 This study is designed to evaluate dexmedetomidine as adjunctive therapy of severe alcohol withdrawal of medical ICU patients. Specifically, this study will assess whether adjunctive dexmedetomidine reduces the doses of conventional agents used for alcohol withdrawal while maintaining patient comfort and safety and will explore if dexmedetomidine exhibits a dose-dependent profile of action when it is used for this indication. In addition, this study will assess the relationships between alcohol withdrawal, therapy with dexmedetomidine, and potential serum biomarkers of alcohol withdrawal. 