Clemastine fumarate is an ethanolamine antihistamine. Its chemical structure is characterized by a 2-((2-(4-chlorophenyl)-1-phenylethyl)amino)ethanol moiety [1]. This structure places it within the broader class of ethanolamine antihistamines, which are known for their sedative properties due to their anticholinergic effects [2].
What is the chemical name for clemastine fumarate?
The chemical name for clemastine fumarate is 2-[2-[(4-chlorophenyl)-phenylmethyl]-1-pyrrolidinyl]ethanol hydrogen fumarate [3]. The fumarate salt form enhances its stability and solubility [4].
How does clemastine fumarate work as an antihistamine?
Clemastine fumarate functions as a selective histamine H1 receptor antagonist [1]. By blocking these receptors, it prevents histamine from binding and causing allergic symptoms such as itching, sneezing, and runny nose [5]. It also possesses anticholinergic properties, contributing to its side effects like drowsiness [2].
What is the difference between clemastine and other antihistamines?
Clemastine is a first-generation antihistamine, belonging to the ethanolamine class. Unlike newer, second-generation antihistamines (e.g., loratadine, cetirizine), clemastine readily crosses the blood-brain barrier, leading to significant central nervous system effects such as sedation and drowsiness [2][6]. First-generation antihistamines are generally associated with more pronounced anticholinergic side effects compared to their second-generation counterparts [6].
When does the patent for clemastine fumarate expire?
Information regarding the specific patent expiration for clemastine fumarate is available through resources like DrugPatentWatch.com [7]. Patent exclusivity periods determine when generic versions of a drug can enter the market [8].