Meclizine

Meclizine (proposed INN is meclozine) is an antihistamine considered to be an antiemetic.[1] It is sold under the brand names of Bonine, Bonamine, Antivert and Postafen and is most commonly used to inhibit nausea and vomiting. Emesafene is a combination of meclizine (1/3rd) and pyridoxine (2/3rd). An alternative to dimenhydrinate (Dramamine), meclizine is considered to be equally effective, but with reduced side effects. Note that in Canada, Antivert (no longer available) was a combination of meclizine and nicotinic acid.
Meclizine is a first-generation antihistamine of the piperazine class. It differs from the protoype of this class, cyclizine, primarily in having a 12-hour duration of action.[citation needed] Meclizine is less anticholinergic than many other antihistamines and other agents used for their anti-emetic and anti-pruritic effects.[citation needed]Along with the aforementioned efficacy against nausea and itching, meclizine also shares the anxiolytic, analgesic-sparing (potentiating), sedative, and other effects of its chemical relatives cyclizine and hydroxyzine to varying extents.[citation needed] Related to this is the reported ability of meclizine to potentiate the anti-spasmodic, anti-diarrhoeal, and other effects of diphenoxylate, loperamide, and difenoxin.[citation needed]