10 Unexpected Truths About Antihistamine Side Effects

2. Drowsiness and Sedation: The Sleep Connection

One of the most common side effects of antihistamines is drowsiness, a phenomenon that can be traced back to their impact on the central nervous system. The sedative properties of antihistamines are particularly pronounced in first-generation antihistamines, such as diphenhydramine and chlorpheniramine. These medications can cross the blood-brain barrier, leading to significant central nervous system depression and sedation. The sedative effect, while beneficial for those seeking relief from insomnia, can be problematic for individuals who need to remain alert, such as drivers or those operating heavy machinery. The drowsiness can impair cognitive function, reaction times, and overall alertness, posing safety risks. As we delve deeper into this side effect, it becomes evident that the choice of antihistamine—whether first or second generation—can significantly influence the severity of drowsiness and its impact on daily life.