• 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.