Opposing the actions of the neu- rotransmitter acetylcholine. Anticholinergic drugs inhibit the transmission of parasympathetic nerve impulses, thereby reducing spasms of smooth mus- cles (for example, muscles in the bladder). Side effects of anticholinergic medications include dry mouth and related dental problems, blurred vision, tendency toward overheating (hyperpyrexia), and in some cases, dementia-like symptoms.