Backgrond & Objectives: Perioperartive shivering is a common complication which interferes with monitoring of patients and it increases oxygen consumption (up to 500%) which can be life-threating in patients with a low cardio pulmonary reserve. This study compared the efficiency and complications of two perioperative antishivering drugs. (Tramadol and Meperidine).

  Methods: All of the 70 patients under went cesarean section with spinal Anesthesia, were categorized in two groups of 35 persons, and treated as clinical trial, double blind with tramadol and meperidine. Then they were compared in terms of the interval between administration of drugs and stoping of shivering and their complications.

  Results : The mean age in patient were 27 years, youngest one was 17 and the oldest was 39 years. The average interval of stopping of shivering during tramadol using (2.57 min) is less than meperidine (6.24 min). The frequency of nausea and vomiting in meperidine group was more than that of the tramadol group. Regarding the incidence of pruritus and sedation after using of drug in both groups, there was no considerable difference between them. Respiratory and pulse rate changes, and decreasing of arterial oxygen saturation in post injection period to preinjection period of meperidine, didn't show any significant changes. In systolic and diastolic blood pressure changes, there was no significant change in both groups.

  Conclusion: Perioperative shivering treatment by tramadol is better than meperidine because of its faster onset of stopping of shivering and its low complications in cesarean section with spinal anesthesia.