Is finasteride (5-alpha-reductase inhibitor) plus Flomax (tamsulosin, alpha-blocker) recommended for treating moderate to severe benign prostatic hyperplasia (BPH) symptoms?

Combination Therapy with Finasteride and Tamsulosin (Flomax) for BPH

Yes, combination therapy with finasteride plus tamsulosin (Flomax) is recommended for men with moderate-to-severe BPH symptoms who have demonstrable prostatic enlargement (prostate volume >30 mL), as this regimen provides superior long-term outcomes in preventing disease progression, acute urinary retention, and the need for surgery compared to either medication alone. 1, 2, 3

Patient Selection Criteria

Combination therapy is most appropriate for patients meeting ALL of the following criteria:

• Moderate-to-severe lower urinary tract symptoms (AUA Symptom Score >8) 2
• Documented prostatic enlargement (prostate volume >30-35 mL) 2, 4
• Elevated PSA levels (≥1.5-2.0 ng/mL) for maximum benefit 2, 4

Patients with larger prostates (≥40 mL) and higher PSA values have the greatest absolute benefit due to higher baseline risk of disease progression. 1, 2

Evidence for Superiority of Combination Therapy

Long-Term Disease Modification

The landmark MTOPS trial demonstrated that combination therapy provides sustained benefits over 4-6 years:

• 67% reduction in overall clinical progression (compared to 39% for alpha-blocker alone and 34% for finasteride alone) 1, 4
• 79% reduction in acute urinary retention (compared to 31% for alpha-blocker alone and 67% for finasteride alone) 1
• 67% reduction in need for BPH-related surgery (compared to no significant change with alpha-blocker alone) 1

Symptom Relief

While short-term studies (≤1 year) showed no advantage of combination therapy over alpha-blocker monotherapy for symptom relief, the 5-year MTOPS study demonstrated that combination therapy is more effective in relieving and preventing progression of symptoms than alpha-blocker monotherapy over the long term. 1

Treatment Algorithm

Initial Assessment

• Confirm moderate-to-severe LUTS (AUA Symptom Score >8) 2
• Document prostatic enlargement via digital rectal exam or imaging (target >30 mL) 2
• Measure baseline PSA (ideally ≥1.5 ng/mL for optimal benefit) 2, 4

Dosing Regimen

• Tamsulosin 0.4 mg once daily (modified-release formulation, no titration required) 2
• Finasteride 5 mg once daily 3
• FDA-approved combination includes finasteride with doxazosin, though tamsulosin is commonly used 3

Duration of Therapy

Continue combination therapy indefinitely (long-term) in patients with enlarged prostates and elevated PSA, as benefits are sustained and cumulative over time. 4 The primary value of the 5-alpha-reductase inhibitor is disease modification and prevention of long-term complications, not just symptom relief. 4

Critical Pitfalls to Avoid

Do NOT Use Combination Therapy If:

• Patient lacks prostatic enlargement – finasteride is ineffective without documented prostate enlargement and exposes patients to unnecessary side effects 1, 2, 5
• Patient has mild symptoms – the cost and side effect burden may outweigh benefits in low-risk patients 1

Important Safety Considerations

PSA Monitoring: Finasteride reduces PSA by approximately 50% after 1 year of therapy. 2, 5 Double the measured PSA value after 1 year of finasteride therapy for accurate prostate cancer screening interpretation. 2, 5

Ophthalmologic Surgery: Tamsulosin is associated with intraoperative floppy iris syndrome during cataract surgery. 2 Patients must inform their ophthalmologist before any eye surgery.

Cardiovascular Considerations: Alpha-blocker therapy should not be assumed to constitute optimal management of concomitant hypertension; patients may require separate antihypertensive management. 2

Sexual Side Effects: Combination therapy adverse events reflect the combined profiles of both medications, including decreased libido (6.4% in first year with finasteride), ejaculatory dysfunction (3.7%), and erectile dysfunction, though these typically become less common after the first year. 5, 3

Timeline for Expected Benefits

• Tamsulosin: Symptom improvement within days to weeks 2
• Finasteride: Onset of action is slower; patients typically notice improvement after 3-6 months, with maximum prostate volume reduction (15-25%) achieved by 6 months 2, 5
• Allow at least 6 months to assess finasteride's effectiveness before considering treatment failure 5, 3

When Monotherapy May Be Appropriate

Alpha-blocker monotherapy may be considered for patients with moderate-to-severe symptoms but without prostatic enlargement or with smaller prostates (<30 mL), as finasteride provides no benefit in this population. 1, 2

Finasteride monotherapy is less effective than alpha-blockers for symptom relief and is generally not recommended as first-line therapy, though it does reduce long-term risk of acute urinary retention and surgery in men with enlarged prostates. 1, 3