Scopolamine for patients with motion sickness: a systematic review and meta-analysis with trial sequential analysis

BackgroundScopolamine has been demonstrated to relieve motion sickness. However, repeated significance testing may increase false-positive results. ObjectivesReview the efficacy and safety of scopolamine in the prevention of motion sickness by performing a meta-analysis with Trial Sequential Analysis (TSA). Material and methodsRandomized controlled trials (RCTs) compared scopolamine with other medications or placebo were included. Primary outcomes were nausea reported and head movement time. ResultsTwenty studies with 753 participants were included. Scopolamine had a greater reported reduction in nausea than placebo (relative risk [RR] 0.35; 95% confidence interval [CI] 0.24 to 0.52; p<0.00001; I2 = 45%), while TSA showed the included sample size exceeded the required information size (RIS). There is no difference in head movement time between scopolamine and placebo (mean difference [MD] 2.02; 95% CI -1.2 to 5.25; p = 0.6; I2 = 0%), while the included sample size did not reach RIS. ConclusionScopolamine is effective for motion sickness nausea compared to placebo. The TSA recommends conducting more head movement trials to validate the objective efficacy of scopolamine. SignificanceClarifying the efficacy of scopolamine for motion sickness, the TSA highlights the need for more prospective studies using head movement as an outcome.