Inclusion Criteria:  Scheduled for elective hysterectomy American Society of Anesthesiologists (ASA) physical status 1 to 3  Exclusion Criteria:  allergy to studied drugs history of chronic pain history of hepatitis, depression, peptic ulcer, or acute myocardial infarction receive intraoperative massive blood transfusion prolonged coagulation body mass index >35 kg/m2 patients with neurological deficits taking anti-platelet medications