Anticholinergic effects refer to the inhibition of the neurotransmitter acetylcholine in the central and peripheral nervous system, leading to a range of symptoms such as dry mouth, blurred vision, constipation, urinary retention, and cognitive impairment. These effects are often associated with the use of certain medications, including antihistamines, tricyclic antidepressants, and antipsychotics, and can be particularly problematic in elderly patients due to increased sensitivity and risk of side effects.