The anticholinergic class of drugs, commonly prescribed to older people, may be linked to an increased risk of dementia when used often and in a strong formulation.

Anticholinergic drugs are a class of drugs that block the acetylcholine, which is used as a neurotransmitter – a message from nerve cells to other cells.

Acetylcholine is important for everyday function, but it can be useful to block it because it influences the movement of certain muscles that can become an issue in conditions like overactive bladder, chronic obstructive pulmonary disease with narrowed airways and the muscle stiffness of Parkinson’s disease.

While anticholinergics are commonly used by older Australians, a growing body of evidence suggests they may be linked to a higher incidence of dementia.

In a new British study, researchers looked at the prescription of anticholinergic drugs to more than 280,000 people who were over the age of 55. None of these people had a diagnosis of dementia when the research started, but during the 12 years they were followed up, about 20 per cent did develop dementia. The researchers evaluated the total exposure of each person in the study to anticholinergic drugs over time.

In this way, they were able to stratify people into groups by their drug exposure, and see whether higher amounts of drug exposure led to a higher incidence of dementia. They controlled for other factors that could have influenced a dementia diagnosis – like heart disease, diabetes and smoking.

They found a 50 per cent increased risk of dementia among people who used an anticholinergic drug for several years.

The association was stronger for certain classes of anticholinergics – medications like antidepressants and anti-epileptics , versus antihistamines and muscle relaxants, which are considered milder anticholinergics.

Implications

If you take anticholinergic drugs, these results aren’t a reason to stress. But they may provide an opportunity for you to speak to your general practitioner about your drug prescriptions, and ask about the benefits and risks you get from your medications.

Last Reviewed: 03/04/2020

© Norman Swan Medical Communications.



References

For reference: Coupland, et al (2019). Anticholinergic Drug Exposure and the Risk of Dementia A Nested Case-Control Study. JAMA Internal Medicine doi: 10.1001/jamainternmed.2019.0677.

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