Can I add Flomax (tamsulosin) to Finasteride (5mg)?

Combining Tamsulosin (Flomax) with Finasteride 5mg for BPH Treatment

Yes, you can add Flomax (tamsulosin) to finasteride 5mg as combination therapy is effective for treating lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH), especially in men with larger prostates and higher risk of disease progression.

Rationale for Combination Therapy

• Tamsulosin and finasteride work through different mechanisms - tamsulosin is an alpha-blocker that relaxes smooth muscle in the prostate and bladder neck, while finasteride is a 5-alpha-reductase inhibitor that reduces prostate size by inhibiting conversion of testosterone to dihydrotestosterone 1
• Combination therapy has been shown to be more effective in relieving and preventing progression of symptoms than alpha-blocker monotherapy in long-term studies 1
• The combination significantly reduces the long-term risk of acute urinary retention and the need for BPH-related surgery 1

Benefits of Combination Therapy

• Overall risk of BPH progression is reduced by 67% with combination therapy compared to 39% for alpha-blockers alone and 34% for finasteride alone 1
• Risk of acute urinary retention is reduced by 79% with combination therapy compared to 31% for alpha-blockers alone and 67% for finasteride alone 1
• Risk of surgery is reduced by 67% with combination therapy, similar to finasteride alone (64%), while alpha-blockers alone show no significant reduction 1

Specific Evidence for Tamsulosin + Finasteride

• While the best-tested combination in clinical trials has been doxazosin and finasteride, the American Urological Association guidelines indicate that the combination of any effective alpha-blocker (including tamsulosin) and 5-alpha-reductase inhibitor likely produces comparable benefits 1
• Multiple clinical studies have evaluated the tamsulosin/finasteride combination specifically, showing improvements in LUTS, maximum urinary flow rate, and reductions in prostate volume 2, 3
• The FDA label for finasteride specifically mentions that it can be used in combination with alpha-blockers 4

Who Benefits Most from Combination Therapy

• Patients most likely to benefit have a higher baseline risk of progression 1:
  • Larger prostate glands (>30cc) 1
  • Higher PSA values (>1.5ng/mL) 1
  • More severe symptoms 1

Dosing Considerations

• Finasteride: 5mg once daily (can be taken with or without meals) 4
• Tamsulosin: 0.4mg once daily, typically taken 30 minutes after the same meal each day 5
• Both medications can be started simultaneously 1, 4

Potential Side Effects

• Combination therapy combines the side effect profiles of both medications 1:
  • Alpha-blockers (tamsulosin): orthostatic hypotension, dizziness, headache, retrograde ejaculation 5
  • 5-alpha-reductase inhibitors (finasteride): decreased libido, erectile dysfunction, ejaculatory disorders, gynecomastia 1, 2
• Bothersome side effects tend to be more common in patients taking finasteride alone or as combination therapy compared to tamsulosin alone 2

Important Considerations

• Finasteride reduces PSA levels by approximately 50% after 6-12 months of treatment; if monitoring PSA for prostate cancer screening, the measured value should be doubled for accurate interpretation 1
• Tamsulosin may cause intraoperative floppy iris syndrome during cataract surgery, so inform your ophthalmologist if you take this medication 1
• Finasteride takes longer to show symptomatic improvement (3-6 months) compared to tamsulosin, which works more quickly (days to weeks) 1, 2

Combination therapy is a well-established approach for BPH management, particularly for patients with larger prostates who are at higher risk for disease progression. The tamsulosin/finasteride combination is widely used and supported by clinical evidence 3.