A life-threatening drug-drug interaction between capecitabine and brivudine in a patient with metastatic breast cancer.

In the current report we present the case of a patient experiencing a life-threatening drug-drug interaction involving the concurrent administration of capecitabine and brivudine. A 65- year-old female with metastatic breast cancer was commenced on brivudine for Herpes Zoster, while on capecitabine treatment, by a physician unfamiliar with the potential repercussions of this drug-drug interaction. As a result, she developed skin rash, severe oral mucositis, and severe and prolonged pancytopenia.