How Prostate Weight Affects Medication Choices

Not all BPH medications work equally for all prostate sizes. While alpha-blockers work regardless of size, 5-alpha reductase inhibitors (5-ARIs) are most effective for larger glands. Understanding this relationship helps you and your doctor choose the right medication strategy.

First, calculate your prostate weight using our Weight Calculator.

The Two Main Medication Classes

Alpha-Blockers

Medications: tamsulosin, alfuzosin, silodosin, doxazosin, terazosin

• Mechanism: Relax smooth muscle in prostate and bladder neck
• Onset: Days to weeks
• Size-dependent: No—works for any size prostate

5-Alpha Reductase Inhibitors (5-ARIs)

Medications: finasteride, dutasteride

• Mechanism: Block testosterone conversion, shrinking prostate
• Onset: 6-12 months
• Size-dependent: Yes—most effective for larger glands

Why Size Matters for 5-ARIs

5-ARIs shrink the prostate by 20-30% over time. This shrinkage has more impact on larger glands:

A small prostate shrinking by 6g may not provide noticeable relief. A large prostate shrinking by 25g often does.

Guidelines by Prostate Weight

Small Prostate (<30g)

• First-line: Alpha-blocker alone
• 5-ARI: Generally not recommended (minimal shrinkage benefit)
• Alternative: Consider if symptoms are due to bladder rather than prostate

Medium Prostate (30-40g)

• First-line: Alpha-blocker
• Add 5-ARI if: High PSA (>1.5 ng/mL), family history of BPH progression
• Rationale: Shrinkage benefits begin to become meaningful

Large Prostate (>40g)

• Recommended: Combination therapy (alpha-blocker + 5-ARI)
• Benefits:
  • Immediate symptom relief (alpha-blocker)
  • Long-term shrinkage (5-ARI)
  • Reduced risk of retention and surgery

Additional Size-Based Considerations

PSA Changes with 5-ARIs

5-ARIs reduce PSA by approximately 50% after 6 months. This affects cancer screening:

• Multiply measured PSA by 2 for "true" value
• Any PSA increase on 5-ARI is suspicious
• More relevant for larger glands where 5-ARIs are used

Side Effect Considerations

5-ARIs can cause sexual side effects (decreased libido, erectile dysfunction) in 5-10% of men. For smaller prostates where benefit is minimal, this risk-benefit may not favor 5-ARI use.

The Role of PDE5 Inhibitors

Tadalafil 5mg daily is FDA-approved for BPH:

• Works for any prostate size
• Also treats erectile dysfunction
• Improvement: IPSS reduction of 2-3 points
• May be used alone or with alpha-blockers

Making Your Decision

Information to Gather

1. Calculate your prostate volume
2. Convert to weight with our Weight Calculator
3. Know your current IPSS score (take the quiz)
4. Know your PSA level

Questions for Your Doctor

• What is my prostate weight?
• Am I a candidate for combination therapy?
• What are the realistic expectations for symptom improvement?
• How will medication affect my PSA monitoring?

Summary: Medication by Size

Key Takeaways

Calculate your prostate weight with our Weight Calculator to see which medication strategy fits your situation.