BXCL501 After Stress to Increase Recovery Success

This study will examine the safety and efficacy of BXCL501 to reduce ASR symptoms and behavioral changes among patients presenting to the Emergency Department (ED) after Motor Vehicle Collision (MVC). Specifically, the investigators will perform the BXCL501 (BASIS) Trial, a double-blind placebo-controlled Randomized Controlled Trial (RCT) to determine if BXCL501 (dexmedetomidine hydrochloride sublingual film) initiated in the ED in the hours after MVC to high risk individuals, treats/reduces ASR/ASD symptoms (primary outcome), improves neurocognitive function, and prevents/reduces posttraumatic stress (PTS) symptoms (secondary outcomes) long term. 100 participants will be randomized, receive study drug in ED and be discharged with a 2-week drug supply. Prior to initial dose of study drug administration, and during the hours, days, and weeks after participants will receive serial longitudinal assessments of psychological and somatic symptoms, neurocognitive function, and adverse events.