A recent headline in international media warns that a common over-the-counter (OTC) medication, widely used for allergies, may increase the risk of dementia, prompting concern among health professionals and the public in Thailand and globally. Leading doctors cited in a recent report from Women’s Health Magazine are drawing attention to mounting research that connects the use of certain antihistamines—medicines typically purchased without a prescription—to a greater likelihood of future cognitive decline.
Antihistamines, such as those found in many allergy and cold remedies, are a staple in Thai households, especially as allergy rates and pollution-linked respiratory issues rise in Bangkok and other urban centers. The significance of this caution, therefore, touches everyday life for millions in the Kingdom who self-medicate with OTC drugs, often without consulting pharmacists or healthcare providers.
Multiple studies have flagged a group of antihistamines classified as “first-generation” medications—such as diphenhydramine—for their anticholinergic properties, which affect neurotransmitter activity in the brain. According to US-based neurologists quoted in Women’s Health Magazine, long-term or excessive use of these medications, particularly in older adults, appears linked with an increased risk of developing dementia. This finding aligns with a growing body of scientific literature, including major reviews from respected journals such as JAMA Internal Medicine, which found that cumulative anticholinergic use raises dementia risk by nearly 50% in some populations (JAMA Internal Medicine).
Anticholinergic medications block the action of acetylcholine, a neurotransmitter essential for learning and memory. Experts including members of global dementia research networks caution that when medications disturb acetylcholine transmission over time, especially in those already vulnerable to cognitive decline, the cumulative effect can be profound. “The sustained blocking of acetylcholine receptors may accelerate neurodegenerative changes,” said one geriatric psychiatrist from a leading medical university in the United States, as reported in recent literature (Harvard Health).
While these risks are now being widely communicated in the US and Europe, Thai medical authorities have started issuing similar advisories. Representatives from the Thai Food and Drug Administration (FDA) and leading pharmacy faculties in Bangkok emphasize that while second-generation antihistamines (such as loratadine and cetirizine) are generally safer due to less brain penetration, first-generation types remain popular due to their sedative effects and low cost. These older compounds are found in classic remedies sold across Thai pharmacies, night markets, and even local convenience stores—frequently without adequate consumer guidance.
Historically, in Thailand like elsewhere, people have relied on OTC medicines for minor ailments, viewing them as benign. Pharmacology lecturers at Chulalongkorn University have highlighted a widespread lack of awareness among consumers about the cognitive side effects of seemingly harmless pills. Anecdotes from caregivers across Bangkok’s elders’ homes increasingly mention memory problems and confusion after regular use of older antihistamines, a pattern described in regional medical journals.
With Thailand’s population rapidly ageing—the proportion of Thais over 60 is projected to double by 2040—the implications are far-reaching. Dementia already burdens thousands of families and the healthcare system. Recent data from the Department of Disease Control show that Alzheimer’s disease and other dementias are among the top ten causes of death in the country (DDC Thailand).
Medical experts recommend that elderly Thais and caregivers carefully check the ingredients of OTC medications and consult on safer alternatives if possible. “Second-generation antihistamines are much preferred, especially for seniors,” noted a senior pharmacist at Siriraj Hospital, echoing recommendations from international Alzheimer’s associations. Where sleep aids are required, non-medication approaches—including structured sleep routines, meditation, and herbal teas such as chamomile—may offer a lower-risk solution for the elderly.
With traditional Thai cultural respect for elders and strong family-centered caregiving, the new research offers a call to action for compassionate vigilance. Communities, pharmacists, and primary care physicians must actively educate patients and families about the hidden risks in the medicine cabinet, especially for older adults with allergies, colds, or insomnia. The Royal Thai Ministry of Public Health has started disseminating guideline updates through provincial hospitals and primary care networks, encouraging a shift toward both safer prescription choices and better consumer awareness (Ministry of Public Health).
Looking ahead, continued research will be crucial as Thailand seeks to balance convenience, cost, and safety in pharmaceutical regulation. Innovations in digital health records and pharmacy warnings could alert consumers to possible drug interactions and long-term side effects, designed to reduce the national dementia burden.
For readers and families in Thailand, practical steps include: checking all medication labels, consulting pharmacists for recommended products, and considering lifestyle or herbal alternatives where appropriate. Healthcare professionals should proactively update their knowledge in line with global research on cognitive health. Empowering patients with information and regular medication reviews will help ensure that “everyday medicine” truly supports lifelong well-being.