A Cochrane review [Abstract] 1 included 14 studies with a total of 1 025 subjects. Studies were generally small in size and of varying quality. Scopolamine was administered via transdermal patches, tablets or capsules, oral solutions or intravenously. Scopolamine was compared against placebo, calcium channel antagonists, antihistamine, methscopolamine or a combination of scopolamine and ephedrine. Five studies showed a superior effect of transdermal scopolamine over placebo for preventing sickness symptoms (RR 0.47; 95% CI 0.31 to 0.71). Comparisons between scopolamine and other agents were few and suggested that scopolamine was superior (vs. methscopolamine) or equivalent (vs. antihistamines) as a preventative agent. Evidence comparing scopolamine to cinnarizine or combinations of scopolamine and ephedrine is equivocal or minimal. Although sample sizes were small, scopolamine was no more likely to induce drowsiness, blurring of vision or dizziness compared to other agents. Dry mouth was more likely with scopolamine than with methscopolamine or cinnarizine.
Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison).
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