ABSTRACT
Postoperative pain causes various problems such as medical complications, excess cost and administration of opioid drugs. Although previous studies have shown the preventive effect of ketamine on postoperative pain, the administered dose was high [over 1mg/kg], which may cause adverse effects. The aim of this study was to assess the effect of low dose [0.5 mg/kg] of ketamine on postoperative pain. Sixty women that were candidate for elective cesarean section were recruited for our study and were divided randomly into two groups of case and control. Sixty seconds before operation, case and control groups received 0.5 mg/kg ketamine or placebo, respectively. Techniques of anesthesia and surgery were the same. Pain severity was assessed by McGill pain questionnaire, at 4 visits [the first at recovery then every 6 hours]. Case patients showed a lower mean pain score [P<0.05, t-test]. study suggests that low dose of ketamine is an effective drug for postoperative pain, which could be considered as an alternative of its high dose