Finasteride: study card

Finasteride — 5-alpha reductase inhibitor. Study the mechanism, listed uses and warnings from the US label on one sourced card.

Generic name: Finasteride
Class: 5-alpha reductase inhibitor
Mechanism: Competitive, specific inhibitor of type II 5-alpha reductase, blocking conversion of testosterone to DHT.
Used for: Symptomatic benign prostatic hyperplasia in men with an enlarged prostate, to improve symptoms; Reduction of acute urinary retention and BPH-related surgery risk in men with an enlarged prostate; Reduction of symptomatic BPH progression when combined with doxazosin
Common side effects: Impotence; Decreased libido; Decreased ejaculate volume; Breast enlargement / tenderness; Rash
Warnings: Lowers PSA by about 50% within six months; a confirmed rise from the on-treatment lowest value requires evaluation; May increase high-grade prostate cancer risk; Contraindicated in pregnancy (male fetus risk)

Brand questions use only name pairings verified against the linked product source. Unverified pairings are withheld from these questions; the other study content remains available.

Drug class families: 5-alpha reductase inhibitors

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Label date: 20260820 · For learning, not clinical decisions. US label and brand information; always consult the current source.

Source snapshot checked: 2026-10-21. The source document and selected fields were compared. The complete card has not had an independent clinical review.

Practice

Pronunciation

Finasteride: fi-NAS-teer-ide

Pronunciation is shown for the US English generic name.

Other drugs in the same class

5-alpha reductase inhibitors: Dutasteride

Body system

Genitourinary · 11 Drug cards

Compare with related cards

Dutasteride

Same class family: 5-alpha reductase inhibitors

Mechanism: Competitively inhibits type 1 and type 2 5-alpha reductase, blocking conversion of testosterone to DHT.

On both cards: Common side effects — Impotence; Decreased libido

Only on the Dutasteride card: Used for — Symptomatic benign prostatic hyperplasia in men with an enlarged prostate; The same symptomatic BPH/enlarged-prostate indication in combination with tamsulosin · Common side effects — Ejaculation disorders; Breast disorders · Warnings — Lowers serum PSA (reinterpret values); Possible higher risk of high-grade prostate cancer; Pregnant women should not handle capsules

An item counts as shared only when both cards use the same wording. If a card does not list an item, that is not a statement that the effect never occurs.