Effect of L-cysteine on distribution volume of 1-(tetrahydro-2-furanyl)-5-fluorouracil.

Higher plasma concentrations of 1-(tetrahydro-2-furanyl)-5-fluorouracil (FT) were obtained after administration of FT (100 mg/kg, i.v.) combined with L-cysteine (CySH, 500 mg/kg, p.o.). The volume of distribution (Vd) and body fluid volumes significantly decreased. These results suggest that the increase of the plasma concentrations of FT can be attributed to the decrease of the Vd of FT, which is considered to be based on the decrease of body fluid volumes by the combined administration of CySH.