5-Fluorouracil
5-Fluorouracil. Pyrimidine antimetabolite — converted intracellularly to FdUMP (irreversible thymidylate-synthase inhibitor) and FUTP (RNA… IV half-life 0.2 h.
Pyrimidine antimetabolite — converted intracellularly to FdUMP (irreversible thymidylate-synthase inhibitor) and FUTP (RNA misincorporation). Backbone of colorectal, breast, GI cancer regimens. DPYD deficiency causes life-threatening toxicity (mandatory testing in some EU countries).
PK: THE HALF-LIFE IS A RANGE INTERIOR AND THE VOLUME IS UNSOURCED, BUT THE PAIR SURVIVES ITS ARITHMETIC. Its citation is a review that states "an apparent terminal half-life of approximately 8 to 20 minutes" and NO volume and NO clearance, so the stored 13.8 minutes is an interior pick close to the midpoint and the volume is class 1. The clearance the pair implies is high, which is the right qualitative shape for a drug the same abstract says is eliminated by "swift catabolism of the liver", and I found no verbatim absolute clearance to test it against — so the check is DECLARED AS NOT RUN rather than reported as passed. ONE CAVEAT IS FLAGGED AND DELIBERATELY NOT ASSERTED: this drug is widely described as having saturable, dose-dependent elimination, which would make a single first-order half-life structurally wrong, and its own cited review does not say so — so the concern is recorded and no rate constant is invented on the strength of it.
Pharmacokinetics
- IV — t½ 14 min · F 100% · Vd 25 L
Sources: PMID:2656050