Motion Sickness and Human Performance Laboratory, Israeli Naval Hyperbaric Institute, Haifa.
In a double-blind, placebo-controlled study, we evaluated the effect of two different doses of cinnarizine in the prevention of seasickness in very rough seas. We divided 95 healthy male subjects into 3 groups which received: cinnarizine 50 mg, cinnarizine 25 mg, and placebo. Seasickness susceptibility and severity were evaluated by a standard questionnaire concerning the subject's condition on previous voyages (seasickness susceptibility), and the subject's condition immediately after a 4-6-h voyage in very rough seas with 3.5 m waves (seasickness severity). Possible side effects of the drug were also evaluated by filling in a further questionnaire. Of the 31 subjects who received cinnarizine 50 mg, 65% felt better during the present voyage than on previous voyages, compared to 41% of the 32 subjects who received cinnarizine 25 mg and 31% of the 32 who received placebo. A significant difference (p < 0.05) was found between the cinnarizine 50 mg and placebo groups, while cinnarizine 25 mg was no more effective than placebo. No notable side effects were found for any drug group. In conclusion, cinnarizine 50 mg was found to be effective in the prevention of seasickness in rough seas