A Case Report of Delayed-Onset Cardiotoxicity Following Long-Term Use of 5-Fluorouracil: Underlining the Importance of Long-Term Pharmacovigilance

Abstract

Pharmacovigilance is vital for the identification, evaluation, and mitigation of adverse drug reactions, especially those with delayed onset. 5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent that has been a cornerstone in the management of various tumors. While generally well-tolerated, 5-FU is associated with a relatively rare side effect, cardiotoxicity, being clinically significant due to its potential for severe morbidity and mortality. A 40-year-old female patient with adenocarcinoma rectum treated with FOLFOX regimen presented in an unconscious state with lower GI bleed, low BP, and poor GCS to the emergency. Symptomatic treatment and multiple blood transfusions were given. Investigations revealed cardiomegaly, left-ventricular hypertrophy, mild mitral regurgitation, and a reduced ejection fraction (35%). Causality assessment was done, and patient was identified as a case of delayed-onset cardiotoxicity following long term use of 5-Fluorouracil. Patient was accordingly managed. The causality assessment of this case was possible as per the WHO-UMC causality assessment scale.