Motion Sickness and Human Performance Laboratory, Israel Naval Medical Institute, Haifa.
Cinnarizine was evaluated for the prevention of seasickness in a laboratory and sea study. The effects of 25 mg cinnarizine on the vestibulo-ocular reflex were investigated in 13 subjects. Significant reduction of the gain in response to sinusoidal oscillations at 0.02, 0.08, and 0.16 Hz (p < 0.05) and increased phase lead at 0.16 Hz (p < 0.01) were observed. The effect of 25 and 50 mg cinnarizine on seasickness severity was examined in 95 subjects during a voyage in rough seas. Seasickness symptoms were improved in 69% of the subjects by 50 mg cinnarizine versus 35% and 31% in the groups receiving 25 mg cinnarizine and placebo (p < 0.05 and p < 0.01, respectively). The percentage of vomiting protection provided by 50 mg cinnarizine was 63% (p < 0.05). We conclude that 50 mg cinnarizine is an effective drug for the prevention of seasickness. The reduction in vestibular sensitivity observed even after administration of 25 mg cinnarizine may explain the potency of cinnarizine in the prevention of seasickness.