Impairment state of cognitive performance and the affecting factors in outpatients following gastrointestinal endoscopy after single-dose diazepam

Diazepam is commonly used as premedicant for endoscopic procedures. Wide interindividual differences have been observed in the residual cognitive effects of the drug after gastrointestinal endoscopy. Our aim was to clarify the major factors, including pharmacokinctic factors, contributing to this wide variation in residual cognitive effect after gastrointestinal endoscopy in the study. Sixty-one outpatients undergoing gastrointestinal endoscopy participated in the study. Cognitive effects were evaluated in the diazepam group (n=52) by the digit symbol substitution test (DSST) twice before and 30 min after an intravenous administration of 5 mg diazepam; in the intervening time gastrointestinal endoscopy was performed. Plasma concentrations of diazepam were determined by HPLC. The control group (n=9) was tested by DSST in the same manner. The cognitive effects according to the change in DSST score was significantly decline in the diazepam group compared with the control group (by 0.2 versus -4.6; P=0.014). This prospective study confirmed that cognition was significantly impaired after gastrointestinal endoscopy by premedication to subjects with 5 mg diazepam. There were very wide variations in change in DSST score. However we could not identify the independent variables that best predicted DSST score difference in a multiple regression analysis for age, plasma albumin level, and plasma diazepam concentration 30 min after intravenous administration. We should pay attention to patients' individual states in cognitive performance following gastrointestinal endoscopy after single-dose diazepam.