1 From the Department of Anesthesiology and Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, Missouri, and Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University in St. Louis, St. Louis, Missouri (E.D.K.); and the Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts (T.T.H.).