TLDR St. John's wort increases finasteride metabolism, reducing its effectiveness; use caution when combining them.
This study investigated the effect of St. John's wort on the pharmacokinetics, metabolism, and biliary excretion of finasteride and its metabolites in healthy men. The results showed that SJW treatment significantly reduced the peak plasma concentration, the area under the plasma concentration-time curve, and the elimination half-life of finasteride. The biliary and urinary excretion of the drug and its metabolites were also affected. The study concluded that SJW treatment induced the metabolism of finasteride and caused a reduced plasma exposure of the drug. Therefore, caution should be exercised when using St. John's wort in combination with finasteride.
1054 citations,
February 1998 in “The New England Journal of Medicine” Finasteride reduces urinary issues and surgery need in men with enlarged prostates by over 50%.
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January 1996 in “Clinical Pharmacokinectics” Finasteride helps regrow hair and shrink prostate by reducing DHT, with some sexual side effects.
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October 1993 in “The Journal of Clinical Pharmacology” Finasteride doesn't affect antipyrine metabolism, so interactions with cytochrome P-450 enzyme drugs are unlikely.
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July 1993 in “Pharmacotherapy” Finasteride treats enlarged prostate and baldness, but may cause limited urinary improvement and sex-related side effects.
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June 1993 in “Biochemistry” Finasteride slowly binds to 5-alpha-reductase, affecting enzyme stability and inhibitor potency.
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October 1992 in “The New England Journal of Medicine” Finasteride effectively treats BPH but may increase sexual dysfunction risk.
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April 1990 in “The Journal of Clinical Endocrinology and Metabolism” Finasteride safely lowers DHT levels without affecting testosterone.
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.
