An<unk>  agent is a member of a class of pharmaceutical compounds (such as Dicyclomine) which serve to reduce the effects mediated by acetylcholine in the central nervous system and peripheral nervous system.<unk> s are typically reversible competitive inhibitors of one of the two types of acetylcholine receptors, and are classified according to the receptors that are affected:
antimuscarinic agents operate on the muscarinic acetylcholine receptors. (The majority of<unk> s are antimuscarinics.)
antinicotinic agents operate on the nicotinic acetylcholine receptors.
Anticholinergic
Sympatholytic
Antagonist 
Anticoagulant
Nicotinic antagonist
Ganglionic blocker
Sympathomimetic amine
Alpha-adrenergic agonist