Further Insights Into Anticholinergic Action Informed by Japanese Anticholinergic Risk Scale

Area of Science:

• Geriatric Pharmacy
• Pharmacology
• Drug Safety

Background:

• Anticholinergic burden from medications is a significant concern in older adults, linked to geriatric syndromes and cognitive dysfunction.
• Polypharmacy often contributes to the increased anticholinergic burden.
• The Japanese Anticholinergic Risk Scale (JARS) was developed to assess medication anticholinergic effects.

Purpose of the Study:

• To re-examine anticholinergic effects of drugs, focusing on discrepancies between the Yamada Classification and JARS.
• To identify drugs exhibiting "anticholinergic-like effects" beyond direct muscarinic receptor antagonism.
• To emphasize the prevalence of drugs with potential anticholinergic-like effects through literature review.

Main Methods:

• Literature review focusing on drugs with differing classifications in anticholinergic risk.
• Comparison of in vitro muscarinic receptor binding data (Yamada Classification) with clinical risk assessments (JARS).
• Analysis of potential mechanisms for "anticholinergic-like effects" not explained by direct receptor antagonism.

Main Results:

• Identified drugs with "anticholinergic-like effects" not predicted by direct muscarinic receptor antagonism.
• Highlighted discrepancies between in vitro receptor binding data and clinical anticholinergic risk scales.
• Underscored the complex nature of drug-induced anticholinergic effects.

Conclusions:

• Anticholinergic effects can arise from mechanisms beyond direct muscarinic receptor antagonism.
• Understanding "anticholinergic-like effects" is crucial for managing medication risks in the elderly.
• Further research is needed to elucidate the full spectrum of anticholinergic activity in various drugs.