The effects of remoxipride and chlorpromazine on eye movements and psychomotor performance in healthy volunteers

Abstract

Fifteen healthy male volunteers received single doses of 100 mg immediate release remoxipride (IR), 150 mg controlled release remoxipride (CR), 50 mg chlorpromazine (CPZ), 2 mg lorazepam (LZ), and placebo in a randomised, five-period cross-over study. Both saccadic (SEM) and smooth pursuit eye movements (SPEM) as well as a battery of psychomotor performance tests were assessed at 1.5-h intervals over 9 h following drug administration. The areas under the response-time curves and the maximum effect during the study period were analysed by analysis of variance. The most consistent impairments were produced by LZ. The neuroleptics caused impairments to SEM, and tended to impair critical flicker fusion, continuous attention and both paced and unpaced versions of the digit-symbol substitution test as well as subjective measures of sedation. Only LZ impaired SPEM. Neither paced nor unpaced psychomotor tests distinguished between neuroleptics and benzodiazepines. The low therapeutic doses of IR and CR produced similar impairments to a sub-therapeutic dose of CPZ. Selectivity of pharmacological action does not appear to predict selectivity of effect on psychomotor function.