Finasteride: Uses, Dosage & Side Effects

Finasteride is a selective inhibitor of type II 5-alpha reductase, an enzyme that converts testosterone to its more potent metabolite, dihydrotestosterone (DHT). It reduces DHT levels in prostate and scalp tissue.

Benign Prostatic Hyperplasia (5 mg):

• Moderate-to-severe lower urinary tract symptoms
• Urinary retention
• Recurrent urinary tract infections
• Hematuria due to BPH

Male Pattern Hair Loss (1 mg):

• Androgenetic alopecia vertex and anterior midscalp
• Prevention of further hair loss progression
• Not effective for frontal alopecia in all patients

BPH:

• 5 mg once daily (Proscar)
• Take with or without food
• Maximum effect: 6-12 months of continuous therapy

Hair Loss:

• 1 mg once daily (Propecia)
• Take with or without food
• Discontinuation results in hair loss regression within 3-12 months

Common: Erectile dysfunction (2-7%), decreased libido, ejaculatory dysfunction, gynecomastia Rare: Depression, anxiety, persistent sexual dysfunction after discontinuation

• Pregnancy or women of childbearing potential
• Hypersensitivity to finasteride
• Pediatric use (not indicated)
• Children exposed to finasteride (through handling or exposure)

• Minimal significant interactions
• May interact with strong CYP3A4 inhibitors (theoretically)
• No interactions with common cardiovascular medications

PLESS trial (NEJM 1998) demonstrated 31% reduction in prostate volume and improvement in symptom scores over 4 years. PROPECIA trial showed 66% of men experienced stabilization or improvement in hair loss. Combination with alpha-blockers provides superior symptom improvement in BPH.

• Baseline assessment before initiating therapy
• Regular clinical follow-up per indication
• Laboratory parameters as specified in sections above
• Drug interaction screening at each visit

Dosing adjustments may be necessary in:

• Renal impairment
• Hepatic impairment
• Elderly patients
• Pregnancy and lactation
• Pediatric patients

• Take exactly as directed; do not modify dose without consulting healthcare provider
• Report any unusual symptoms or adverse effects
• Maintain regular follow-up appointments
• Store at room temperature away from moisture and light
• Keep out of reach of children

Disclaimer: This information is for educational purposes only and should not substitute for professional medical advice. Always consult with a qualified healthcare provider before starting, stopping, or modifying any medication.