Lapatinib Products | Cleanchem - Lapatinib is a dual tyrosine kinase inhibitor targeting both HER2 and EGFR receptors, used primarily in the treatment of HER2-positive breast cancer. It interferes with cellular signaling involved in tumor growth and proliferation. Lapatinib is often used in combination with capecitabine or letrozole for advanced or metastatic cases. Common side effects include diarrhea and rash, and cardiac function monitoring is advised.