Many older adults take one or more drugs with anticholinergic effects for health problems such as depression, allergies, incontinence, and gastroesophageal reflux. But a growing number of studies suggest that clinicians should be particularly cautious when prescribing these medications for elderly patients.

Possible side effects from drugs with anticholinergic effects include confusion, lightheadedness, blurred vision, constipation, dry mouth, difficulty urinating—and, as mounting evidence indicates, adverse effects on cognition in the elderly. In older patients taking multiple anticholinergic drugs for long periods of time, risks of these side effects appear to be magnified.

In a recent study published in the Journal of the American Geriatrics Society, Ling Han, MD, PhD, Joseph V. Agostini MD, and Heather G. Allore, PhD,1 of Yale University School of Medicine’s Program on Aging, examined the cumulative effects of anticholinergic drugs on memory and cognitive function in older adults and came to some sobering conclusions. The researchers analyzed the records of 544 community-dwelling men, all age 65 years and older, who had hypertension and were enrolled in the Connecticut Veterans Longitudinal Cohort study. Han and colleagues reviewed the records of the men’s primary care visits, focusing on their medication regimens, at baseline and each quarter of a 2-year follow-up period. The researchers also reviewed the men’s scores, at baseline and follow-up, on the Hopkins Verbal Recall measure for short-term memory and the Instrumental Activities of Daily Living (IADL) scale for executive function.

“In this cohort of community-living older men…total anticholinergic burden across medications used over a year was significantly associated with poor performance on both memory and executive tasks during the 2-year follow-up period,” they reported. This finding, the researchers note, was statistically significant even after controlling for potential confounders such as age, education, activities of daily living function, comorbidities, severity of hypertension, and use of other medications. Han and colleagues also pointed out that most of the medications that the men in the study were taking have mild to moderate anticholinergic effects and had been prescribed at doses that were not particularly high. Their study extends previous findings concerning acute cognitive impairment following recent anticholinergic exposure in older medical inpatients. Along with related research, it provides further support for the cholinergic deficit hypothesis of cognitive disorders, especially Alzheimer’s dementia.

In light of the findings, Han et al conclude, clinicians prescribing medications should watch for potential anticholinergic adverse effects associated with long-term use in older adults. That’s prudent advice. Clinicians should also consider alternatives to these medications. In many instances, newer drugs that don’t have cholinergic effects are now available.

“Polypharmacy seems a ‘rule’ rather than an exception among older persons due to their multiple comorbidities,” Dr. Han noted recently. “Therefore, careful review and proper adjustment of patients’ drug regimens in routine clinical practice—not simply dropping all anticholinergic drugs—may have a huge impact on reducing adverse anticholinergic, and other, drug events in the elderly.”