Daijiworld Media Network - New Delhi

New Delhi, Oct 22: Common anti-allergy medications, particularly first-generation antihistamines, may significantly increase the risk of delirium in older adults, raising fresh concerns about their long-term impact on brain health. A new study published in the Journal of the American Geriatrics Society suggests that these widely used drugs could contribute to cognitive decline and possibly increase dementia risk in the elderly.

Researchers from the University of Toronto examined data from over 328,000 patients aged 65 and above who were admitted to 17 hospitals in Ontario between 2015 and 2022. They focused on the prescribing patterns of 755 physicians and found a worrying trend: patients under the care of doctors who frequently prescribed sedating, first-generation antihistamines—such as diphenhydramine—had a 41% higher chance of experiencing delirium compared to those treated by physicians who rarely used such medications.

Delirium, a severe and sudden state of confusion, is already common in hospitalised older adults—affecting up to half of them—and is strongly linked to increased mortality and long-term cognitive issues. The study revealed that nearly 35% of the patients experienced delirium during their hospital stay.

First-generation antihistamines, although effective for conditions like hives and severe allergic reactions, are often misused for other types of itching or minor conditions where safer, non-sedating alternatives exist. The research team emphasised that these older drugs do not offer superior relief compared to modern antihistamines but do carry significantly greater risks—particularly for older adults.

Lead author Dr. Aaron M. Drucker urged greater caution, stating, "We hope our study raises awareness among hospitalists that sedating antihistamines can be harmful, and should be prescribed with caution."

With dementia cases projected to triple globally by 2050—from 57 million to over 152 million—this research highlights the urgent need to re-evaluate the use of medications that may exacerbate or contribute to cognitive decline in ageing populations.