What alternative medication can be used for a patient with Benign Prostatic Hyperplasia (BPH) currently on Flomax (tamsulosin) twice daily (bid) who has positive orthostatic hypotension?

Alternative Medications for BPH with Orthostatic Hypotension

For a patient with BPH currently on Flomax (tamsulosin) twice daily who has positive orthostatic hypotension, 5-alpha reductase inhibitors (finasteride or dutasteride) are the preferred alternative medications as they do not cause orthostatic hypotension and are effective for long-term management, particularly in men with enlarged prostates (>30cc). 1

Why Alpha Blockers Cause Orthostatic Hypotension

Alpha blockers (including tamsulosin, doxazosin, terazosin, and alfuzosin) work by blocking alpha-1 receptors in the prostate and blood vessels. While effective for BPH symptoms, they commonly cause:

• Orthostatic hypotension
• Dizziness
• Tiredness (asthenia)
• Ejaculatory problems
• Nasal congestion 2

Even tamsulosin, which is considered more "uroselective," can still cause orthostatic hypotension, particularly when used at higher doses or twice daily as in this patient's case.

5-Alpha Reductase Inhibitors: The Preferred Alternative

Mechanism and Benefits:

• Inhibit conversion of testosterone to dihydrotestosterone (DHT)
• Reduce prostate size by 20-30%
• Do not affect blood pressure or cause orthostatic hypotension
• Particularly effective for enlarged prostates (>30cc)
• Reduce risk of disease progression 1, 3

Specific Options:

1. Finasteride (5mg daily):

   • Reduces risk of acute urinary retention by 67%
   • Reduces need for BPH-related surgery by 64%
   • Improves AUA Symptom Index by approximately 3 points 4

2. Dutasteride:

   • Reduces serum DHT by approximately 95%
   • Reduces prostate tissue DHT by approximately 94%
   • Similar efficacy profile to finasteride 1

Important Considerations:

• Takes 3-6 months for full clinical effect (unlike alpha blockers which work within days)
• Most effective in men with enlarged prostates
• Side effects include sexual dysfunction (decreased libido, ejaculatory disorders)
• Not appropriate for men without evidence of prostatic enlargement 2, 4

Alternative Alpha Blocker Options

If continuing with an alpha blocker is preferred, consider:

1. Alfuzosin (10mg once daily):

   • Clinically "uroselective" despite not being receptor subtype selective
   • Less likely to cause significant orthostatic hypotension than other alpha blockers
   • Should be taken with food and at bedtime to minimize orthostatic effects 1, 5

2. Silodosin (8mg once daily):

   • Highly selective for alpha-1A receptors in the prostate
   • Lower risk of orthostatic hypotension
   • Higher risk of ejaculatory dysfunction 1

Other Medication Options

1. PDE-5 Inhibitors:

   • Tadalafil 5mg daily can improve BPH symptoms
   • Particularly useful if patient also has erectile dysfunction
   • Should not be combined with alpha blockers due to risk of hypotension 1

2. Beta-3-agonists (Mirabegron):

   • May be offered for storage symptoms
   • Can be used in combination with 5-ARIs
   • Does not cause orthostatic hypotension 1

Treatment Algorithm

1. First-line: Switch to finasteride 5mg daily or dutasteride 0.5mg daily

   • Especially if prostate is enlarged (>30cc)
   • Monitor for 3-6 months for clinical effect
   • No dose adjustment needed for orthostatic hypotension

2. If storage symptoms predominate or 5-ARIs insufficient:

   • Consider adding mirabegron or switching to alfuzosin (taken at bedtime)
   • Monitor blood pressure closely after initiating

3. If inadequate response after 6 months:

   • Consider combination therapy with 5-ARI and carefully titrated alpha blocker
   • Consider surgical options if medical therapy fails

Follow-up Recommendations

• Evaluate 4-12 weeks after initiating treatment
• Assess symptom improvement using IPSS score
• Measure post-void residual volume
• Monitor for medication side effects
• Regular PSA monitoring (note that 5-ARIs reduce PSA by approximately 50%)

Remember that 5-ARIs take longer to work than alpha blockers but provide long-term benefits including reduced risk of acute urinary retention and need for surgery, without the risk of orthostatic hypotension 1, 4, 6.