Newcastle, UK—Anticholinergic medications are often used to treat both motor and nonmotor symptoms in Parkinson’s disease patients. That has raised concerns because of recent evidence linking the drugs to a greater risk of dementia, such as Alzheimer's disease (AD), in those who use the drugs regularly, according to a new study.

Background information in the short communication, published recently in the Journal of Parkinson's Disease, notes that anticholinergics are widely used in older adults to treat bladder dysfunction, mood, and pain, and many of them are available without prescription.

A study team led by Newcastle University researchers determined, however, that the cognitive performance of PD patients taking anticholinergic medications showed no difference from those not on the drugs.

“This is the first study to explore an association between anticholinergic burden and mild cognitive impairment (MCI) in PD participants, and is timely given recent research demonstrating cumulative anticholinergic burden and risk of AD in the general population,” explained principal investigator David J. Burn, MD, director of the Institute of

Neuroscience and Professor of Movement Disorder Neurology at Newcastle University, UK. “Our assessment will help determine whether patients prescribed medication with anticholinergic activity are more likely to develop dementia, and hence allow early targeted intervention to reduce future risk.”

For the study, researchers used data from the Incidence of Cognitive Impairment in Cohorts with Longitudinal Evaluation–Parkinson's Disease study (ICICLE-PD), a twin center longitudinal observational study of the anatomical, biochemical, and genotypic mechanisms underlying the evolution of persons developing dementia related to Parkinson’s disease (PDD).

Included in the study were 195 PD patients and 84 control patients. Detailed medication history, including OTC drugs, was evaluated according to the Anticholinergic Drug Scale (ADS) for the PD patients. Each drug was classified on a scale from 0 to 3 according to no (0), mild (1), moderate (2), or high (3) anticholinergic activity.

In addition, total usage from baseline to 18-month follow up was used to produce a total burden score. Those with ADS scores greater than or equal to 1 were in the PD+ADS group while those with ADS scores equal to 0 were designated PD-ADS.

Comparison of the 83 PD+ADS and 112 PD-ADS participants revealed no differences in global cognition or assessments of attention, memory, and executive function after 18 months. Furthermore, the proportion of mild cognitive impairment was similar in those with and without anticholinergic drug use, according to the study.

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