Absence of analgesic effect of intravenous melatonin administration during daytime after laparoscopic cholecystectomy: a randomized trial.

STUDY OBJECTIVE

To investigate whether melatonin administered intraoperatively reduced pain following laparoscopic cholecystectomy.

DESIGN

Randomized, placebo-controlled, double-blinded study.

SETTING

Two surgical departments in Copenhagen.

PATIENTS

44 women between 18 and 70 years of age, who were surgical candidates for laparoscopic cholecystectomy.

INTERVENTIONS

Patients were anesthetized by a standard protocol and received a standard multimodal postoperative analgesic regimen. Patients undergoing surgery were admitted on the day of surgery and were discharged the day after surgery. Ten mg of intravenous (IV) melatonin or placebo were administered at the time of surgical incision.

MEASUREMENTS

Pain was assessed by a set of questionnaires documenting "pain at rest" using a visual analog scale (VAS). The use of rescue medication was recorded. Sleep quality and general well-being were measured on separate VAS scales. Sleepiness was assessed by the Karolinska Sleepiness Scale.

MAIN RESULTS

Forty-four patients were included and randomized to the study. Three patients did not complete the study. No differences in VAS pain scores, sleep quality, general well-being, or sleepiness were found between the two groups in the postoperative period. The use of postoperative rescue medication did not differ between the groups.

CONCLUSIONS

The use of 10mg of IV melatonin administered during laparoscopic cholecystectomy did not affect postoperative pain or use of analgesic medication.