Finasteride and Tamsulosin Combination Therapy for BPH
Yes, finasteride can be safely and effectively taken with tamsulosin, and this combination therapy is actually recommended for long-term management of benign prostatic hyperplasia (BPH) with prostatic enlargement as it provides superior outcomes compared to either medication alone. 1
Mechanism and Rationale for Combination Therapy
The combination works through complementary mechanisms:
- Tamsulosin (α1-blocker): Relaxes smooth muscle in the prostate and bladder neck, providing rapid symptom relief
- Finasteride (5α-reductase inhibitor): Reduces prostate size over time by blocking conversion of testosterone to dihydrotestosterone
Evidence Supporting Combination Therapy
Long-term data from major clinical trials demonstrate that combination therapy is superior to either monotherapy:
The CombAT study showed combination therapy reduced:
- Risk of acute urinary retention by 68%
- BPH-related surgery by 71%
- Symptom deterioration by 41% compared to tamsulosin alone 1
To prevent one case of urinary retention or surgical treatment, 13 patients need treatment for 4 years with the combination therapy 1
Appropriate Patient Selection
Combination therapy is most appropriate for:
- Patients with moderate-to-severe lower urinary tract symptoms (LUTS)
- Evidence of prostatic enlargement
- Intention for long-term treatment 1
Finasteride is not appropriate for men with LUTS who do not have evidence of prostatic enlargement 1.
Efficacy Timeline
- Tamsulosin: Provides rapid symptom relief within weeks
- Finasteride: Takes 3-6 months to achieve maximum effect through prostate size reduction
- Combination: Provides both immediate relief and long-term disease modification 1, 2
Side Effects and Considerations
The combination therapy has side effects typical of both medications:
- Tamsulosin-related: Orthostatic hypotension, dizziness, ejaculatory dysfunction (more common than with other α-blockers) 1, 3
- Finasteride-related: Sexual dysfunction (erectile dysfunction, decreased libido, ejaculation disorders) 1, 4
- Combined therapy: Higher overall rate of adverse events than either monotherapy alone 1
Drug Interactions
No clinically significant metabolic interactions have been reported between tamsulosin and finasteride:
- Tamsulosin is extensively metabolized by CYP3A4 and CYP2D6 5
- In vitro studies show no evidence of clinically significant metabolic interactions between tamsulosin and finasteride 5
Special Considerations
- PSA monitoring: Finasteride reduces PSA levels by approximately 50% after 6-12 months; PSA values should be doubled for comparison with normal ranges in men taking finasteride 1
- Cataract surgery: Patients taking tamsulosin should inform their ophthalmologist before cataract surgery due to risk of intraoperative floppy iris syndrome 3
Conclusion
Combination therapy with finasteride and tamsulosin is well-established, effective, and safe for long-term management of BPH with prostatic enlargement. The combination provides both immediate symptom relief and long-term disease modification, reducing the risk of BPH progression more effectively than either medication alone.