Conjunctivitis associated with capecitabine treatment in a patient with colon cancer: The importance on educating patients into identifying adverse reactions.

INTRODUCTION: Conjunctivitis is an inflammation of the conjunctiva, a thin translucent mucous membrane, characterized by a dilatation of the conjunctival vessels. Causes leading to conjunctivitis are diverse, being drug related one of them. CASE REPORT: We report a case of an 80-year-old man with a diagnosis of relapsed stage IV colon cancer who developed a severe conjunctivitis, scar ectropion with lack of tissue and eversion of the subconjunctival conjunctiva after being treated with capecitabine. MANAGEMENT AND OUTCOME: Capecitabine was discontinued and pharmacological treatment was initiated with a complete resolution of the symptoms. DISCUSSION: Ocular toxicity derived from the use of systemic fluorouracil has been widely described in the literature, as well as the relationship between the use of capecitabine and the appearance of conjunctivitis. However, the development of severe conjunctivitis with other complications has not been previously reported. Monitor patients closely and perform full medication assessment should be undertaken when a patient reports visual changes to manage toxicity in the early stages. Following the patient evaluation and evolution and based on the Karch Lasanga algorithm modified by Naranjo, the adverse reaction is considered as probable.

Probable drug-drug interaction between erlotinib and amiodarone causes severe neurotoxicity in a patient with advanced lung cancer.

Drug-drug interactions (DDIs) are of great concern in the treatment of cancer, especially when target therapies, such as tyrosine kinase inhibitors, are being used. Here, we report a case of probable DDI between erlotinib and amiodarone leading to severe neurotoxicity. Amiodarone inhibits P-glycoprotein (P-gp), for which erlotinib is a substrate. P-gp is an important drug transporter that is involved in limiting the blood-brain barrier penetration of erlotinib. Clinicians should be aware of emerging data characterizing the effect of the P-gp transport system on drug exposure and its potential for DDI.