Effects of Oxypertine and Chlordiazepoxide on Human Motor Co-Ordination

Abstract

The performance of six normal healthy male volunteers in three simple co-ordination tests has been used to assess the effects of three doses of oxypertine and one dose of chlordiazepoxide. In the first part of the study, single doses of oxpyertine ( 10 and 20 mg) and chlordiazepoxide 10 mg were compared, in the second part of the study, two doses of oxypertine 5 and 10 mg given four hours apart were compared. The tests employed were—braking reaction time in a motor car simulator, spatial co-ordination and pursuit rotor performance. In the first part of the study, oxypertine ( 10 and 20 mg) produced initial improvements in performance in the braking test, followed by deterioration. Performance four hours after 10 mg of oxypertine was normal when compared with the placebo response. Chlordiazepoxide 10 mg produced a deterioration in performance. Statistical analysis of the braking reaction times revealed large subject to subject variations, and in only one case was a statistically significant difference between treatments demonstrated. The second part of the study failed to confirm the improvements in performance noted in the earlier study. No statistically significant changes in performance were detected following the first capsules of oxypertine ( 5 or 10 mg). Three and four hours after consuming the second 5 or 10 mg capsule, significant changes in braking performances were recorded at the 1% and 5% levels of significance respectively. Performance in the pursuit rotor test was enhanced following the ingestion of 5 mg of oxypertine, but was depressed after 10 mg of the drug, these observations were not statistically significant. Dose related drowsiness was detected following dosage with oxypertine and although less obvious outwardly in later studies, it was still apparent in the performance scores of the subjects, particularly those who had consumed the higher ( 20 mg) dose of oxypertine. The braking reaction time experiments suggest that dosage with oxypertine at a frequency of 10 mg every four hours or less, may result in an accumulation of drug and lead to significant motor inco-ordination. It seems unlikely that prolonged dosage with the 5 mg dose of oxypertine will lead to accumulation of the drug.