What is a known side effect of antihistamines that the nurse should educate the patient about?

Drowsiness is a common side effect of antihistamines, particularly first-generation antihistamines. These medications cross the blood-brain barrier and can interfere with the central nervous system, leading to sedation and drowsiness. This effect can be particularly significant when the antihistamines are taken in higher doses or in combination with other substances that also cause sedation, such as alcohol or certain pain medications.

Educating patients about the potential for drowsiness is crucial, as it can affect their daily activities, including driving or operating machinery. Additionally, patients should be advised about how to manage this side effect, such as taking the medication at bedtime if sedation is a concern. Understanding this side effect helps patients make informed decisions about their medication regimen and lifestyle adjustments to ensure their safety and well-being.