Some recent medical studies have suggested that overuse of antihistamine medication may result in Alzheimer’s disease. Only some of the older non-sedating antihistamines were mentioned in the study.
Some older (sedating) antihistamines such as chlorphenamine and diphenhydramine cross into the brain and can cause drowsiness and are even used as OTC “sleeping pills”. Newer once-daily non-sedating antihistamines do not cross this blood/brain barrier and thus have no anticholinergic effects and are unlikely to be implicated in Alzheimer’s disease.
