clemastine

:  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, March 1997