Motion Sickness Medications and Vestibular Time Constant

Detailed Summary

Sea sickness represents a major limitation on the performance of ships' crew. One of the challenges faced by the physician in the motion sickness clinic when prescribing anti-sea sickness medication is to select the appropriate drug for the patient. Difficulties arise due to high variability in the response to different drugs. In the case of sea sickness, the current procedure is to examine the drug's efficacy in each individual during real time exposure to sea conditions. A number of studies have documented the presence of sea sickness drug receptors in the vestibular nuclei, which determine the vestibular time constant. Two clinical vestibular tests which evaluate the time constant are the Velocity Step and OKAN tests. The purpose of the proposed study is to evaluate the influence of motion sickness drugs on the vestibular time constant, as a possible bioequivalent of drug potency in the individual subject. Eighty crew members will be recruited and divided into groups responsive and non-responsive to the sea sickness drugs scopolamine and meclizine. Subjects having a Wiker score of 7 in waves 1 meter high without drug treatment, and no improvement in symptoms after treatment will be defined as non-responsive to sea sickness drugs. Subjects having a Wiker score of 7 in waves 1 meter high without drug treatment, and a Wiker score of 4 or less after treatment, will be defined as responsive to drug therapy. Kwells, Bonine and placebo, will be assigned to each subject in a random, double-blind fashion. Each group will perform the Velocity Step and OKAN tests before, one and two hours after drug or placebo administration.

Study Details

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Interventions