What are the best medications for benign prostatic hyperplasia (BPH), such as tamsulosin and finasteride?

Best Medications for Benign Prostatic Hyperplasia

For men with moderate-to-severe BPH symptoms and an enlarged prostate (>30cc), combination therapy with tamsulosin 0.4 mg and a 5-alpha-reductase inhibitor (dutasteride or finasteride) is the most effective treatment to improve symptoms and prevent disease progression. 1, 2

Treatment Selection Algorithm

Step 1: Assess Prostate Size and Symptom Severity

• Confirm prostatic enlargement using one of the following criteria: 2
  • Prostate volume >30cc on imaging, OR
  • PSA >1.5 ng/mL, OR
  • Palpable prostate enlargement on digital rectal examination
• Assess symptom severity using validated tools (AUA Symptom Score >8 indicates moderate-to-severe symptoms) 3

Step 2: Choose Therapy Based on Prostate Size

For enlarged prostates (>30cc) with moderate-to-severe symptoms:

• Initiate combination therapy with tamsulosin 0.4 mg daily plus either dutasteride 0.5 mg or finasteride 5 mg daily 1, 2
• Combination therapy reduces overall BPH clinical progression by 67% compared to 39% for alpha-blockers alone and 34% for 5-alpha-reductase inhibitors alone 1
• The best-tested combination is doxazosin and finasteride, though the combination of any effective alpha-blocker and 5-alpha-reductase inhibitor likely produces comparable benefit 3

For smaller prostates (<30cc) with moderate-to-severe symptoms:

• Use tamsulosin monotherapy 0.4 mg once daily 4, 5
• Alpha-blockers do not reduce prostate size and should not be used for this purpose 4
• 5-alpha-reductase inhibitors are ineffective in patients without prostatic enlargement 1

Medication-Specific Considerations

Tamsulosin (Alpha-Blocker)

• Standard dose: 0.4 mg once daily, no titration required 4
• Onset of action: Rapid symptom relief (within days to weeks) 2
• Efficacy: Improves symptoms by 12% and increases peak urine flow by 1.1 mL/sec compared to placebo 6
• Does not reduce prostate size 4

Finasteride (5-Alpha-Reductase Inhibitor)

• FDA-approved indications: 7
  • Monotherapy for symptomatic BPH to improve symptoms, reduce acute urinary retention risk, and reduce need for surgery
  • Combination with alpha-blocker (specifically doxazosin) to reduce symptomatic progression
• Onset of action: Slower (3-6 months for noticeable improvement) 1
• Reduces prostate volume and PSA levels by approximately 50% after 1 year 1, 2

Dutasteride (Dual 5-Alpha-Reductase Inhibitor)

• More potent than finasteride: Reduces serum DHT by ~95% vs ~70% with finasteride 1
• Reduces prostate volume by 15-25% after 6 months 1
• Reduces clinical progression: 21% vs 36% with placebo (includes AUR, UTI, or need for surgery) 1
• Sustained long-term benefit maintained for 6-10 years 1

Critical Timing Considerations

Combination therapy provides additive benefits with different time courses: 2

• Tamsulosin provides relatively rapid symptom relief (weeks)
• 5-alpha-reductase inhibitors provide slower onset but long-term benefits in reducing prostate size and preventing progression (months)

This dual mechanism explains why combination therapy is superior to either monotherapy alone in men with enlarged prostates 8, 9

Important Safety Warnings and Pitfalls

Before Starting Tamsulosin:

• Inform ophthalmologists if patient is planning cataract or glaucoma surgery due to risk of intraoperative floppy iris syndrome 1, 4, 5
• Higher risk of ejaculatory dysfunction compared to other alpha-blockers 4
• Risk of orthostatic hypotension, especially after first dose 5

Before Starting 5-Alpha-Reductase Inhibitors:

• Counsel patients that PSA levels will decrease by ~50% after 1 year of therapy 1, 2
• Double the measured PSA value after 1 year of therapy when screening for prostate cancer 1, 2
• Sexual side effects including decreased libido, erectile dysfunction, and ejaculatory disorders occur more frequently than with placebo 7
• Not approved for prostate cancer prevention 7

Common Pitfall to Avoid:

Do not use combination therapy in patients without prostatic enlargement - this exposes patients to unnecessary side effects without benefit, as 5-alpha-reductase inhibitors are ineffective in smaller prostates 1

Adverse Effects Profile

Combination Therapy (from MTOPS trial):

The most common adverse effects with combination therapy include: 7

• Abnormal ejaculation: 14.1% (vs 2.3% placebo)
• Impotence: 22.6% (vs 12.2% placebo)
• Decreased libido: 11.6% (vs 5.7% placebo)
• Dizziness: 23.2% (vs 8.1% placebo)
• Postural hypotension: 17.8% (vs 8.0% placebo)

The incidence of abnormal ejaculation with combination therapy was comparable to the sum of incidences from both monotherapies 7