Effects of Some Motion Sickness Suppressants on Tracking Performance during Angular Accelerations,

The two studies reported here examined the influence of three established antimotion sickness drugs on tracking performance in static stationary and dynamic angular acceleration conditions and on visual fixation ability during motion. In Study I, 40 young men were randomly assigned in equal numbers to either a control lactose placebo, dimenhydrinate 50 mg, promethazine hydrochloride 25 mg, or mixture 25 mg promethazine plus 10 mg d-amphetamine group. Study II used 30 new subjects equally divided into control, dimenhydrinate 100 mg, and promethazine 50 mg groups. Following practice, tests were conducted prior to 1, 2, and 4 hours after drug ingestion. The depressant drugs had little effect on static tracking, but impaired dynamic tracking performance and reduced ability to maintain visual fixation on a localizerglide slope instrument due to increased ocular nystagmus. The mixture of promethazine and d-amphetamine produced none of these deleterious effects.