What is the comparison between Tamsulosin (alpha-blocker) and Dutasteride (5-alpha-reductase inhibitor)?

From the Guidelines

For patients with moderate to severe benign prostatic hyperplasia (BPH) symptoms and enlarged prostates, combination therapy with dutasteride and tamsulosin is superior to monotherapy with either medication alone, reducing the risk of acute urinary retention (AUR) and the need for surgery by 68% and 71%, respectively. The choice between tamsulosin and dutasteride depends on the patient's specific needs, with tamsulosin providing quicker relief of urinary symptoms and dutasteride offering long-term reduction of prostate size 1. Some key points to consider when deciding between these medications include:

• Tamsulosin is an alpha-blocker that relaxes smooth muscles in the prostate and bladder neck, providing relatively quick relief of urinary symptoms 1.
• Dutasteride is a 5-alpha reductase inhibitor that shrinks the prostate by blocking testosterone conversion to dihydrotestosterone, taking 3-6 months to reach full effectiveness 1.
• Combination therapy with dutasteride and tamsulosin has been shown to reduce clinical progression risk by 66% versus placebo, 34% versus finasteride, and 39% versus doxazosin 1.
• The number needed to treat with combination therapy to prevent one case of urinary retention and/or surgical treatment is 13 patients over 4 years 1. Potential side effects of these medications should also be considered, including dizziness, retrograde ejaculation, and orthostatic hypotension with tamsulosin, and sexual dysfunction, breast tenderness, and the need for PSA monitoring with dutasteride 1.

From the FDA Drug Label

Statistically significant differences (dutasteride versus placebo) were noted at the earliest post-treatment prostate volume measurement in each trial (Month 1, Month 3, or Month 6) and continued through Month 24. The efficacy of combination therapy (dutasteride 0.5 mg/day plus tamsulosin 0. 4 mg/day, n = 1,610) was compared with dutasteride alone (n = 1,623) or tamsulosin alone (n = 1,611) in a 4-year multicenter, randomized, double-blind trial. At Month 24 the mean changes from baseline (±SD) in IPSS total symptom scores were -6.2 (±7.14) for combination, -4.9 (±6.81) for dutasteride, and -4.3 (±7. 01) for tamsulosin, with a mean difference between combination and dutasteride of -1.3 units (P <0.001; [95% CI: -1.69, -0.86]), and between combination and tamsulosin of -1.8 units (P <0.001; [95% CI: -2.23, -1.40]). At Month 24, the mean increases from baseline (±SD) in Qmax were 2.4 (±5.26) mL/sec for combination, 1.9 (±5. 10) mL/sec for dutasteride, and 0.9 (±4.57) mL/sec for tamsulosin, with a mean difference between combination and dutasteride of 0.5 mL/sec (P = 0.003; [95% CI: 0.17,0.84]), and between combination and tamsulosin of 1.5 mL/sec (P <0.001; [95% CI: 1.19,1. 86]).

Comparison of Tamsulosin and Dutasteride:

• Symptom Score: Combination therapy with dutasteride and tamsulosin was statistically superior to each of the monotherapy treatments in decreasing symptom score at Month 24.
• Maximum Urine Flow Rate (Qmax): Combination therapy was statistically superior to each of the monotherapy treatments in increasing Qmax at Month 24.
• Prostate Volume: The mean percent changes from baseline in prostate volume were -26.9% for combination therapy and -28% for dutasteride at Month 24. The combination of dutasteride and tamsulosin provides additional benefits over monotherapy with either drug in terms of symptom score and Qmax, but not in reducing the incidence of AUR or BPH-related surgery 2.

From the Research

Comparison of Tamsulosin and Dutasteride

• Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D )-adrenoceptor antagonist, which relaxes prostate and bladder smooth muscles, improving maximal urine flow and alleviating lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH) 3.
• Dutasteride is a 5α-reductase inhibitor that reduces prostate size and prevents disease progression in longer-term treatment 4, 5.
• The Combination of Avodart and Tamsulosin (CombAT) trial showed that combination therapy with dutasteride and tamsulosin improved LUTS to a significantly greater extent than dutasteride or tamsulosin alone in men with BPH, moderate to severe LUTS, and an increased risk of disease progression 4, 5.
• The Medical Therapy of Prostatic Symptoms (MTOPS) study found that combination therapy with the alpha(1)ARA doxazosin and the 5ARI finasteride was significantly more effective than either component alone in reducing BPH-related symptoms and lowering the rate of overall clinical progression 6.

Efficacy and Safety

• Tamsulosin 0.4 mg once daily was effective in patients with mild to severe LUTS associated with BPH, and did not interfere with concomitant antihypertensive therapy 3.
• Dutasteride 0.5 mg/day plus tamsulosin 0.4 mg/day improved health-related quality of life and treatment satisfaction to a significantly greater extent than dutasteride or tamsulosin alone 4.
• Combination therapy with dutasteride and tamsulosin was generally well tolerated in patients with symptomatic BPH 4.

Patient Selection

• Patients with larger prostates and higher prostate-specific antigen (PSA) levels are at greater risk of BPH progression and may benefit from combination therapy 5, 6.
• The final decision about the best treatment for a particular patient should take into account the patient's preference after they have been informed of the different options 7.