What are the next steps for a patient with breakthrough urinary symptoms on finasteride after discontinuing tamsulosin due to orthostatic hypotension?

Management of Breakthrough Urinary Symptoms After Tamsulosin Discontinuation

For a patient with breakthrough urinary symptoms on finasteride after discontinuing tamsulosin due to orthostatic hypotension, the next step should be to try alfuzosin as an alternative alpha-blocker with a lower risk of orthostatic hypotension. 1

Rationale for Alpha-Blocker Selection

Alpha-blockers remain the first-line treatment for LUTS due to their rapid onset of action and good efficacy. However, the patient's previous experience with orthostatic hypotension requires careful selection:

• Alfuzosin is the preferred next option because:

  • It has similar efficacy to tamsulosin for LUTS relief 1
  • It has a lower probability of orthostatic hypotension than other alpha-blockers 1
  • It does not have the higher ejaculatory dysfunction risk associated with tamsulosin 1

• Silodosin could be considered as an alternative if alfuzosin is not tolerated, as it has:

  • Selective alpha-1A receptor antagonism
  • Lower risk of orthostatic hypotension
  • Higher risk of ejaculatory dysfunction (which may be acceptable if hypotension is the primary concern) 1

Treatment Algorithm

1. First attempt: Alfuzosin

   • Start with 10mg once daily with food
   • Monitor for orthostatic hypotension during the first few doses
   • Evaluate efficacy after 2-4 weeks

2. If alfuzosin causes orthostatic hypotension:

   • Consider silodosin (8mg once daily) with lower cardiovascular effects but higher sexual side effects
   • OR consider non-alpha blocker alternatives (see below)

3. If alpha-blockers cannot be tolerated:

   • Continue finasteride (already prescribed)
   • Add antimuscarinic agent if storage symptoms predominate and PVR <150ml 1
   • Consider beta-3 agonist (mirabegron) for storage symptoms with lower risk of orthostatic effects 1
   • Consider PDE5 inhibitor (tadalafil) which may improve LUTS without orthostatic effects 1

4. If medical therapy fails:

   • Consider surgical intervention (TURP, laser procedures, minimally invasive options)

Important Considerations

• Maintain finasteride therapy throughout these changes as it reduces prostate size and risk of disease progression, especially if prostate volume >40ml 1

• Avoid combination of alpha-blockers with PDE5 inhibitors as this can significantly increase the risk of dangerous hypotension 2

• Monitor for orthostatic hypotension by checking blood pressure in both lying and standing positions, especially with the first few doses of any new alpha-blocker

• Dosing time may be important - taking alpha-blockers at bedtime can minimize symptomatic orthostatic hypotension during daytime activities

• Hydration status should be optimized, but excessive fluid intake before bedtime should be avoided to minimize nocturia

Pitfalls to Avoid

1. Don't discontinue finasteride - it takes 3-6 months for full effect and works well for long-term management, especially with enlarged prostates 3

2. Don't use doxazosin or terazosin as they have higher rates of orthostatic hypotension compared to alfuzosin or silodosin 1

3. Don't combine alpha-blockers with other antihypertensive medications without careful blood pressure monitoring 1

4. Don't assume all alpha-blockers have the same side effect profile - there are important differences in selectivity and cardiovascular effects 1

5. Don't overlook the possibility of urinary retention - if symptoms worsen rapidly, check post-void residual volume

By following this approach, the patient's breakthrough urinary symptoms can be managed while minimizing the risk of orthostatic hypotension that previously led to tamsulosin discontinuation.