Your favorite cold medicine could be shrinking your brain. A new study reveals that drugs used to treat colds and a range of other common health issues, including allergies, heartburn, hypertension, insomnia, and depression, may erode gray matter and increase the risk for dementia and other cognitive problems in older adults.
Over-the-counter and prescription medications, such as Tylenol PM, Benadryl, Claritin, Dimetapp, Paxil, Xanax, Zyrtec, Lasix, and Coumadin, belong to a class of drugs known as anticholinergics. They work by blocking acetylcholine, a chemical that transmits electrical impulses between nerve cells.
Using PET and MRI scans, researchers from Indiana University School of Medicine examined the brain structure and metabolism of 451 people with an average age of 73. The study found those taking anticholinergic drugs had smaller brains and lower levels of glucose metabolism, particularly in the hippocampus—a brain region involved with memory that is vulnerable to earlystage Alzheimer’s disease. People on anticholinergics also performed less well on tests measuring short-term memory and executive functions, including planning, verbal reasoning, and problem solving.
Alzheimer’s patients are deficient in acetylcholine, which is why, the researchers warn, these drugs could trigger or worsen the disease. If taking them is absolutely necessary, study author Shannon Risacher tells Time.com, “I’d suggest that doctors monitor medications and their effects, and use the lowest dose that’s effective.”