Classifications: hormone; antiandrogen; 5-alpha reductase inhibitor; Therapeutic: antiandrogen
Pregnancy Category: X
1 mg, 5 mg tablets
Specific inhibitor of the steroid 5-alpha-reductase, an enzyme necessary to convert testosterone into the potent androgen
5-alpha-dihydrotestosterone (DHT) in the prostate gland.
Decreases the production of testosterone in the prostate gland.
Benign prostatic hypertrophy, male pattern hair loss (androgenetic alopecia).
Hypersensitivity to finasteride; pregnancy (category X), lactation, females, and children.
Hepatic impairment, obstructive uropathy.
Route & Dosage
|Benign Prostatic Hypertrophy
Adult: PO 5 mg/d
Male Pattern Hair Loss
Adult: PO 1 mg q.d.
- Crush tablets if necessary. Pregnant women should not handle the crushed drug; if absorbed through the skin it may be harmful
to a male fetus.
- Store at 15°30° C (59°86° F) unless otherwise directed.
Adverse Effects (≥1%)Urogenital:
Impotence, decreased libido, decreased volume of ejaculate.
Diagnostic Test Interference
Depresses levels of DHT and prostate-specific antigen (PSA). Testosterone levels usually are increased.
No clinically significant interactions established. Herbal: Saw palmetto
may potentiate effects of finasteride.
Readily from GI tract. Onset:
36 mo. Duration:
57 d. Elimination:
39% in urine, 57% in feces. Half-Life:
Assessment & Drug Effects
- Evaluate carefully any sustained increase in serum PSA levels while patient is taking finasteride. It may indicate the presence
of prostate cancer or noncompliance with the therapy.
- Monitor patients with a large residual urinary volume or decreased urinary flow. These patients may not be candidates for
Patient & Family Education
- Use a barrier contraceptive to prevent pregnancy in a sexual partner.
- Be aware that impotence and decreased libido may occur with treatment.