Fluconazole Dosing for Non-Albicans Candida Urinary Tract Infections
For fluconazole-susceptible non-albicans Candida urinary tract infections, use oral fluconazole 200 mg (3 mg/kg) daily for 2 weeks for cystitis, or 200-400 mg (3-6 mg/kg) daily for 2 weeks for pyelonephritis. 1
Critical First Step: Determine Susceptibility and Species
Before initiating fluconazole therapy, you must identify the specific non-albicans species because susceptibility varies dramatically:
- C. parapsilosis and C. tropicalis: Generally fluconazole-susceptible 2
- C. glabrata: Often fluconazole-resistant; only 50% efficacy reported 2
- C. krusei: Intrinsically fluconazole-resistant; do not use fluconazole 1, 2
Dosing Algorithm by Clinical Presentation
For Symptomatic Cystitis (Lower UTI)
Fluconazole-susceptible organisms:
- Oral fluconazole 200 mg (3 mg/kg) daily for 2 weeks 1
- Remove indwelling bladder catheter if present—this is strongly recommended and may resolve candiduria in nearly half of cases without antifungal therapy 1, 3
Fluconazole-resistant C. glabrata:
- Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days, OR 1
- Oral flucytosine 25 mg/kg four times daily for 7-10 days 1, 3
- Consider amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) as adjunctive therapy 1
C. krusei:
For Pyelonephritis (Upper UTI)
Fluconazole-susceptible organisms:
- Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
- Eliminate urinary tract obstruction if present 1
Fluconazole-resistant C. glabrata:
- Amphotericin B deoxycholate 0.5-0.7 mg/kg daily with or without flucytosine 25 mg/kg four times daily for 2 weeks 1
- Flucytosine monotherapy 25 mg/kg four times daily for 2 weeks is an alternative but weaker option 1
C. krusei:
- Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
Special Populations
Dialysis Patients
- For hemodialysis patients with fluconazole-susceptible organisms, administer fluconazole 200 mg after each hemodialysis session 3
- Fluconazole is highly water-soluble and primarily excreted unchanged in urine, requiring dose adjustment in renal failure 4
High-Risk Patients Requiring Treatment
Even asymptomatic candiduria requires treatment in:
- Neutropenic patients (treat as candidemia) 1
- Very low birth weight infants <1500g (treat as candidemia) 1
- Patients undergoing urologic procedures: fluconazole 400 mg (6 mg/kg) daily for several days before and after the procedure 1
Common Pitfalls and How to Avoid Them
Pitfall #1: Using fluconazole for C. krusei
- C. krusei is intrinsically resistant to fluconazole 1, 2
- Always use amphotericin B for C. krusei infections 1
Pitfall #2: Inadequate dosing for C. glabrata
- C. glabrata has reduced fluconazole susceptibility with only 50% efficacy 2
- Higher doses may be required, but amphotericin B or flucytosine are preferred alternatives 1
Pitfall #3: Treating asymptomatic candiduria unnecessarily
- Treatment is NOT recommended for asymptomatic candiduria unless the patient is high-risk 1
- Simply removing the catheter resolves candiduria in many cases 1, 3
Pitfall #4: Continuing indwelling catheters during treatment
- Catheter removal is strongly recommended and significantly improves cure rates 1, 3
- Failure to remove catheters is a major cause of treatment failure 3
Pitfall #5: Insufficient treatment duration
Evidence Quality Considerations
The IDSA guidelines provide strong recommendations (strong recommendation; moderate-quality evidence for fluconazole-susceptible cystitis) 1, though most recommendations for non-albicans species are based on low-quality evidence 1. The 2016 IDSA guidelines are the most authoritative source and supersede the 2009 guidelines 1. Clinical studies demonstrate 77% overall efficacy for fluconazole against non-albicans species, with 93% efficacy for C. parapsilosis but only 50% for C. glabrata 2.