Does finasteride help with Benign Prostatic Hyperplasia (BPH)?

Finasteride's Effectiveness in Benign Prostatic Hyperplasia (BPH)

Finasteride is an effective treatment for BPH in men with enlarged prostates, reducing prostate size, improving urinary symptoms, and significantly lowering the risk of acute urinary retention and BPH-related surgery. 1

Mechanism and Efficacy

Finasteride works by inhibiting 5-alpha-reductase, which:

• Reduces prostatic dihydrotestosterone (DHT) levels
• Decreases prostate size by 20-25% after 6 months of therapy 2
• Increases peak urinary flow rate
• Improves BPH symptoms

The average patient experiences approximately a 3-point improvement on the AUA Symptom Index, which is generally perceived as a meaningful clinical change 1.

Patient Selection: Who Benefits Most

Finasteride is most appropriate for:

• Men with demonstrable prostatic enlargement (≥40 ml)
• Patients with moderate to severe LUTS associated with BPH

Important: Finasteride is NOT appropriate for men with LUTS who do not have evidence of prostatic enlargement 1. This is a critical distinction as treatment efficacy depends on the presence of an enlarged prostate.

Clinical Benefits

Long-term benefits (based on 4-year studies) include:

• 55% reduction in risk of BPH-related surgery 3
• 57% reduction in risk of acute urinary retention 3
• Sustained improvement in urinary symptoms
• Prevention of disease progression

Comparison with Other Treatments

• Alpha blockers: Finasteride is less effective than alpha blockers (like doxazosin or terazosin) for immediate symptom relief 1, 4
• Combination therapy: The combination of finasteride with an alpha-blocker (particularly doxazosin) is more effective than finasteride alone for long-term symptom management and prevention of disease progression 1, 5

Adverse Effects

The most common side effects are sexually related and include:

• Decreased libido
• Ejaculatory dysfunction
• Erectile dysfunction

These effects are generally:

• Reversible
• Uncommon after the first year of therapy
• Occur in only about 2-3% of patients 6

Treatment Algorithm

1. Assess prostate size (via digital rectal exam, ultrasound, or PSA as surrogate)
2. If prostate is enlarged:
   • For moderate symptoms: Consider finasteride monotherapy
   • For more severe symptoms: Consider combination therapy with alpha blocker
3. If prostate is not enlarged: Do not use finasteride; consider alpha blocker instead
4. Monitor response: Evaluate after 6-12 months of therapy (improvement may take time)
5. Long-term management: Continue therapy indefinitely as benefits are maintained only with ongoing treatment

Important Considerations

• Finasteride lowers serum PSA levels but does not mask PSA-based detection of prostate cancer 1
• Treatment must be continued long-term as withdrawal results in regrowth of the prostate 6
• Clinical improvement may not become apparent until after at least 6 months of therapy 6
• Finasteride is not approved for the prevention of prostate cancer 5

Conclusion

Finasteride is a valuable treatment option for men with BPH who have enlarged prostates. While its symptom improvement may be modest compared to surgical options, its ability to reduce disease progression and prevent complications like acute urinary retention makes it an important medication in the management of BPH.