GABAPENTIN AND CARBAMAZEPINE AFFECT EYE-MOVEMENTS AND POSTURE CONTROLDIFFERENTLY - A PLACEBO-CONTROLLED INVESTIGATION OF ACUTE CNS SIDE-EFFECTS IN HEALTHY-VOLUNTEERS

This prospective study examined the effects of the new antiepileptic d rug (AED) gabapentin (GBP) compared to the standard AED carbamazepine (CBZ) and placebo (PLA) on eye movements, posture and finger force con trol in 12 healthy volunteers who received single doses of 600 mg GBP and 400 mg CBZ in a placebo-controlled, double-blind, cross-over, rand omized trial. CBZ and GBP reduced almost equally (8% vs. 10%) the mean peak saccade velocity as compared to PLA (P < 0.05). CBZ, but not GBP , significantly prolonged the duration of saccades as compared to plac ebo (14-24%) (P < 0.05). GBP produced a greater maximal increase of bo dy sway than CBZ with eyes open (P < 0.01) and eyes closed (P < 0.001) . CBZ and GBP did not significantly influence control of grip force. C BZ effects were better correlated with plasma levels. Subjective side effects were more pronounced with CBZ than GBP. Although CBZ and GBP c ause similar CNS side effects, the effects on eye movements and body s way were different. CBZ predominantly affects saccadic eye movements, whereas GBP had more impact on posture control. Thus, electro-oculogra phy seems to be more appropriate in the detection of CBZ-induced side effects and posturography appears to be more sensitive in the detectio n of side effects associated with GBP. (C) 1998 Elsevier Science B.V. All rights reserved.