Question - What orally bioavailable prodrug is converted by 3 sequential enzymatic steps to produce 5-fluorouracil (5-FU) and whose consequent toxicity is identical to that of 5-FU? What is the antidote for overdose of either of these drugs?
Answer - The cited reference notes that “Capecitabine is an orally bioavailable prodrug converted by 3 sequential enzymatic steps to produce 5-fluorouracil”. These authors further notes that ”Uridine triacetate (Vistogard) was approved in 2015 for adult and pediatric patients who exhibit early-onset severe or life-threatening 5-FU/capecitabine toxicities or present with an overdose.” (Ma WW et al. Emergency Use of Uridine Triacetate for the Prevention and Treatment of Life-Threatening 5-Fluorouracil and Capecitabine Toxicity. 2017 Cancer 123(2): 345-356)