Hepatic fibrosis does not affect the pharmacokinetics of 5-fluorouracil in rats.

In the case of cancer chemotherapy for hepatocellular carcinoma, 5-fluorouracil (5-FU) is used widely, and has typically been given by intrahepatic arterial (i.a.) infusion to increase treatment efficacy and to reduce systemic toxicity. 5-Fluorouracil is eliminated primarily by the liver, and so its use in patients with hepatic disease can be difficult. This study investigated the effect of hepatic fibrosis on the pharmacokinetics of 5-FU in rats. Experimental hepatic fibrosis was induced by carbon tetrachloride treatment. 5-fluorouracil was infused for 15 min into the hepatic artery or the saphenous vein of the rats at a dose of 1.25 mg/kg. There were no significant differences in the plasma concentration and AUC of 5-FU between hepatic disease rats and their controls after both intravenous and intraarterial injection. This result is probably attributed to the fact that there were no significant differences in hepatic blood flow and dihydropyrimidine dehydrogenase (DPD; an initial and rate-limiting enzyme in 5-FU catabolism) activity between hepatic disease rats and their controls, because the total clearance of 5-FU after intravenous and intraarterial administration is mainly limited by hepatic blood flow and DPD activity, respectively. In conclusion, the pharmacokinetics of 5-FU is not affected by hepatic fibrosis, unlike that of many hepatically metabolized drugs.

Effect of acute hepatic failure on the hepatic first-pass effect of 5-fluorouracil in rats.

OBJECTIVES: In cancer chemotherapy for hepatocellular carcinoma, 5-fluorouracil is widely used and has typically been given by intrahepatic arterial (i.a.) infusion to increase treatment efficacy and reduce systemic toxicity. 5-Fluorouracil is eliminated primarily by the liver and so the hepatic first-pass effect after intrahepatic arterial administration of 5-fluorouracil may be lower in patients with hepatic failure, and systemic toxicity may not be reduced. In this study, we have investigated the effect of acute hepatic failure on the first-pass effect of 5-fluorouracil in rats. METHODS: Experimental acute hepatic failure was induced by treatment with carbon tetrachloride (CCl4). 5-Fluorouracil was infused for 15 min into the hepatic artery or the saphenous vein of rats at a dose of 1.25 mg/kg. KEY FINDINGS: Hepatic availability in 50% CCl4-treated (severe hepatic failure) rats was higher than in controls. CONCLUSIONS: The hepatic first-pass effect after intrahepatic arterial administration of 5-fluorouracil was lower in severe hepatic failure. Therefore, the reducing effect of the systemic toxicity after intrahepatic arterial administration may be lower in severe hepatic failure.