Phenytoin Toxicity During Neoadjuvant Concurrent Capecitabine and Radiation Therapy for Rectal Adenocarcinoma: Case Report of a Drug Interaction

Clare McGrath; Amy Munro; Rakesh Goel; Kelly Linden; Kristopher Dennis

doi:10.7759/cureus.3625

Phenytoin Toxicity During Neoadjuvant Concurrent Capecitabine and Radiation Therapy for Rectal Adenocarcinoma: Case Report of a Drug Interaction

Cureus. 2018 Nov 23;10(11):e3625. doi: 10.7759/cureus.3625.

Authors

Clare McGrath¹, Amy Munro², Rakesh Goel³, Kelly Linden¹, Kristopher Dennis⁴

Affiliations

¹ Radiation Oncology, The Ottawa Hospital Cancer Centre, Ottawa, CAN.
² Radiation Oncology, McMaster University, Hamilton, CAN.
³ Oncology, The Ottawa Hospital Cancer Centre, Ottawa, CAN.
⁴ Radiation Oncology, The University of Ottawa, Ottawa, CAN.

Abstract

Phenytoin toxicity occurs when serum levels exceed the therapeutic level, leading to symptoms such as nystagmus, slurred speech, and decreased coordination. This toxicity is sometimes caused by drug interactions. Interactions between phenytoin and capecitabine are not commonly documented. We report the case of a 52-year-old man taking phenytoin for atypical meningioma who developed symptoms of phenytoin toxicity while receiving capecitabine in the treatment of rectal adenocarcinoma.

Keywords: 5-fluorouracil; capecitabine; drug interaction; phenytoin; rectal cancer.

Publication types

Case Reports