Cognitive Risks of Anticholinergics in the Elderly

Philip Gerretsen; Bruce G Pollock


Aging Health. 2013;9(2):159-166. 

In This Article

Abstract and Introduction


Many drugs commonly prescribed to the elderly have anticholinergic properties. Due to the current clinical use of drugs with mild-to-modest anticholinergic activity, the clinical manifestations of anticholinergic toxicity are likely to be nonspecific (e.g., cognitive impairment) and reflect the effects of cumulative anticholinergic burden. Age-associated physiological and pharmacokinetic changes increase anticholinergic drug effects in later life. Those with cognitive impairment and neurodegeneration are particularly susceptible to anticholinergic toxicity. Recent findings suggest that chronic anticholinergic burden may hasten or contribute to a neurodegenerative process. APOE ε4 carrier status may be a genetic risk factor for vulnerability to negative anticholinergic effects. There is no clinically available laboratory test to assess anticholinergic levels. Clinicians need to be cognizant of anticholinergic risks in later life. The use of clinical scales (e.g., Anticholinergic Drug Scale) and consensus guidelines (e.g., Revised Beers Criteria) may be helpful.


Many drugs commonly prescribed to the elderly have anticholinergic properties, which can contribute to serious anticholinergic adverse effects, including cognitive impairment[1,2] and delirium.[3] Drugs with anticholinergic properties exist in many forms for a variety of indications, including over-the-counter cold and flu remedies, sleep aids and antiemetics; urinary incontinence and respiratory drugs; and antidepressants, antipsychotics and antiparkinsonian agents.[4]

The prevalence of use of drugs with anticholinergic properties depends on the population being studied. For example, in a large study of nursing home residents, close to half of those prescribed acetylcholinesterase inhibitors were also prescribed drugs with anticholinergic effects;[5] whereas, in a random community sample, 90% of study participants had detectable levels of anticholinergic activity.[6]

Significant pharmacological gains have been made to minimize or eliminate unwanted anticholinergic effects. For example, selective serotonin reuptake inhibitors have replaced the highly anticholinergic tricyclic antidepressants. These positive advances in the form of less potent anticholinergic drugs may contribute to reduced awareness among clinicians of possible adverse effects. This places the elderly at risk of insidious anticholinergic accumulation from drugs with minimal-to-modest anticholinergic activity.

The aim of this work was not intended to be a systematic review of the literature, but rather a clinically relevant update. Our intent is to focus on the bidirectional relationship between normal and abnormal aging of the cholinergic system and the cognitive risks of anticholinergics in later life.[4,7]