Background: The most common pharmacological agents for alleviating symptoms of motion sickness in the U.S. are over-the-counter antihistamines. Two example are dimenhydrinate (Dramamine) and cyclizine (Marezine).
Hypothesis: Dramamine and Marezine suppress overall motion sickness symptoms with equal effectiveness, but Dramamine affects the central nervous system (CNS), while Marezine affects the stomach directly.
Methods: This study employed a double-blind, within-subject design to compare the effectiveness of Marezine (50 mg) and Dramamine (50 mg), in preventing subjective symptoms and gastric dysrhythmias associated with motion sickness. The sedative effects of the two drugs were also compared. Electrogastrograms (EGGs) were recorded from 23 subjects during 2 counterbalanced sessions for 3 trial periods: an 8-min pre-drug baseline, an 8-min pre-rotation baseline, which began 30 min after drug ingestion, and a 16-min period of exposure to a rotating optokinetic drum. Subjects reported any subjective symptoms of motion sickness (SSMS) and drowsiness before and during induction of motion sickness.
Results: There were no statistically significant differences between the two drug conditions for the overall mean SSMS scores. However, when the scores were divided into symptom groups, Marezine was associated with significantly lower scores than Dramamine for gastrointestinal (GI) symptoms. Also, Marezine was associated with significantly less drowsiness than Dramamine 30 min after ingestion. Power in both the normal (3 cpm) and tachyarrhythmia (4-9 cpm) ranges of the EGG increased significantly more during rotation compared to baseline in the Dramamine condition than in the Marezine condition.
Conclusions: Marezine and Dramamine are similarly effective in preventing the overall subjective symptoms of motion sickness. While Dramamine's effectiveness may be related to its sedative properties, Marezine may work more directly on the stomach and thus be more effective in preventing gastric dysrhythmias and reports of GI symptoms.