RecruitingPhase 1Drug trialStudy to Assess the Use of Tezampanel for Opioid Withdrawal Syndrome in Treatment-Seeking Patients With Opioid Use DisorderThis study is examining the use of Tezampanel (TZP) for treatment of Opioid Withdrawal Syndrome (OWS) in participants with Opioid Use Disorder (OUD). Participants will receive TZP or placebo (PBO) daily on Days 2 - 7 during a 7-day inpatient stay at the research center to determine safety, pharmacokinetic (PK) assessment, and efficacy of TZP for OWS.