The Preventive Effect of Intramuscular Ketamine and Methadone on Postoperative Pain after Laparoscopic Cholecystectomy

The postoperative pain is one of the most common complications of laparoscopic cholecystectomy. To control this pain, analgesic drugs are commonly used. Therefore, considering the importance of this issue, the aim of this study was to determine the effect of pre-emptive intramuscular ketamine and methadone on postoperative pain after laparoscopic cholecystectomy.

In this double-blind clinical trial study, 90 patients undergoing laparoscopic cholecystectomy were included. Then, the patients were randomly divided into three equal groups. Preoperatively, the first group received 1.5 mg/kg ketamine, the second group received 0.15 mg/kg methadone, and the third group received normal saline intramuscularly. Hemodynamic changes, postoperative pain, rescue analgesia, and complications of the operation were investigated in the groups.

There was no significant difference between the groups based on hemodynamic changes, postoperative complications, and the rescue analgesia (P > 0.050). However, there was a significant difference between the groups according to the amount of pain after the operation; the postoperative pain was lower in methadone, ketamine, and placebo groups, respectively (P < 0.001).

Two drugs of ketamine and methadone are effective in reducing postoperative pain following laparoscopic cholecystectomy, but the effect of methadone is better than ketamine. Moreover, the use of these drugs is not associated with hemodynamic changes and postoperative complications.