Nikhil Prasad Fact checked by:Thailand Medical News Team Oct 23, 2025 14 hours, 11 minutes ago
Medical News: Older Adults Face Hidden Dangers from Common Antihistamines
A large-scale study by researchers from the University of Toronto and Women’s College Hospital in Canada has uncovered a troubling link between the use of common antihistamines and delirium in older hospital patients. These widely used drugs, especially first-generation types like diphenhydramine (Benadryl), are often prescribed for allergies, hives, or sleep problems—but they may cause serious confusion and cognitive issues among elderly patients.
According to this
Medical News report, the research analyzed medical records from over 328,000 hospitalized adults aged 65 and older across 17 hospitals in Ontario, Canada, from 2015 to 2022. The data showed that about 35 percent of older patients experienced delirium during their hospital stay. However, those admitted to physicians who frequently prescribed first-generation antihistamines had a 41 percent higher chance of developing delirium compared to patients treated by doctors who prescribed these drugs rarely.
How Antihistamines Affect the Aging Brain
First-generation antihistamines easily cross the blood–brain barrier and interfere with brain activity, causing drowsiness, confusion, and memory loss. The study revealed that even a 1 percent increase in a doctor’s use of these sedating antihistamines raised the risk of delirium in their older patients by 8 percent. Researchers warned that while such medications are useful for allergic reactions, they may be inappropriately prescribed for conditions like itching or insomnia, where safer non-sedating alternatives would work just as well.
Dr. Aaron M. Drucker, senior author of the study and dermatologist at the University of Toronto and Women’s College Hospital, urged doctors to reconsider their prescribing habits. “Sedating antihistamines can be harmful, and their risks outweigh benefits in older adults,” he said, emphasizing the importance of using second-generation antihistamines that do not cause such mental side effects.
Preventable and Often Overlooked
Delirium is not a temporary inconvenience—it is a serious and potentially fatal condition that can lead to long-term memory problems, increased hospital stays, and even higher mortality rates. The researchers suggest that physician prescribing habits are a modifiable risk factor, meaning hospitals can reduce delirium rates simply by switching to safer medications and updating treatment guidelines.
Conclusions
This important study highlights the dangers of outdated drug practices in hospitals. Common sedating antihistamines, though widely available, may pose a significant threat to elderly patients by triggering delirium and accelerating cognitive decline. Greater awareness, education, and policy changes could help protect vulnerable patients and improve recovery outcomes.
The study findings were published in the peer-reviewed Journal of the American Geriatrics Society.
https://agsj
ournals.onlinelibrary.wiley.com/doi/10.1111/jgs.70121
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