Finasteride

Finasteride (fih-NAS-teh-ride) is a drug used to reduce the amount of male hormone (testosterone) produced by the body.

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Finasteride

Information about Finasteride

Finasteride is a 5-alpha reductase inhibitor used to treat symptoms of benign prostatic hypertrophy and male pattern baldness.

Liver safety of Finasteride

Finasteride is associated with a low rate of transient serum aminotransferase elevations, but has yet to be linked to instances of clinically apparent, acute liver injury.

Mechanism of action of Finasteride

Finasteride (fin as' ter ide) was the first 5-alpha reductase inhibitor to be approved for use as therapy of symptomatic benign prostatic hypertrophy in the United States. Finasteride inhibits the steroid 5-alpha reductase, which blocks the conversion of testosterone to dihydrotestosterone, a form of the androgenic hormone that is important in the development and maintenance of prostatic hyperplasia. Serum dihydrotesterone levels are decreased by 70% to 90% by finasteride therapy with little effect on testosterone levels. Finasteride takes several months to have an effect on prostate size and symptoms of prostatic hypertrophy (urinary hesitancy and poor stream), unlike the alpha-1 adrenergic receptor blockers which have a more immediate effect. Finasteride also inhibits the steroid 5-alpha reductase present in skin, which led to its use in the therapy or prevention of male pattern baldness.

FDA approval information for Finasteride

Finasteride was approved for use in the United States in 1992 and is available in 5 mg tablets generically and under the trade name Proscar for prostatic hypertrophy, and as 1 mg tablets under the name Propecia for male pattern baldness.

Dosage and administration for Finasteride

The recommended dose for therapy of prostatic hypertrophy is 5 mg once daily, and it generally requires 3 to 6 months before an effect is obtained and thereafter requires long term therapy. The dose of finasteride for male pattern baldness is 1 mg daily. It is not recommended as therapy for baldness in women.

Side effects of Finasteride

Side effects are uncommon, but include a low rate of impotence and decreased libido, gynecomastia, dizziness and weakness. Finasteride also decreases serum PSA levels (~50%), which should be monitored during therapy. Alpha-blockers used to treat benign prostatic hypertrophy (BPH):

• Alfuzosin
• Doxazosin
• Silodosin
• Tamsulosin
• Terazosin

5-Alpha Reductase Inhibitors

• Dutasteride
• Finasteride

• Dailymed label info on Finasteride
• FDA Finasteride

Finasteride Resources
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