Medically reviewed by Daniel More, MDMedically reviewed by Daniel More, MD Common side effects of Zyrtec (cetirizine) can include drowsiness, fatigue, dry mouth, sore throat, and dizziness.

As with other drugs, cetirizine can cause side effects, such as drowsiness and sore throat. If you are not able to tolerate side effects from cetirizine, talk with your doctor or pharmacist.

As an antihistamine, Zyrtec works by blocking the action of histamine, a substance in the body that contributes to symptoms ...