Finasteride

PROSCAR, PROPECIA

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What it isType-2 5-alpha-reductase inhibitor; benign prostatic hyperplasia and androgenetic alopecia.

Why this oneUnlike dutasteride, it is labeled for male-pattern hair loss as well as BPH, giving one molecule two common long-term roles.

What limits itBenefit takes months. It lowers PSA and obscures trends; sexual dysfunction may persist, and pregnancy exposure threatens a male fetus.

FDA-approved for

BPH (1992)
hair loss (1997)

Off-label

female hirsutism

FDA label

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FDA dosing	Population	Start	Target	Max
Benign prostatic hyperplasia (monotherapy)	adult male	5 mg QD		5 mg QD
BPH — combination with doxazosin	adult male	5 mg QD		5 mg QD

Renal Undefined

Hepatic Undefined

Instructions

May be taken with or without meals.
Females who are or may be pregnant must not handle crushed or broken tablets (risk to a male fetus).

Contraindications

Pregnancy — females who are or may potentially be pregnant (risk of male fetal genital abnormalities)

Cautions

Reduces serum PSA ~50% — establish new baseline; evaluate any confirmed PSA increase
May increase risk of high-grade prostate cancer
Females should not handle crushed/broken tablets (male fetus risk)
Not indicated in children or females
Rule out other urologic conditions before treating BPH

Adverse reactions

Impotence
Decreased libido
Decreased ejaculate volume
Breast enlargement
Breast tenderness
Rash

Pregnancy Contraindicated; may cause abnormal development of male fetal external genitalia.

Lactation Not indicated for use in females.

NO BOXED WARNINGS

Principal riskSexual dysfunction, sometimes persistent

Cost, est. cash$4–$300/month

Generic entry2006

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk4 / 4

Legacy pregnancy categoryX

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.