NMA: Nonprescription Medicines Academy

Anticholinergic Agents Cause Cognitive Impairment in Older Adults in As Little As Two Months

May 29th, 2013

The results of a 1-year retrospective cohort study conducted in primary care clinics in Indianapolis, Indiana, indicate that drugs with strong anticholinergic effects (e.g., diphenhydramine) cause cognitive impairment in older adults when taken continuously for as few as 60 days. Taking multiple drugs with weaker anticholinergic effects (e.g., cimetidine, ranitidine, loperamide) have a negative impact on cognition in 90 days.

The study included 3,690 adults 65 years of age or older who had undergone cognitive assessment and had a 1-year medication-dispensing record. A two-stage procedure was used to screen eligible participants for dementia; participants with positive screening results were invited to participate in formal diagnostic assessments, which included a standardized neuropsychological testing, neurological examinations, medical record review, and a structured interview with an informal caregiver such as spouse, child, or other relative. Exposure to anticholinergic agents was defined by the duration of exposure, the number of anticholinergic medications dispensed at the same time, and the severity of anticholinergic effects as determined by the Anticholinergic Cognitive Burden (ACB) list.

Of the 285 participants who completed the full diagnostic assessment, 129 were considered to have dementia and 93 participants were considered to have mild cognitive impairment (MCI). The crude risk of having cognitive impairment was increased by 50% (among participants receiving at least three mild anticholinergic agents for >90 days) to 100% (among participants receiving one or more severe anticholinergic agents for >60 days).Compared with older adults with no exposure to anticholinergic agents—and after adjusting for age, race, gender, and underlying comorbidity—the odds ratio for having a diagnosis of MCI was 2.73 (95% CI, 1.27–5.87) among older adults who were exposed to at least three possible anticholinergic agents for at least 90 days. The odds ratio for having dementia was 0.43 (95% CI, 0.10–1.81).

Alzheimers Dement. 2012 Nov 22. [Epub ahead of print]