finasteride

A competitive inhibitor of steroid 5α-reductase, an intracellular enzyme that converts testosterone into 5α-dihydrotestosterone, a potent androgen; used in the treatment of benign prostatic hyperplasia; also used to treat male pattern baldness and to regrow hair.

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fi·nas·te·ride fə-'nas-tə-.rīd n a nitrogenous steroid derivative C₂₃H₃₆N₂O₂ that is used esp. to treat symptoms of benign prostatic hyperplasia and to increase hair growth in male-pattern baldness and that acts by inhibiting the enzymatic conversion of testosterone to dihydrotestosterone see propecia, PROSCAR

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n.

a drug that causes shrinkage of the prostate gland. It is administered by mouth both to relieve the symptoms of urinary retention caused by an enlarged gland obstructing the outflow of urine from the bladder and to reduce the risk of urinary retention. The drug acts by reducing androgenic stimulation of the prostate, inhibiting the enzyme responsible for converting testosterone to its more active metabolite, 5-dehydroxytestosterone (5-DHT), within the gland. It is sometimes also prescribed in men who have recurrent bleeding from the prostate. Trade name: Proscar.

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fi·nas·te·ride (fĭ-nasґtər-īd) [USP] an inhibitor of 5α-reductase, used in the treatment of benign prostatic hyperplasia and as a hair growth stimulant in the treatment of androgenetic alopecia; administered orally.