Scopolamine prevents dreams during general anesthesia

Dreaming during anesthesia is not a well-understood phenomenon. Anticholinergic drugs are used in anesthesia as premedication, but their use to decrease the incidence of dreams and psychological adverse reactions after anesthesia is not well established. The authors therefore studied the efficacy of intramuscular atropine and scopolamine for the prevention of dreams during general anesthesia with propofol and nitrous oxide.

Healthy women undergoing minor gynecologic surgery were randomly assigned to receive 2.5 microg/kg scopolamine or 10 microg/kg atropine intramuscularly (n = 50/group). In both groups, anesthesia was induced and maintained with propofol as a 2.5-mg/kg bolus, followed by 12 mg x kg(-1) x h(-1) as a continuous infusion and 70% nitrous oxide in oxygen. Two interviews regarding dreaming activity and characteristics were conducted at 20 min and 6 h after surgery.

None of the patients in the scopolamine group and 47% of the patients in the atropine group reported the occurrence of dreams 20 min after recovery. The results were similar at 6 h: 6% of the scopolamine group and 43% of the atropine group reported dream activity. No differences in sedation or anesthetic requirements were found.

Previous studies in animals and humans suggest that dreams are affected by drugs acting on the central cholinergic system. The current results suggest that intramuscular scopolamine prevents dreams or dream recall in healthy young women undergoing short elective surgery with propofol-nitrous oxide anesthesia.