Inclusion Criteria:  Patients scheduled to undergo elective thyroidectomy under general anesthesia American Society of Anesthesiologists (ASA)physical classification I-II Willingness and ability to sign an informed consent document  Exclusion Criteria:  American Society of Anesthesiologists (ASA)physical classification III or more BMI > 40kg/m^2 Allergies to anesthetic or analgesic medications (benzodiazepines, propofol, remifentanil, fentanyl citrate, rocuronium bromide, sugammadex, flumazenil) Patients who receive mechanical ventilation morethan 2 hours after surgery Patients who receive the following medications within 24 hours prior to general anesthetics: anxiolytics, antipsychotics, rifampicin, succinycholine, neostigmine, flumazenil, cyclosporin Patients with galactose intolerance or Lapp Lactase deficiency or glucose-galactose malabsorption Medical or psychological disease that can affect the treatment response