A comprehensive exploration of adverse reactions to lapatinib: a disproportionate analysis based on the FAERS database

Lapatinib, an FDA-approved tyrosine kinase inhibitor, treats HER2+ advanced/metastatic breast cancer. This study comprehensively analyzed its adverse reaction profile using FDA Adverse Event Reporting System (FAERS) to guide clinical use. Adverse event (AE) reports for lapatinib from the second quarter of 2007 to the second quarter of 2024 in FAERS were analyzed using Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Multi-item Gamma Poisson Shrinkage (MGPS) and Bayesian Confidence Propagation Neural Network (BCPNN) to identify AE signals. Among 8300 AE reports, females (91.47%) and ages 40–59.9 (33.71%) were predominant. 20 system organ classifications (SOCs) were affected, with gastrointestinal disorders (ROR = 3.46) and skin disorders (ROR = 2.47) most significant. Based on the PT level, a total of 111 PTs were analyzed that met the four algorithms, including typical AEs such as diarrhea (n = 3410), vomiting (n = 856), and rash (n = 856), as well as some rare AEs that were not prompted by the drug inserts, such as neutropenia (n = 252), pericardial effusion (n = 43), lymphedema (n = 20). The majority of lapatinib-associated AEs had onset within 30 days (51%). Lapatinib has a generally favorable safety profile, but gastrointestinal toxicity and dermatotoxicity require close monitoring to prevent serious AEs.