Rapid onset of conjunctivitis associated with overdosing of erlotinib

What is known and objectiveErlotinib is one of the epidermal growth factor receptor (EGFR) inhibitors and is widely used as a targeted therapy for advanced non-small-cell lung cancer (NSCLC). There are a few reports regarding ocular adverse effects of erlotinib. Herein, we report a case of rapid onset of ocular toxicity associated with overdosing of erlotinib. Case descriptionA 72-year-old male with metastatic NSCLC developed conjunctivitis after accidentally taking erlotinib at a dosage of 300mg/day for 4days. Before that, the patient had been taking erlotinib at the prescribed dose of 150mg/day for 17days. Erlotinib was discontinued for 7days, and the conjunctivitis was successfully treated symptomatically. The adverse effect did not recur when he resumed taking erlotinib 150mg/day, suggesting the ocular change was related to the overdosing of erlotinib. What is new and conclusionAwareness and close monitoring of this adverse effect are helpful for doctors and pharmacists to identify inadvertent drug overdose. Patients should be provided comprehensive education before receiving targeted therapy.