Could anticholinergics accelerate ALS progression? A critical perspective on drug safety and disease vulnerability

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with limited treatment options and diverse symptoms necessitating active management. Anticholinergic medications are frequently used in ALS care, particularly for sialorrhea and mood disturbances. Their cumulative effects, termed anticholinergic burden, may pose underrecognized risks in this neurologically vulnerable population. This review highlights a plausible safety signal and outlines priorities for future research.

This narrative review synthesizes evidence from non-ALS populations reporting associations between higher anticholinergic burden and cognitive decline, respiratory complications, functional deterioration, and mortality. Evidence was identified through targeted PubMed/MEDLINE and Embase searches with reference chaining, emphasizing recent and seminal studies. Mechanistic overlap with ALS pathophysiology, including neuromuscular junction disruption, impaired cholinergic signaling, and neuroinflammation, supports biological plausibility for harm. Current ALS guidelines do not address cumulative anticholinergic exposure, leaving clinicians without a framework for evaluating risk or deprescribing.

This article proposes a testable hypothesis that anticholinergic burden may represent a clinically relevant yet unmeasured risk factor in ALS. Emerging pharmacoepidemiologic methods and validated burden tools offer approaches to quantify exposure and evaluate relationships with ALS outcomes, supporting safer symptomatic management. Prioritizing longitudinal studies and integrating burden assessment into multidisciplinary care may help clarify risk.