Cetirizine hydrochloride is commonly used to treat symptoms of allergies, such as sneezing, runny nose, itchy nose or throat, and itchy, red or watery eyes, according to MedlinePlus. Cetirizine also relieves redness and itching caused by hives, but it does not prevent hives or other skin allergies.
Cetirizine, sold under the brand name Zyrtec, is an antihistamine that works by stopping the action of histamine, which causes allergic responses in the body, explains MedlinePlus. Cetirizine is typically taken once a day and is available in multiple forms, including a tablet, chewable tablet, extended release tablet and liquid. Patients who take other medications, specifically antidepressants, anxiety medication, seizure medication, sleeping pills or theophylline, should consult with a doctor or pharmacist before taking cetirizine.
Cetirizine may cause side effects, including stomach pain, dry mouth, diarrhea and vomiting. Drowsiness and excessive fatigue may also occur, so it's best for patients to avoid driving or operating machinery until they know how cetirizine affects them, states MedlinePlus. Reporting these side effects to a doctor is recommended if they are severe or persistent. Patients should seek emergency medical attention if they experience symptoms of a life-threatening allergic reaction while taking cetirizine, such as difficulty breathing or swallowing, swelling in or around the mouth, wheezing, dizziness or loss of consciousness.