Motion Sickness Management

Antihistamine Efficacy

First-generation antihistamines, such as dimenhydrinate and meclizine, are effective for motion sickness because they cross the blood-brain barrier and affect central nervous system function, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
Second-generation antihistamines like fexofenadine have minimal to no sedative effects at recommended doses and lack the central nervous system effects needed to prevent motion sickness, as reported in the Journal of Allergy and Clinical Immunology 2, 3

First-generation antihistamines can cause sedation and performance impairment, with 66% of users experiencing sedation and drowsiness, and may increase the risk of accidents when driving or operating machinery, as noted in the Journal of Allergy and Clinical Immunology 4
Particular caution should be used in older adults, patients with glaucoma, prostatic hypertrophy, or cognitive impairment, and those taking other CNS depressants, including alcohol, due to increased sensitivity to adverse effects, as advised in the Journal of Allergy and Clinical Immunology 4

Diphenhydramine, a first-generation antihistamine, is effective for motion sickness, according to the American Academy of Otolaryngology-Head and Neck Surgery 1