Levosiz Tablet contains Levocetirizine 5mg, a third-generation non-sedating antihistamine used primarily for the relief of allergic symptoms. Levocetirizine is the active enantiomer of cetirizine and acts as a selective antagonist of peripheral H1 histamine receptors, thereby inhibiting the effects of histamine, a key mediator in allergic reactions. This medication is indicated for the treatment of allergic rhinitis, including seasonal and perennial types, as well as chronic idiopathic urticaria characterized by itching and hives. Levosiz offers rapid onset of action and provides effective symptom control with minimal sedative effects compared to first-generation antihistamines. It is generally well tolerated, with common adverse effects including mild headache, dry mouth, and fatigue. The recommended adult dosage is one 5mg tablet once daily, preferably in the evening, with dose adjustment advised in patients with renal impairment. Levosiz should be used cautiously in individuals with known hypersensitivity to levocetirizine or related compounds. It is contraindicated during pregnancy and lactation unless clearly necessary. As with all medications, patients should consult their healthcare provider before initiating therapy to ensure appropriate use and to discuss potential drug interactions.