What type of antiemetic is often the first line of treatment for motion sickness?

Antihistamines are often the first line of treatment for motion sickness due to their ability to block histamine receptors in the vestibular system, which plays a crucial role in balance and spatial orientation. By interfering with the action of histamine, these medications can effectively reduce the symptoms associated with motion sickness, such as nausea, dizziness, and vomiting.

Antihistamines such as dimenhydrinate and meclizine are commonly used for this purpose because they have sedative effects and can diminish the excitability of the vestibular system. Their efficacy in preventing motion sickness makes them a preferred choice especially for individuals prone to symptoms during travel.

Other classes like serotonin receptor antagonists and dopaminergic agents may be useful for nausea and vomiting in other contexts (like chemotherapy-induced nausea), but they are not specifically effective for motion sickness. Glucocorticoids are primarily used in certain cases of severe nausea related to cancer treatments rather than motion sickness. Thus, antihistamines are widely recognized as the go-to option for preventing and treating motion sickness effectively.