Amphotericin B Bladder Irrigation Protocol
For fungal cystitis caused by fluconazole-resistant species (particularly C. glabrata and C. krusei), use amphotericin B deoxycholate bladder irrigation at 50 mg/L in sterile water, administered continuously over 24 hours daily for 5 days. 1
When to Use Bladder Irrigation
Amphotericin B bladder irrigation is specifically indicated for:
- Fluconazole-resistant fungal cystitis (C. glabrata or C. krusei) 1
- Patients with indwelling urinary catheters who have failed or cannot receive systemic therapy 1
- As an adjunct to systemic therapy in refractory cases
Critical caveat: This is a weak recommendation with low-quality evidence from IDSA guidelines. Bladder irrigation should NOT be first-line therapy—systemic antifungals remain preferred when feasible 1.
Dosing Protocol
Standard Regimen (IDSA 2016 Guidelines)
- Concentration: 50 mg amphotericin B per liter of sterile water 1
- Duration: Daily for 5 days 1
- Administration: Continuous bladder irrigation over 24 hours
Evidence-Based Considerations
Concentration matters: A randomized trial demonstrated 100% eradication with 50 mg/L versus only 67% with 10 mg/L 2. The study was stopped early because all treatment failures occurred in the lower-dose group. Do not use concentrations below 50 mg/L.
Continuous vs. intermittent: Continuous irrigation (50 mg/L over 24 hours) achieved 80% eradication compared to only 30% with intermittent irrigation 3. Continuous administration is superior in efficacy, ease of use, and patient comfort.
Administration Technique
- Change the urinary catheter to a three-way catheter before initiating irrigation 2, 4
- Prepare solution: 50 mg amphotericin B in 1 liter sterile water 5
- Infuse continuously at approximately 42 mL/hour over 24 hours 2
- Repeat daily for 5 consecutive days 1
- Remove or replace the catheter after completing therapy if feasible 1
Alternative Approach (If Continuous Irrigation Not Feasible)
If continuous irrigation is impractical, consider:
- 200-300 mL of amphotericin B solution (5-10 mg/L) via triple-lumen catheter
- Cross-clamp for 60-90 minutes "dwell time"
- Duration: no longer than 2 days 6
Note: This approach has weaker evidence and lower efficacy than continuous irrigation.
Nephrostomy Tube Irrigation (Fungal Balls/Pyelonephritis)
For fungal balls or upper tract involvement with nephrostomy tubes in place:
- Dose: 25-50 mg amphotericin B in 200-500 mL sterile water 1
- Irrigate through the nephrostomy tube
- Strong recommendation from IDSA guidelines 1
Safety Profile
Bladder irrigation is remarkably safe compared to systemic amphotericin B:
- No significant nephrotoxicity observed in recent studies 5
- Minimal systemic absorption
- Adverse effects limited to mild catheter-related discomfort 5
- No increase in serum creatinine levels 5
Critical warning: Never confuse bladder irrigation dosing with systemic IV dosing. Systemic amphotericin B has a maximum dose of 1.5 mg/kg/day, and overdoses can cause fatal cardiac arrest 7.
Efficacy Expectations
- Eradication rates: 75-82% at 5-9 days post-therapy 4
- Comparable to oral fluconazole for susceptible organisms 4
- Superior for resistant species where fluconazole is not an option 1
- Recent data shows 66% candiduria eradication in high-risk elderly patients with resistant organisms 5
Essential Concurrent Measures
Always address these factors to maximize success:
- Remove indwelling bladder catheter if feasible (strong recommendation) 1
- Eliminate urinary tract obstruction (strong recommendation) 1
- Consider removal/replacement of nephrostomy tubes or stents if present 1
- Optimize diabetes control in diabetic patients 1
When NOT to Use Bladder Irrigation
- Asymptomatic candiduria in non-high-risk patients (treatment not recommended) 1
- Fluconazole-susceptible organisms (use oral fluconazole 200 mg daily for 2 weeks instead) 1
- Candidemia or systemic infection (requires systemic therapy) 1
- Pyelonephritis without catheter/tube (use systemic therapy) 1