Efficacy of Suvorexant on Post-operative Sleep Disturbance

The study is a parallel group, double blind, randomized trial. Subjects will be recruited from individuals undergoing elective surgery for orthopedic, abdominal, urologic, gynecologic or spine reasons. Out of 92 subjects, one experimental group of 46 subjects will receive 20 mg Suvorexant beginning the first in-hospital night ("day 0") and continuing for their hospital stay. If the dose is not well tolerated (e.g., daytime sleepiness), then the dose may be decreased to 10 mg of Suvorexant. For blinding purposes each arm will receive two tablets (two 10 mg tablets or one 10 mg tablet and a placebo). The other control group of 46 subjects will receive placebo (two tablets) and treatment as usual.