Transdermally administered scopolamine vs. dimenhydrinate. I. Effect on nausea and vertigo in experimentally induced motion sickness.

The effect of transdermally administered scopolamine (TTS-scopolamine) (2.5 cm2 surface area, one and two patches) and dimenhydrinate (100 mg) on experimental motion sickness was examined in 16 healthy volunteers in a randomized double-blind study. Nausea was induced by Coriolis manoeuvre and vertigo by calorization of the ear. In all subjects, scopolamine was found in urine in concentrations indicating adequate absorption of the drug. One TTS-scopolamine, two TTS-scopolamine and dimenhydrinate caused a statistically significant reduction in nausea when compared with placebo. Dimenhydrinate was somewhat more effective against nausea than one TTS-scopolamine. Vertigo was significantly reduced after dimenhydrinate and two TTS-scopolamine. Side effects of both drugs were negligible, though gait disturbances and vertigo could occur occasionally after two TTS-scopolamine. No dose-response relationship was found between the urinary excretion of scopolamine and alleviation of nausea. Dimenhydrinate and TTS-scopolamine are both effective against motion sickness, the latter provided it is applied 6 to 8 hours before exposure to the stimulus causing the motion sickness.