Can a patient on testosterone (Testosterone) therapy continue treatment with a Dihydrotestosterone (DHT) blocker, such as finasteride (Finasteride), if they develop Benign Prostatic Hyperplasia (BPH) with Lower Urinary Tract Symptoms (LUTS)?

Management of BPH with LUTS in Patients on Testosterone Therapy

Yes, patients on testosterone therapy who develop BPH with LUTS can continue treatment with a DHT blocker (5-alpha reductase inhibitor) such as finasteride. 1, 2

Pathophysiology and Rationale

• BPH is a testosterone-dependent condition where 5α-reductase converts testosterone to dihydrotestosterone (DHT), which has a higher affinity for androgen receptors and is the more potent androgenic steroid hormone responsible for prostate growth 1
• DHT forms a complex with androgen receptors that initiates transcription and translation, leading to prostate growth and hyperplasia 1
• 5-alpha reductase inhibitors (5-ARIs) like finasteride block the conversion of testosterone to DHT, reducing prostate size without affecting testosterone's other beneficial effects 1, 3

Treatment Algorithm for BPH/LUTS in Patients on Testosterone

First-line approach:

• Alpha blockers (alfuzosin, doxazosin, silodosin, tamsulosin, or terazosin) are the initial therapy of choice for most patients with moderate to severe LUTS/BPH 1
• For patients with prostate volume >30cc (as determined by imaging, PSA >1.5ng/mL, or palpable enlargement), consider adding a 5-ARI like finasteride 1

For patients already on testosterone therapy:

• If prostate is enlarged (>30cc) and the patient develops LUTS, adding finasteride is appropriate and effective 1, 2
• Finasteride can reduce prostate volume by approximately 20% and improve symptoms while allowing continuation of testosterone therapy 3, 4

Evidence Supporting 5-ARI Use

• Finasteride reduces the risk of acute urinary retention by 57% and the need for BPH-related surgery by 55% compared to placebo 2
• In the Medical Therapy of Prostatic Symptoms (MTOPS) study, finasteride reduced the risk of BPH progression by 34% compared to placebo 2
• Finasteride is FDA-approved for:
  • Improving symptoms of BPH
  • Reducing the risk of acute urinary retention
  • Reducing the risk of BPH-related surgery 2

Important Considerations and Monitoring

• Patients should be evaluated 4-12 weeks after initiating treatment to assess response and side effects 1
• For 5-ARIs like finasteride, waiting 3-6 months is advised to see full effects due to their slower onset of action 1
• Follow-up should include:
  • International Prostate Symptom Score (IPSS)
  • Quality of life assessment
  • Evaluation of medication side effects
  • When available, uroflowmetry and post-void residual (PVR) measurement 1

Potential Side Effects of 5-ARIs

• Sexual side effects are the most common adverse events with finasteride:
  • Decreased libido
  • Erectile dysfunction
  • Ejaculatory dysfunction 1, 5
• These side effects are typically reversible and often decrease after the first year of therapy 1
• 5-ARIs reduce PSA by approximately 50%, which should be considered when monitoring for prostate cancer 1, 4

Combination Therapy Considerations

• For patients with inadequate response to monotherapy, combination of an alpha blocker with a 5-ARI may provide superior symptom control 1, 6
• The combination of finasteride with an alpha blocker reduces the risk of BPH progression by 67% compared to placebo, which is better than either medication alone 2
• Combination therapy is particularly beneficial in patients with larger prostates (>30cc) 1, 6

Conclusion

For patients on testosterone therapy who develop BPH with LUTS, adding a 5-ARI like finasteride is an appropriate and effective treatment option, especially if there is evidence of prostate enlargement. This approach allows continuation of testosterone therapy while managing the BPH symptoms and reducing the risk of disease progression.