Many people rely on everyday medications to treat health problems like allergies, high blood pressure, depression, and motion sickness.
These drugs are widely used and often trusted because they’ve been around for years. But a new study from the University of California, San Diego, suggests that some of these common medicines might be quietly affecting our brain—especially in older adults or those at risk for Alzheimer’s disease.
The research focused on a group of drugs known as anticholinergics. These medicines work by blocking a chemical in the body called acetylcholine. Acetylcholine plays a key role in memory, learning, muscle movement, and heart function. Blocking this chemical may help with some illnesses, but it might also slowly harm how the brain works.
To explore this, researchers followed 688 older adults for up to 10 years. The average age of the participants was 74, and none of them had memory or thinking problems at the beginning of the study.
The scientists asked each person whether they had taken any anticholinergic medications at least once a week for more than six months. Every year, the researchers tested the participants’ memory and thinking skills to look for changes.
About one in three people had used anticholinergic drugs. On average, these people were taking nearly five different medications. Common examples included metoprolol and atenolol for high blood pressure, loratadine for allergies, and bupropion for depression.
What they discovered was surprising. People who used at least one anticholinergic drug were 47% more likely to develop mild cognitive impairment (MCI) than those who didn’t take the drugs.
MCI is a condition where a person’s memory and thinking ability are weaker than normal for their age. It’s not the same as dementia, but it can lead to dementia or Alzheimer’s disease over time.
The risks were even greater for people who were already at risk for Alzheimer’s. For those who had signs of Alzheimer’s in their spinal fluid, taking anticholinergic drugs made them four times more likely to develop memory problems. And those who had a gene linked to Alzheimer’s were 2.5 times more likely to show memory decline if they used these medications.
This study raises important questions about how these common drugs might affect brain health. Many people take these medicines without realizing they could have long-term effects on memory. The researchers suggest that older adults should speak with their doctors about their medications and ask whether safer alternatives are available.
This study also adds to a growing body of research showing that medicines can sometimes have side effects in areas we don’t expect. A drug meant to help with one health issue might create new problems elsewhere—like with the brain.
If you or someone you care about is using medications for allergies, blood pressure, or depression, and you’re worried about memory loss, it’s a good idea to talk to a healthcare professional. There may be better choices that protect your brain while still helping with your condition.
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This research was led by Dr. Lisa Delano-Wood and published in the journal Neurology.
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