Dutasteride and tamsulosin are both used to treat bph/">benign prostatic hyperplasia (BPH) but work through completely different mechanisms. Dutasteride shrinks the prostate by blocking DHT, providing long-term disease modification over months. Tamsulosin relaxes smooth muscle in the prostate and bladder neck, providing rapid symptom relief within days. In the 4-year CombAT trial the combination was superior to both monotherapies for symptom relief and for reducing BPH clinical progression, but it was not superior to dutasteride alone for reducing acute urinary retention or BPH-related surgery.
Comparison Table
| Feature | Dutasteride (Avodart) | Tamsulosin (Flomax) |
|---|---|---|
| Drug class | 5-alpha reductase inhibitor | Alpha-1 adrenergic blocker |
| Mechanism | Blocks DHT, shrinks prostate | Relaxes smooth muscle |
| Onset of effect | 3-6 months | Days to 2 weeks |
| Prostate shrinkage | Yes (20-25%) | No |
| Reduces surgery risk | Yes (48% risk reduction vs placebo at 2 years, FDA label) | No significant effect |
| Common side effects | Sexual dysfunction, gynecomastia | Dizziness, retrograde ejaculation |
| Hair loss benefit | Yes, but off-label (not FDA-approved for hair loss) | No |
The CombAT Trial
The landmark CombAT trial (4,844 men, 4 years) compared dutasteride alone, tamsulosin alone, and combination therapy. The combination (sold in the United States as Jalyn, and as Duodart or Combodart in other markets) was significantly superior to both monotherapies at reducing the relative risk of BPH clinical progression, and gave greater symptom benefit than either monotherapy at 4 years. For acute urinary retention and BPH-related surgery it was superior to tamsulosin alone but not to dutasteride alone. CombAT had no placebo arm. Read more about the Duodart combination.
Dutasteride for BPH · Dutasteride vs finasteride
Dutasteride alone shrinks the prostate over months, or it can be combined with tamsulosin (Jalyn in the US, Duodart or Combodart elsewhere) for rapid symptom relief plus long-term disease modification. Talk to a urologist or telehealth provider today.
Dutasteride and tamsulosin are prescription medications. A licensed provider must evaluate you before prescribing.
Sources
- Roehrborn CG, et al. The effects of combination therapy with dutasteride and tamsulosin on clinical outcomes in men with symptomatic benign prostatic hyperplasia: 4-year results from the CombAT study. Eur Urol. 2010;57(1):123-31. PubMed
- FDA. Avodart prescribing information. accessdata.fda.gov