Phenytoin for motion sickness: clinical evaluation

Area of Science:

• Neuroscience
• Vestibular Science
• Pharmacology

Background:

• Phenytoin (an anticonvulsant) has demonstrated protective effects against motion sickness.
• Further investigation is needed to confirm its efficacy and understand its mechanism.

Purpose of the Study:

• To further evaluate phenytoin's effectiveness in preventing motion sickness.
• To explore the underlying mechanisms of phenytoin's anti-motion sickness action.

Main Methods:

• Participants received phenytoin or placebo.
• Evaluations included electronystagmography, off-vertical rotation, sea travel, and parabolic flight.
• Blood phenytoin levels were monitored.

Main Results:

• A blood level of at least 9 micrograms/mL was associated with protection against motion sickness.
• Phenytoin administration led to significant reductions in vestibuloocular reflex gain.
• Minimal side effects were observed within the therapeutic range (9-15 micrograms/mL).

Conclusions:

• Phenytoin is a viable option for motion sickness prevention.
• Its efficacy may stem from combined central nervous system and peripheral vestibular system effects.