Clinical pharmacokinetics of fluvastatin.

Area of Science:

• Pharmacology
• Cardiovascular Medicine

Background:

• Fluvastatin is a synthetic HMG-CoA reductase inhibitor used for hyperlipidemia and coronary heart disease.
• It is relatively hydrophilic, leading to extensive gastrointestinal absorption and hepatic metabolism.

Purpose of the Study:

• To detail the pharmacokinetic profile of fluvastatin.
• To investigate potential drug interactions with fluvastatin, particularly concerning cytochrome P450 enzymes.

Main Methods:

• Analysis of fluvastatin absorption, distribution, metabolism, and excretion.
• In vitro and in vivo studies to assess interactions with various drug classes, including CYP450 inhibitors and inducers, and gastrointestinal agents.

Main Results:

• Fluvastatin is extensively metabolized in the liver to hydroxylated and N-desisopropyl metabolites, primarily excreted in bile.
• CYP2C9 and CYP3A4 are involved in its metabolism; specific metabolites are exclusively formed by CYP2C9.
• Fluvastatin has minimal extrahepatic distribution and its pharmacokinetics are not affected by renal function.
• While CYP3A4 inhibitors do not affect fluvastatin, it inhibits CYP2C9, reducing the clearance of some substrates (diclofenac, tolbutamide) by 15-25%, though not clinically significant.
• Interactions with warfarin and phenytoin require caution due to narrow therapeutic indices.

Conclusions:

• Fluvastatin exhibits a favorable pharmacokinetic profile with limited interactions, primarily due to its hepatic metabolism and biliary excretion.
• Its inhibitory effect on CYP2C9 warrants caution when coadministered with narrow therapeutic index CYP2C9 substrates like warfarin and phenytoin.