Levocetirizine tablets should not be taken twice a day. Levocetirizine tablets refer to levocetirizine hydrochloride tablets. This medication is an antihistamine used to treat allergy symptoms caused by seasonal allergic rhinitis, perennial allergic rhinitis, chronic idiopathic urticaria, and other conditions. The drug should be taken only once a day as one tablet for adults and children aged 6 years and above, and it is not recommended to take it twice a day as it may cause some adverse reactions. The common adverse effects of the drug are headache, drowsiness, dry mouth, fatigue, debility, abdominal pain and other discomforts that may occur in other patients after taking the drug. Contraindications to the use of the drug are: allergy to any component of the product or allergy to piperazine derivatives, creatinine clearance <10ml/min patients with advanced kidney disease, with special genetic diseases such as primary intestinal lactase deficiency or glucose-lactose malabsorption patients are prohibited. In addition the drug should not be used by children under 6 years of age, pregnant and lactating women. Levocetirizine tablets should be used under the guidance of a professional doctor, and should not be used blindly on its own to avoid adverse reactions.