In Vivo Investigation in Pigs of Intestinal Absorption, Hepatobiliary Disposition, and Metabolism of the 5α-Reductase Inhibitor Finasteride and the Effects of Coadministered Ketoconazole

February 2011 in “ Drug Metabolism and Disposition ”

Anna Lundahl, Mikael Hedeland, Ulf Bondesson, Hans Lennernäs

finasteride 5α-reductase inhibitor ketoconazole male pattern baldness Propecia

TLDR Ketoconazole increases finasteride's effectiveness and lifespan in the body.

This study investigated the pharmacokinetics and metabolism of finasteride, a 5α-reductase inhibitor used to treat benign prostatic hyperplasia and male pattern baldness, in pigs. The study found that ketoconazole increased the bioavailability of finasteride and the terminal half-life. The liver extraction ratio was time-dependent and varied with the two routes of administration. After intrajejunal administration, the liver extraction ratio was significantly reduced by ketoconazole treatment. The study provides valuable insights into the pharmacokinetics of finasteride and its interactions with other drugs.

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Research cited in this study

6 / 6 results

research Saturable Binding of Finasteride to Steroid 5α-Reductase as Determinant of Nonlinear Pharmacokinetics

16 citations , January 2010 in “Drug Metabolism and Pharmacokinetics”

Finasteride's effect on hair loss and prostate enlargement depends on its binding to an enzyme, with maximum impact at 0.2 mg dose.

Identification of Finasteride Metabolites in Human Bile and Urine by High-Performance Liquid Chromatography/Tandem Mass Spectrometry

research Identification of Finasteride Metabolites in Human Bile and Urine by High-Performance Liquid Chromatography/Tandem Mass Spectrometry

18 citations , July 2009 in “Drug Metabolism and Disposition”

Finasteride breakdown products found in bile and urine, helps understand drug safety and effectiveness.

The Effect of St. John's Wort on the Pharmacokinetics, Metabolism, and Biliary Excretion of Finasteride and Its Metabolites in Healthy Men

research The Effect of St. John's Wort on the Pharmacokinetics, Metabolism, and Biliary Excretion of Finasteride and Its Metabolites in Healthy Men

33 citations , November 2008 in “European Journal of Pharmaceutical Sciences”

St. John's wort increases finasteride metabolism, reducing its effectiveness; use caution when combining them.

research Clinical Pharmacokinetics and Pharmacodynamics of Finasteride

93 citations , January 1996 in “Clinical Pharmacokinectics”

Finasteride helps regrow hair and shrink prostate by reducing DHT, with some sexual side effects.

research Finasteride, A Steroid 5α-Reductase Inhibitor, Does Not Affect the Oxidative Metabolism of Antipyrine

9 citations , October 1993 in “The Journal of Clinical Pharmacology”

Finasteride doesn't affect antipyrine metabolism, so interactions with cytochrome P-450 enzyme drugs are unlikely.

research Finasteride: The First 5 Alpha-Reductase Inhibitor

34 citations , July 1993 in “PubMed”

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research The Effect of St. John's Wort on the Pharmacokinetics, Metabolism, and Biliary Excretion of Finasteride and Its Metabolites in Healthy Men

33 citations , November 2008 in “European Journal of Pharmaceutical Sciences”

St. John's wort increases finasteride metabolism, reducing its effectiveness; use caution when combining them.