Histasys LM Tablet contains Levocetirizine 5mg and Montelukast 10mg, combining the efficacy of an antihistamine and a leukotriene receptor antagonist to provide comprehensive relief from allergic conditions. Levocetirizine is a selective, non-sedating H1 antihistamine that effectively reduces symptoms such as sneezing, rhinorrhea, nasal itching, and urticaria by inhibiting peripheral histamine receptors. Montelukast acts by blocking leukotriene D4 receptors in the airways, thereby reducing inflammation, bronchoconstriction, and mucus production associated with allergic rhinitis and asthma. This combination is indicated for the management of seasonal and perennial allergic rhinitis, chronic idiopathic urticaria, and as adjunct therapy in mild to moderate asthma. Histasys LM Tablet offers improved symptom control by targeting multiple pathways in the allergic response, enhancing patient compliance through once-daily dosing. It is generally well tolerated, with adverse effects including headache, fatigue, and gastrointestinal discomfort being infrequent and mild. Caution is advised in patients with hepatic impairment, and it is contraindicated in individuals with known hypersensitivity to either component. Consultation with a healthcare professional is recommended before initiating therapy to ensure appropriate use and monitoring.