Rechallenge of 5-Fluorouracil in a Patient With Coronary Vasospasm Unable to Receive Oral Medications

Fluoropyrimidines, such as 5-fluorouracil (5-FU) and capecitabine, are vital in gastrointestinal cancer treatment but can cause coronary vasospasm (CV). Although calcium channel blockers and nitrates enable rechallenge, the optimal management of patients who cannot tolerate oral medications remains uncertain. A 38-year-old man with metastatic gastric adenocarcinoma developed 5-FU-induced CV during 5-FU, leucovorin, oxaliplatin, and docetaxel chemotherapy. Rechallenge with extended-release nifedipine and isosorbide mononitrate was initially successful, but worsening dysphagia precluded oral prophylaxis. Transdermal nitroglycerin was attempted but failed, necessitating 5-FU interruption and sublingual nitroglycerin. Because of inadequate oncologic response and human epidermal growth factor receptor 2 positivity, treatment transitioned to trastuzumab. This case highlights the challenge of 5-FU rechallenge in patients unable to take oral prophylaxis. Transdermal nitroglycerin monotherapy proved insufficient, suggesting that intravenous prophylaxis may be required. Future studies should determine optimal strategies for preventing CV in patients with a similar presentation.