Influence of 3 antivertiginous medications on the vigilance of healthy volunteers.

In the present randomized, comparative, double-blind, 3-way crossover study, possible effects of 3 antivertiginous medications on vigilance were investigated. 30 healthy volunteers received single doses of a fixed combination of cinnarizine 20 mg and dimenhydrinate 40 mg (Arlevert, ARL), dimenhydrinate 50 mg, or betahistine dimesylate 12 mg, in randomized order at 1-week intervals. Spontaneous brain electrical activity (EEG), acoustic late evoked potentials (ALEP) with P300, and reaction time were measured before and 90 (t90) and 180 minutes (t180) after drug intake. All 3 medications led to a delay of P300 (primary criterion) and a decrease of its amplitude. The maximum delay at t180 was found for dimenhydrinate (16.42 ms) and the lowest for betahistine (6.33 ms). Differences ARL vs dimenhydrinate and ARL vs betahistine were not statistically significant (p > 0.05). Spectral analysis of spontaneous EEG showed slight and similar decreases in the power in the a-band under dimenhydrinate and ARL (p = 0.07 and p = 0.03 with respect to baseline, respectively), but basically no change under betahistine. There was no effect on reaction time by either medication. None of the subjects reported drowsiness or any other adverse event. The findings confirm the reported suitability of P300 latency for measurement of drug effects on brain activity, but provide no indication of concomitant impairment of performance capacity by the tested drugs. Global assessment of the results suggests that the fixed combination cinnarizine 20 mg/dimenhydrinate 40 mg exerts only a minor effect on vigilance, not significantly different from betahistine, which is commonly regarded as a non-sedating antivertiginous drug