Libset Tablet contains Lapatinib 250 mg, a tyrosine kinase inhibitor used primarily in the treatment of advanced or metastatic breast cancer that overexpresses the human epidermal growth factor receptor 2 (HER2). Lapatinib acts by inhibiting the intracellular tyrosine kinase domains of both HER2 and epidermal growth factor receptor (EGFR), thereby blocking downstream signaling pathways involved in tumor cell proliferation and survival. This targeted therapy is indicated for use in combination with other agents, such as capecitabine, or as monotherapy in patients who have received prior treatment including anthracyclines, taxanes, and trastuzumab. Libset Tablet is administered orally, with dosing individualized based on clinical response and tolerability. Common adverse effects include diarrhea, rash, nausea, fatigue, and hepatotoxicity, necessitating regular monitoring of liver function tests during treatment. Caution is advised in patients with pre-existing cardiac conditions due to the potential risk of decreased left ventricular ejection fraction. Libset should be used under strict medical supervision, with periodic assessment to evaluate therapeutic efficacy and adverse reactions. It is contraindicated in patients with known hypersensitivity to Lapatinib or any of the tablet excipients. This medication should be stored at controlled room temperature, away from moisture and light.