A commonly-used over-the-counter medication<\/a> that can provide allergy and cold relief or serve as sleep aids may increase a person\u2019s risk of dementia<\/a>. <\/p>\n Antihistamines work to block the chemical histamine<\/a>, which causes uncomfortable allergy symptoms. However, what kind of antihistamine you\u2019re taking can make a big difference to your long-term health. <\/p>\n There are two main types of antihistamines on the market: first-generation and second-generation<\/a>.<\/p>\n Physicians say that these \u201cfirst-generation\u201d antihistamines<\/a> are less safe because they more easily cross your blood-brain barrier into the central nervous system, causing drowsiness. The second-generation antihistamines, meanwhile, do not. <\/p>\n open image in gallery<\/p>\n Commonly-used drugs to provide allergy relief may also come with a risk of dementia when taken long-term. Patients should know which kind to take before they make their next purchase (Getty Images\/iStock)<\/p>\n “People sometimes assume these medications must be harmless because they are sold over the counter, but if you use them too often or for too long, they can mess with your thinking, make you groggy during the day, and possibly lead to long-term problems,” Dr. Pamela Tambini, an internal medicine physician and medical director at Engage Wellness, recently told Women\u2019s Health<\/a>.<\/p>\n The first-generation antihistamines specifically target a key brain chemical involved in memory that is called acetylcholine. Because of their design, they have a long-term impact on our brain\u2019s health. That negative impact has been documented for a few years \u2014 but may not be something on your mind when you need relief.<\/p>\n Frequent use of these first-generation sleep medications has been tied to an increased risk of the chronic disease in older adults, according to a study published in the Journal of Alzheimer’s Disease<\/a> in 2023. <\/p>\n A 2024 study in the Journal of Allergy and Clinical Immunology<\/a> also said there was some risk associated with second-generation antihistamines, but it was lower. A study published this year in the World Allergy Organization Journal<\/a> suggests that people should avoid taking Benadryl<\/a>.<\/p>\n![\"Commonly-used](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/05\/iStock-584201758.jpeg\")
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