The cognitive impact of anticholinergics: a clinical review.

CONTEXT: The cognitive side effects of medications with anticholinergic activity have been documented among older adults in a variety of clinical settings. However, there has been no systematic confirmation that acute or chronic prescribing of such medications lead to transient or permanent adverse cognitive outcomes.

OBJECTIVE: Evaluate the existing evidence regarding the effects of anticholinergic medications on cognition in older adults.

DATA SOURCES: We searched the MEDLINE, OVID, and CINAHL databases from January, 1966 to January, 2008 for eligible studies.

STUDY SELECTION: Studies were included if the anticholinergic activity was systematically measured and correlated with standard measurements of cognitive performance. Studies were excluded if they reported case studies, case series, editorials, and review articles.

DATA EXTRACTION: We extracted the method used to determine anticholinergic activity of medications and its association with cognitive outcomes.

RESULTS: Twenty-seven studies met our inclusion criteria. Serum anticholinergic assay was the main method used to determine anticholinergic activity. All but two studies found an association between the anticholinergic activity of medications and either delirium, cognitive impairment or dementia.

CONCLUSIONS: Medications with anticholinergic activity negatively affect the cognitive performance of older adults. Recognizing the anticholinergic activity of certain medications may represent a potential tool to improve cognition.