Summary: commonly-used prescription and over-the-counter drugs may contribute to memory loss in older people, particularly if taken for long periods of time.
Results of a recent study by scientists at Yale University suggest that long term use of some prescription and over-the-counter medicines contributes to memory loss in older people. Previous studies, including one by French researchers, had also shown a connection between these medicines and memory loss. The Yale study, which quantified the effects of using multiple anticholinergic medicines over time, confirmed this connection. For study participants (544 men 65 and older), cumulative exposure to these medicines over a year’s time was associated with lower scores on tests of short term memory and executive function. The study authors believe that the medicines have a similar effect on women.
What is an anticholinergic medicine?
Anticholinergic medicines reduce the function of acetylcholine, a chemical that carries information among brain cells. Lower levels of acetylcholine are thought to contribute to memory loss. In fact, the cholinesterase inhibitors often prescribed to treat the symptoms of memory loss are aimed at maintaining normal levels of this chemical.
“Medications with anticholinergic effects include selected drugs used to treat a range of health conditions, such as those prescribed for urinary incontinence, sleep, psychiatric conditions, gastrointestinal cramps, and allergies,” says study co-author Dr. Ling Han of Yale University’s Department of Internal Medicine. While many of these medicines are available by prescription only, anticholinergic allergy and sleep medicines (Benadryl, Sominex, Tylenol PM and Nytol, for example) are available over-the-counter.
Older people are more vulnerable
The effects of these drugs are known to be stronger in older people. “Several researchers have discussed the higher susceptibility of older adults to adverse anticholinergic drug effects because of increased sensitivity to drugs and also because of reduced metabolism of these drugs due to physiological changes that occur with aging,” says Dr. Han.
In addition, many older people take a combination of prescription and over-the-counter drugs and so are more likely to be exposed to drugs with anticholinergic effects. One study found that as many as half of people with dementia are taking this type of medicine, perhaps worsening their cognitive problems.
Are the effects reversible?
The Yale study was not designed to answer the question of whether the cognitive effects of these drugs are reversible. “However, based on our clinical experience and knowledge of pharmacology of anticholinergic drugs, these effects are likely reversible for many patients,” says co-author Dr. Joseph Agostini, Assistant Professor of Medicine at Yale.
Ask your doctor to review your medicines
Wondering if any of your medicines are anticholinergic? Suspect that your medicines are contributing to memory loss? Check with your doctor. “Patients should avoid stopping medications, even those with known anticholinergic effects, without consulting their trusted physician first,” says Dr. Agostini. “Having a doctor review your medication regimen should be part of a comprehensive evaluation of any suspected cognitive change.”
“All medications have possible adverse effects,” he explains. “For those with memory impairment or diagnosed dementia, the decision to take a medication with possible or known anticholinergic effects should be evaluated in the context of the overall benefit-risk balance. There are no clear guidelines to guide decision-making, but rather clinical judgment on the part of the physician and discussion with the patient. There may be good reasons to prescribe an anticholinergic medication in an older patient with dementia, so the decision is more nuanced than stating that these medications should never be prescribed. In general, you should take medications for as long as there is an appropriate indication, you and your physician are re-evaluating the risk-benefit relationship on a regular basis, and also monitoring for adverse effects over time.”
More research and attention needed
“As our population ages and develops conditions such as dementia and other cognitive disorders,” says Dr. Han, “it is increasingly necessary to be able to understand all the effects of medications—including both the hoped-for beneficial effects but also the potential harmful effects. This type of research will hopefully stimulate further dialogue and studies to facilitate better ways to help patients and physicians choose and take the best combination of medications, especially when patients are already taking multiple different medications for their acute and chronic conditions.”
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