New research has found a link between long-term use of high dose anticholinergic drugs and a higher risk of dementia in older adults.
The new study, published in the journal Aging, highlights the importance of continuing to examine medication use and effects for all conditions as we age.
Anticholinergic agents work by blocking the neurotransmitter acetylcholine and are integral to many different medications—both prescription and over-the-counter. Some conditions commonly treated with anticholinergics include overactive bladder, seasonal allergies, insomnia and depression. Medications with these properties are used by between eight and 37 per cent of older adults.
Although previous studies have shown these medicines may be associated with increased risk for cognitive impairment, this study went further.
Researchers at the University of Washington conducted a large-scale study of older adults to determine whether cumulative anticholinergic use affected the onset of dementia in this population.
In this study, researchers analyzed 10 years of pharmacy dispensing data for 3,400 people aged 65 and older with no history of dementia. Individuals taking daily anticholinergics for more than three years were at greater risk of developing dementia than those who didn’t use these medications long term.
Tricyclic antidepressants, first-generation antihistamines and antimuscarinics for bladder control were the medications examined in this study.
These results are a good reminder of the need to assess medication use on a regular basis. Health care professionals should be asking why a certain medication is being used over the long term and evaluating its likely effects. When patients are taking a medication on a long-term basis, it is wise to periodically test for effects on cognitive function or other potential side effects.
With these medications in particular, health care professionals should educate patients of potential risks and make an effort to minimize their use when possible. In many cases such as with antidepressants and sleep medications, there may be alternative medicines available that do not use anticholinergic agents and may be a better treatment option.
Ongoing research and the development of newer medications for many common disorders will also help to reduce negative effects going forward.