Antimuscarinic Anticholinergic Medications in Parkinson Disease: To Prescribe or Deprescribe?

Abstract

The relative importance of antimuscarinic anticholinergic medications for Parkinson's disease (PD) declined after the introduction of levodopa, such that anticholinergic medications are now much more likely to be prescribed for clinical indications other than parkinsonism. Recent studies have found an association between anticholinergic medication exposure and future risk of dementia in older individuals and those with PD. These findings provide a further reason to avoid the use of anticholinergic medications to treat motor symptoms of PD. More importantly, they raise the question of whether one of the goals of PD treatment should be to deprescribe all medications with anticholinergic properties, regardless of their indication, to reduce dementia risk. In this review, we discuss the use of anticholinergic medications in PD, the evidence supporting the association between anticholinergic medications and future dementia risk, and the potential implications of these findings for clinical care in PD.

Keywords: Parkinson's disease; Parkinson's disease dementia; anticholinergic medications; deprescribing; neurotoxicity.

FIG. 1

The role of broadly brain expressed CYP450 enzymes on anticholinergic drug metabolism. This figure displays the number of anticholinergic medications included in the Anticholinergic Cognitive Burden scale that are metabolized by each cytochrome P450 enzyme.