A placebo-controlled assessment of mequitazine and astemizole in tests of psychomotor ability.

This study was a single and repeated dose comparison of mequitazine 5 mg, astemizole 10 mg and placebo and their effects on CNS activity, psychomotor performance and subjective appraisals of alertness. Nine Caucasian female volunteers aged between 29 and 40 years, declared healthy following a medical examination and who showed sensitivity to antihistamine sedation, were admitted to the study. Subjects were allocated to treatment in a randomized block design by which each subject received single and repeat doses of mequitazine 5 mg, astemizole 10 mg and placebo under double-blind conditions. Objective assessments (choice reaction time, critical flicker fusion threshold, simulated car tracking task, Stroop test) and subjective assessments (sedation and sleep rating scales, adverse effects and event recording) were made. Assessments were performed on day 1 and day 8 at pre-dosing (0 h) and at 1.5, 3.5 and 5.5 h following drug administration. Choice reaction times were dissimilar 5.5 h post-drug administration, the mequitazine group having a reaction time comparable to baseline and faster than the astemizole and placebo treatment groups. However, none of the treatments produced any significant or consistent effects when assessed on objective and subjective measures of performance, critical flicker fusion threshold, sedation and sleep and there were no treatment differences in the nature and number of adverse effects reported.