[1] Johns Hopkins Univ, Sch Med, Dept Med, Baltimore, MD 21205 USA
[2] Georgetown Univ, Sch Med, Dept Anesthesiol, Washington, DC USA
[3] NYU, Dept Anesthesiol & Pain Med, New York, NY USA
[4] Vanderbilt Univ, Med Ctr, Dept Psychiat & Anesthesiol, Nashville, TN USA
[5] NEMA Res Inc, Div Hlth Outcomes & Pharmacoecon, Naples, FL USA
[6] NEMA Res Inc, Div Pharmaceut Sci, Naples, FL USA
[7] Interdisciplinary Pain & Palliat Care Ctr, Goppingen, Germany
[8] Temple Univ, Dept Pharmacol, Sch Med, Philadelphia, PA 19122 USA