Several tricyclic antidepressants have been assessed for their potency in binding to the muscarinic acetylcholine receptor of brain and intestine. Amitriptyline hydrochloride is about ten times as potent as imipramine hydrochloride. Dimethylated drugs are more potent than monomethylated ones. The relative anticholinergic activities of tricyclic antidepressants have implications for their use in patients who might be affected adversely by anticholinergic effects.
