Editing Motion sickness (section)

==== Antihistamines ====
First generation [[H1 antagonist|H1 antihistamine]] medications are sometimes given to prevent or treat motion sickness. This class of medication is often effective at reducing the risk of getting motion sickness while in motion, however, the effectiveness of antihistamines at treating or stopping motion sickness once a person is already experiencing it has not been well studied.<ref name=":0">{{Cite journal |last1=Karrim |first1=Nadine |last2=Byrne |first2=Ryan |last3=Magula |first3=Nombulelo |last4=Saman |first4=Yougan |date=2022-10-17 |title=Antihistamines for motion sickness |url= |journal=The Cochrane Database of Systematic Reviews |volume=2022 |issue=10 |pages=CD012715 |doi=10.1002/14651858.CD012715.pub2 |issn=1469-493X |pmc=9575651 |pmid=36250781 }}</ref> Effective first generation antihistamines include [[doxylamine]], [[diphenhydramine]], [[promethazine]], [[meclizine]], [[cyclizine]], and [[cinnarizine]].<ref name="Stat2019" /> In pregnancy meclizine, dimenhydrinate and doxylamine are generally felt to be safe.<ref name="Stat2019" /> Side effects include sleepiness.<ref name="Stat2019" /><ref name=":0" /> [[Second generation antihistamines]] have not been found to be useful.<ref name="Stat2019" />

Some, but not all, antihistamines used for motion sickness are also antimuscarinics.<ref name="Stat2019" />