What side effect should a nurse check for in a client taking cetirizine hydrochloride (Zyrtec)?

Cetirizine hydrochloride, commonly known as Zyrtec, is an antihistamine that is often used to alleviate allergy symptoms such as sneezing, runny nose, and hives. One of the notable side effects of cetirizine is drowsiness. This occurs because cetirizine can cross the blood-brain barrier, which may lead to sedation and increased sleepiness in some individuals.

When taken, cetirizine works by blocking histamine receptors, which can have a calming effect on the central nervous system. Patients are typically advised to be cautious when operating machinery or driving until they know how the medication affects them. Monitoring for drowsiness is crucial for patient safety, particularly if the patient is taking other medications that may also cause sedation.

The other potential side effects, while they may occur with other medications, are not the primary concerns with cetirizine use. For instance, excitability may be seen in some rare cases, particularly in children or when overdosed, but it is not a common effect. Therefore, vigilant observation for drowsiness in patients on cetirizine is recommended to manage this side effect effectively.