Midazolam: Effects on Amnesia and Anxiety in Children

Background: The minimum time interval between administration of oral midazolam and separation of children from their parents that ensures good anterograde amnesia has not been previously determined. This is of particular importance in a busy operating room setting where schedule delays secondary to midazolam administration may not be tolerated.

Methods: Children (n = 113) undergoing general anesthesia and surgery completed preoperative baseline memory testing using a validated series of picture cards and were randomly assigned to one of three midazolam groups or a control group. Exactly, 5, 10, or 20 min after receiving oral midazolam (0.5 mg/kg) or 15 min after receiving placebo, children were administered a second memory test that used pictures. Anxiety of children was assessed during induction of anesthesia with use of a validated anxiety measurement tool. Postoperatively, recall and recognition for picture cards seen during baseline testing and postintervention testing were assessed.

Results: Postoperatively, recall and recognition of pictures presented to patients after drug administration (anterograde amnesia) showed significant group differences (P = 0.0001), with recall impaired in the 10- (P = 0.004) and 20-min groups (P = 0.0001). Similarly, recognition memory was impaired in the 5- (P = 0.0008), 10- (P = 0.0001) and 20-min (P = 0.0001) groups. Significant anxiolytic effects of midazolam were observed as early as 15 +/- 4 min after midazolam administration (P = 0.02).

Conclusions: Midazolam administered orally produces significant anterograde amnesia when given as early as 10 min before a surgical procedure.