Preemptive use of diclofenac in combination with ketamine in patients undergoing laparoscopic cholecystectomy: a randomized, double-blind, placebo-controlled study.

BACKGROUND

To examine the combined preemptive effects of low-dose ketamine, diclofenac, and their combination on postoperative pain in patients undergoing laparoscopic cholecystectomy.

METHODS

A total of 80 consecutive patients, American Society of Anesthesiologists physical status I or II, were recruited to the study. Patients were randomized to one of the following groups: group 1 received 100-mL isotonic saline intravenously (i.v.) 20 minutes before the induction of anesthesia and 5-mL isotonic saline i.v. before skin incision as a placebo; group 2 received 100-mL isotonic saline i.v. 20 minutes before the induction of anesthesia and 0.15-mg/kg ketamine diluted in 5-mL isotonic saline i.v. before skin incision; group 3 received diclofenac 1 mg/kg diluted in 100-mL isotonic saline i.v. 20 minutes before the induction of anesthesia and 5-mL isotonic saline i.v. before skin incision; and group 4 received a combination of the same diclofenac sodium and ketamine doses at the same time. Abdominal and shoulder pain intensity was assessed using the visual analog scale and verbal rating scale during 24 hours postoperatively.

RESULTS

Patients receiving diclofenac had a significantly lower pain score between 2 and 6 hours after surgery compared with patients receiving placebo. One hour after surgery, patients receiving a combination of diclofenac and ketamine had a significantly lower pain score compared with patients receiving placebo and ketamine alone. Patients from all the 4 study groups required postoperative analgesic; however, the time to diclofenac sodium request was longer in patients receiving a combination of diclofenac and ketamine compared with patients receiving placebo (p<0.001), ketamine (p<0.001), or diclofenac (p=0.03) alone.

CONCLUSIONS

The preemptive administration of a combination of low-dose ketamine plus diclofenac sodium improved postoperative analgesia after laparoscopic cholecystectomy, whereas ketamine at a dose of 0.15 mg/kg did not elicit a preemptive analgesic effect.