The vestibulo-ocular reflex (VOR) under the influence of cinnarizine

In a double-blind, placebo controlled, crossover study, we evaluated the effects of cinnarizine on the VOR of 55 healthy young subjects. VOR was evaluated by the Sinusoidal Harmonic Acceleration (SHA) test at frequencies of 0.01, 0.02, 0.04, 0.08 and 0.16 Hz. There was a reduction in VOR gain in 16 of the 20 SHA trials performed under the influence of cinnarizine alone (25 mg and 50 mg) and cinnarizine 25 mg in combination with 10 mg domperidone or 1 transdermal scopolamine patch. This decrease in VOR gain was significant in only a few SHA trials. Phase lead was not consistently affected by cinnarizine. No notable side effects were found for any of the drug groups. Our findings are in accord with the contention that increased resistance to seasickness produced either by drugs, or by the natural process of habituation to sea conditions, may be reflected by a decrease in VOR gain.