clemastine

noun

clem·​as·​tine ˈklem-ə-ˌstēn 

: an antihistamine drug administered orally in the form of its fumarate C₂₁H₂₆ClNO·C₄H₄O₄ to relieve the symptoms of hay fever and the common cold

… oral antihistamines, such as chlorpheniramine and clemastine, reduce sneezing and, to a lesser extent, rhinorrhea, probably because of their anticholinergic effects, but they are often associated with excess sedation.

—Frederick G. Hayden, Scientific American Medicine Bulletin