Millions of people take medications every day to manage common health problems such as allergies, depression, high blood pressure, motion sickness, and bladder issues.
These medicines are often considered safe because many of them have been used for years and are regularly prescribed by doctors.
However, new research suggests that some of these commonly used drugs may have an unexpected effect on the brain, especially in older adults.
Researchers at the University of California, San Diego, found that certain medications known as anticholinergic drugs may increase the risk of memory problems and cognitive decline. The findings are especially concerning for people who are already at higher risk of Alzheimer’s disease.
Anticholinergic drugs work by blocking a chemical messenger in the body called acetylcholine. This chemical plays many important roles, including helping control muscle movement, digestion, heart rate, and communication between nerve cells.
Acetylcholine is also extremely important for learning and memory. The brain relies on it to process information and form new memories. When anticholinergic drugs block this chemical, they may relieve certain symptoms, but they can also interfere with normal brain function.
Doctors prescribe these drugs for a wide range of conditions. Some are used for allergies, nausea, depression, overactive bladder, high blood pressure, and sleep problems. Because they are so common, many people may not realize they are taking medicines with anticholinergic effects.
In the new study, researchers followed 688 older adults with an average age of about 74 years. At the beginning of the study, none of the participants showed signs of memory or thinking problems.
The researchers asked participants whether they had been taking anticholinergic medications at least once a week for longer than six months. The team then monitored the participants’ memory and thinking abilities every year for up to 10 years.
About one-third of the participants reported using anticholinergic drugs. On average, these individuals were taking nearly five different medications with anticholinergic effects.
Some of the most commonly used medications included metoprolol and atenolol for high blood pressure, loratadine for allergies, and bupropion for depression.
When researchers examined the long-term results, they found a clear and troubling pattern.
People who used at least one anticholinergic medication were 47% more likely to develop mild cognitive impairment, also known as MCI, compared to people who did not use these drugs.
Mild cognitive impairment is a condition where people experience more memory and thinking problems than would normally be expected for their age. While some people remain stable, others may eventually progress to dementia or Alzheimer’s disease.
The risks became even more serious for people who already showed biological signs linked to Alzheimer’s disease.
Some participants had certain markers in their spinal fluid that suggested early Alzheimer’s-related changes in the brain. Among these individuals, those who used anticholinergic drugs were four times more likely to develop memory and thinking problems.
The researchers also studied people who carried genes associated with a higher risk of Alzheimer’s disease. These individuals were found to be 2.5 times more likely to experience cognitive decline if they used anticholinergic medications.
The findings suggest that these medicines may speed up memory decline in people who are already vulnerable.
Scientists say this is concerning because anticholinergic drugs are extremely common, and many people take them for years without considering their possible effects on brain health.
In some cases, older adults may be taking several medications with anticholinergic effects at the same time, which could further increase the risk.
Researchers believe the study highlights the importance of reviewing medications carefully as people age. Doctors and patients may need to weigh the benefits of symptom relief against the possible long-term risks to memory and thinking abilities.
The researchers are not telling people to suddenly stop taking their medications. Instead, they encourage patients to talk with their doctors before making any changes.
There may be safer alternatives available for some conditions. For example, newer medications or non-drug treatments may help manage allergies, depression, or blood pressure without affecting the brain in the same way.
The study also adds to a growing body of research suggesting that some medications can have unexpected effects on cognitive health. As scientists continue learning more about Alzheimer’s disease and brain aging, they are paying closer attention to how commonly used drugs may influence memory over time.
Experts say older adults should regularly review all their medications with healthcare providers, especially if they notice increasing forgetfulness, confusion, or concentration problems.
Simple medication reviews may help identify drugs that could potentially affect brain function and allow doctors to recommend safer options when appropriate.
The research was led by Lisa Delano-Wood and published in the journal Neurology.
In the end, the study serves as an important reminder that medications can have both benefits and risks. Medicines that help one part of the body may sometimes affect another part in unexpected ways.
Being informed, asking questions, and working closely with healthcare professionals may help people protect both their physical health and their memory as they grow older.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
For more health information, please see recent studies about Choline deficiency linked to Alzheimer’s disease, and what to eat (and avoid) for dementia prevention.
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