Can you take Flomax (tamsulosin) with dutasteride?

Taking Flomax (Tamsulosin) with Dutasteride

Yes, you can take Flomax (tamsulosin) with dutasteride, and this combination is actually recommended for patients with symptomatic benign prostatic hyperplasia (BPH) who have demonstrable prostatic enlargement. 1

Evidence for Combination Therapy

• Combination therapy with tamsulosin (an alpha blocker) and dutasteride (a 5-alpha reductase inhibitor or 5-ARI) is a well-established treatment approach for BPH, working on the premise that each medication targets a different site in the lower urinary tract 1
• The American Urological Association (AUA) strongly recommends 5-ARI in combination with an alpha blocker for patients with LUTS associated with demonstrable prostatic enlargement (prostate volume >30cc on imaging, PSA >1.5ng/mL, or palpable prostate enlargement on digital rectal examination) 1
• Two major studies, Medical Therapy of Prostatic Symptoms (MTOPS) and Combination of Avodart and Tamsulosin (CombAT), showed statistically significant reductions in parameters of clinical progression with combination approaches over monotherapy 1

Benefits of Combination Therapy

• The 4-year CombAT study demonstrated that combination therapy with dutasteride and tamsulosin provides significantly greater symptom improvement than either medication alone 2
• Combination therapy significantly reduced the risk of acute urinary retention (AUR) and BPH-related surgery compared to tamsulosin monotherapy 2
• The combination provides better long-term control of both storage and voiding lower urinary tract symptoms compared to tamsulosin monotherapy 3
• Health-related quality of life and treatment satisfaction were improved to a significantly greater extent with dutasteride plus tamsulosin than with either agent alone 4

Side Effects and Considerations

• The most common adverse reactions with combination therapy include impotence, decreased libido, breast disorders (including breast enlargement and tenderness), ejaculation disorders, and dizziness 5
• Ejaculation disorders occur significantly more frequently in patients receiving combination therapy (11%) compared with those receiving dutasteride (2%) or tamsulosin (4%) as monotherapy 5
• Tamsulosin is associated with intraoperative floppy iris syndrome during cataract surgery, which should be considered if ophthalmic procedures are planned 6
• Dutasteride reduces serum PSA levels by approximately 50%, which should be considered when screening for prostate cancer 1

Treatment Algorithm

1. Patient Assessment:

   • Determine prostate size (>30cc on imaging, PSA >1.5ng/mL, or palpable enlargement on DRE) 1
   • Assess symptom severity using validated tools like IPSS 1

2. Treatment Selection:

   • For patients with moderate-to-severe LUTS and enlarged prostate: combination therapy is appropriate 1
   • For patients with smaller prostates or mild symptoms: monotherapy may be sufficient 1

3. Monitoring:

   • Follow-up to assess symptom improvement and medication tolerability 1
   • For patients on dutasteride, double the measured PSA value after 1 year of therapy to accurately gauge disease progression 1

Important Caveats

• Combination therapy should be reserved for patients with demonstrable prostatic enlargement, as this population benefits most from the addition of a 5-ARI 1
• The onset of action differs between medications - alpha blockers like tamsulosin provide relatively rapid symptom relief, while 5-ARIs like dutasteride have a slower onset but provide long-term benefits in reducing prostate size and disease progression 1
• Trial withdrawal due to adverse reactions occurs in approximately 6% of patients receiving combination therapy, with erectile dysfunction being the most common reason (1% to 1.5%) 5