Management of Concurrent PDE5 Inhibitor Use
Do not combine vardenafil with tadalafil—discontinue the tadalafil 5 mg daily and use vardenafil 20 mg as needed for erectile dysfunction, or continue tadalafil 5 mg daily alone if it adequately addresses both BPH symptoms and erectile dysfunction. Combining two PDE5 inhibitors is contraindicated due to increased risk of adverse effects including hypotension, and offers no therapeutic advantage 1, 2.
Clinical Decision Algorithm
Step 1: Assess Current Symptom Control
- If tadalafil 5 mg daily is adequately controlling both LUTS/BPH and erectile dysfunction: Continue tadalafil alone and do not add vardenafil 2, 3, 4
- If erectile dysfunction remains inadequately treated: Consider switching strategies rather than combining agents 1
Step 2: Choose Single-Agent Strategy
Option A: Continue Tadalafil Monotherapy (Preferred for dual indication)
- Tadalafil 5 mg once daily treats both BPH and ED effectively, with 69% of men reporting improved erections versus 33% with placebo 2, 4
- This dose is FDA-approved and guideline-recommended for BPH treatment 2
- Provides spontaneous sexual activity without timing medication 5
- Well-tolerated for up to 1 year with mild-to-moderate adverse effects 3
Option B: Switch to Vardenafil for ED Only
- Discontinue tadalafil completely before starting vardenafil 1
- Vardenafil 20 mg as needed shows dose-dependent efficacy (68% successful intercourse vs 35% placebo) 1
- Requires alternative BPH management (alpha-blocker monotherapy) 1
- Critical caveat: Do not combine vardenafil with alpha-blockers initially—use caution and start alpha-blocker separately with appropriate monitoring 6
Key Safety Considerations
Absolute Contraindications
- Never combine two PDE5 inhibitors simultaneously—this increases adverse effects without improving efficacy 1, 7
- All PDE5 inhibitors are contraindicated with nitrate use due to severe hypotension risk 7, 6
- Vardenafil specifically contraindicated with Class 1A or Class 3 antiarrhythmics 6
Important Drug Interactions
- Exercise caution with CYP3A4 inhibitors (azole antifungals, protease inhibitors, macrolide antibiotics) as they increase PDE5 inhibitor levels 6
- Alpha-blockers can be used with PDE5 inhibitors but require precaution, not absolute contraindication as previously thought 6
- However, combining tadalafil 5 mg daily with alpha-blockers for BPH offers no advantage over either agent alone 1, 2
Common Pitfalls to Avoid
- Polypharmacy error: Adding vardenafil to existing tadalafil without discontinuing the first agent 1
- Inadequate trial period: Patients may require multiple attempts with proper sexual stimulation before declaring treatment failure 7
- Timing issues: Large meals can impair PDE5 inhibitor absorption—counsel patients on proper administration 7
- Unrealistic expectations: Men with diabetes or post-prostatectomy may respond less robustly to any PDE5 inhibitor 5
Practical Implementation
Most appropriate approach for this patient: Continue tadalafil 5 mg daily alone, as it addresses both his BPH (original indication) and erectile dysfunction 2, 3, 4. If ED symptoms remain inadequately controlled after ensuring proper use (sexual stimulation, multiple trials, appropriate timing), then consider discontinuing tadalafil and switching to vardenafil 20 mg as needed—but never use both concurrently 1.