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Altered tolbutamide pharmacokinetics by a decrease in hepatic expression of CYP2C6/11 in rats pretreated with
Shuhei Fukuno1, Katsuhito Nagai1,2, Keita Kasahara1
1a Laboratory of Clinical Pharmacy and Therapeutics , Faculty of Pharmacy, Osaka Ohtani University , Tondabayashi , Japan and.
Single 5-fluorouracil (5-FU) administration altered tolbutamide (TB) pharmacokinetics in rats. This change was linked to reduced CYP2C6/11 gene expression and metabolic activity, impacting drug clearance.
Area of Science:
- Pharmacology
- Drug Metabolism
- Toxicology
Background:
- Tolbutamide (TB) is metabolized by cytochrome P450 enzymes, specifically CYP2C6 and CYP2C11.
- 5-fluorouracil (5-FU) is a widely used chemotherapeutic agent with known drug interaction potential.
Purpose of the Study:
- To investigate the impact of 5-fluorouracil (5-FU) on the pharmacokinetic profile of tolbutamide (TB).
- To examine the effects of 5-FU on hepatic CYP2C6/11 gene expression and enzyme activity.
Main Methods:
- Rats were pretreated with a single dose of 5-FU.
- Pharmacokinetic parameters of TB were analyzed in 5-FU-treated and control rats.
- Hepatic microsomal metabolism of TB and mRNA expression levels of CYP2C6/11 were assessed.
Main Results:
- 5-FU administration significantly increased the area under the curve (AUC) and decreased the elimination rate constant (ke) of TB.
- Metabolic production of 4-hydroxylated TB was significantly reduced in hepatic microsomes from 5-FU-treated rats.
- mRNA expression levels of hepatic CYP2C6 and CYP2C11 were significantly lower in 5-FU-pretreated rats compared to controls.
Conclusions:
- 5-FU treatment alters the pharmacokinetic profile of TB in rats.
- The observed changes are attributed to a metabolic process involving decreased CYP2C6/11 expression at the mRNA level.
- This study highlights a potential drug interaction between 5-FU and TB, mediated by CYP450 enzyme inhibition.
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