Effects of a single 1200-mg preoperative dose of gabapentin on anxiety and memory

Gabapentin has antihyperalgesic and potential anxiolytic effects. We therefore evaluated the effects of gabapentin premedication on anxiety, amnesia, and sedation. We tested the primary hypothesis that 1200mg of oral gabapentin 2 to 3h before surgery reduces preoperative anxiety. Our secondary hypothesis was that gabapentin administration is sedative without causing preoperative amnesia.

Prospective, randomized and placebo-controlled study.

Surgical patients having general anaesthesia were randomly assigned to either 1200mg oral gabapentin (n=32) or an identical-looking placebo (n=32) 2 to 3h before anaesthesia. Anxiety, sedation, and amnesia were quantified before premedication, 2h thereafter, and postoperatively. Preoperative anxiety was measured using the Spielberger state trait anxiety inventory (STAI state) and the visual analogue scale anxiety (VAS). Memory was assessed with the picture recall test of Snodgrass and Vanderwart. Results were compared with t, Mann-Whitney U, or Chi(2) tests as appropriate, P<0.05 was considered statistically significant.

STAI state, our primary outcome, decreased significantly in the gabapentin group, from 37.2 to 30.8, and remained unchanged in the placebo group, from 39.3 to 37.9 (P=0.003). The VAS score for anxiety also decreased, but not significantly, from 28.2 to 19.2 in the gabapentin group and from 28.7 to 24.7 in the placebo group (P=0.065). No difference was observed in the amnesic effect; nor did the groups differ in terms of recovery times or sedation scores.

Gabapentin premedication, 1200mg, provided preoperative anxiolysis without causing sedation or impairing preoperative memory.