with CYP2B6 (methadone) and CYP1A2 (tizanidin...

Summary: The goal of this clinical trial is to learn whether a combined behavioral and pharmacologic intervention can help reduce opioid use, improve pain recovery, and prevent opioid misuse after surgery in adults undergoing elective surgery. The study includes adults aged 18 to 75 who have a history of long-term opioid use, defined as having access to opioids for 60 or more days within the 180 days befor...