PHENYTOIN FOR MOTION SICKNESS - CLINICAL-EVALUATION

Phenytoin has previously been shown to protect against motion sickness induced by Coriolis stimulation. The purpose of our series of investi gations was to investigate further the efficacy of phenytoin for motio n sickness prophylaxis and to gain insight into its mechanism of actio n. We tested participants with electronystagmography, off-vertical rot ation, sea travel, and parabolic flight after they received phenytoin or placebo. Blood levels of at least 9 mu g/mL were found to protect a gainst motion sickness. Electronystagmography showed significant decre ases in the gain of the vestibuloocular reflex in participants receivi ng phenytoin. Few side effects were seen with drug levels in the 9 to 15 mu g/mL, range. Phenytoin is an effective motion sickness counterme asure that may exert its effect through a combination of central nervo us system and peripheral vestibular effects.