Anticholinergic burden

The cumulative exposure to multiple medicines with anticholinergic properties is known as anticholinergic burden. Older people are commonly exposed to medicines that have anticholinergic properties. Higher anticholinergic burden in older people is associated with greater risk of morbidity and mortality, longer hospital length of stay (LOS), institutionalisation, functional and cognitive decline.¹²³

Acetylcholine (Ach) functions in both the central nervous system (CNS) and the peripheral nervous system (PNS). In the CNS, cholinergic projections, from the basal forebrain to the cerebral cortex and hippocampus, support the cognitive functions of those target areas. In the PNS, Ach activates muscles and is a major neurotransmitter in the autonomic nervous system. Anticholinergic is used to refer to substances that block the action of Ach neurotransmitter at synapses in the CNS and PNS.

Medication with anticholinergic effects aid regulation of muscles in the intestines and bladder.⁸⁸ They are also used in the management of Parkinson’s disease and chronic obstructive pulmonary disease. Anticholinergic effects can however also impact on learning and memory.⁸⁸ Anticholinergic effects can be the side effect of multiple different medications that are not primarily used for their anticholinergic effect, e.g. tricyclic antidepressants and antihistamines. Therefore a large range of medication can lead to adverse anticholinergic effects including impaired cognition, increased risk of falls, functional decline, cardiovascular events, and mortality. Blurred vision, urinary retention, and constipation are known peripheral adverse effects of anticholinergic medication. Sensitivity varies across individuals and is dose-dependent.^{123,124,125,126,127}