Kim MK, et al. - In patients with non-small cell lung cancer (NSCLC) and pancreatic cancer, researchers examined the link between erlotinib-induced hepatotoxicity and factors such as concomitant medications. They retrospectively reviewed data for these patients, including sex, age, body weight, height, body surface area, underlying disease, Eastern Cooperative Oncology Group Performance Status, smoking history, erlotinib dose, epidermal growth factor receptor mutation, and concomitant drugs. The factors that showed an association with erlotinib-induced hepatotoxicity included concomitant use of cytochrome P450 3A4 (CYP3A4) inducers and H2-antagonist/proton pump inhibitors, liver metastasis, and age ≥ 65. Particularly in patients using CYP3A4 inducers and anti-acid secreting agents, liver function should be closely monitored.