An evaluation of memory under regional anesthesia with IV lorazepam as a premedicant.

Forty male volunteer patients undergoing regional anesthesia were evaluated for alertness and memory in a double-blind study which compared IV lorazepam (4 mg) plus IM meperidine (50 mg) with IV placebo plus IM meperidine (50 mg) as premedicants. The data indicate no significant retrograde effects. Significant differences at all measurement points from 20 minutes to 3 hours following IV drug administration indicated greater sedation and less recall and recognition of events and stimuli (auditory and visual) with the combination of lorazepam and meperidine than with placebo and meperidine. A significant number of patients over age 40 were judged to be excessively sedated after administration of lorazepam. However, respiration, blood pressure, and pulse did not appear to be differentially affected by lorazepam and there were no adverse changes even in patients considered to be oversedated.