Treatment of Yeast Urinary Tract Infections
Fluconazole 200 mg daily for 2 weeks is the first-line treatment for yeast UTIs caused by fluconazole-susceptible Candida species, while amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days or flucytosine 25 mg/kg four times daily for 7-10 days are recommended for fluconazole-resistant species. 1
Treatment Algorithm Based on Candida Species
For Fluconazole-Susceptible Candida Species:
- First-line: Fluconazole 200 mg daily for 2 weeks 1
- Alternative dosing: 200 mg loading dose followed by 100 mg daily for at least 4 days 2
- Fluconazole achieves high urinary concentrations and is available in both oral and intravenous formulations 3, 4
For Fluconazole-Resistant Candida Species (e.g., C. glabrata):
- First option: Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
- Second option: Oral flucytosine 25 mg/kg 4 times daily for 7-10 days 1
- For pyelonephritis: Consider combination therapy with amphotericin B deoxycholate plus flucytosine 1
Important Considerations
Pharmacokinetics
- Echinocandins (e.g., micafungin, caspofungin) achieve poor urinary concentrations and should not be used for uncomplicated fungal UTIs 1, 5
- Newer azoles also fail to achieve adequate urine concentrations 5
- Amphotericin B deoxycholate and flucytosine achieve excellent urinary concentrations 1
Monitoring and Adjustments
- Amphotericin B deoxycholate may require dose adjustment based on renal function with close monitoring for nephrotoxicity 1
- Flucytosine requires significant dose adjustment in renal impairment and drug level monitoring 1
- Flucytosine should not be used as monotherapy due to risk of resistance development 1
Non-Pharmacological Interventions
- Remove indwelling catheters if present (approximately 50% success rate in clearing candiduria) 1, 3
- Address underlying conditions (e.g., diabetes, broad-spectrum antibiotics) 3, 5
Special Situations
Asymptomatic Candiduria
- Treatment is generally not recommended unless the patient is:
Complicated Infections
- For fungal balls or abscesses: Aggressive surgical debridement plus systemic antifungal therapy 1
- Consider local irrigation with amphotericin B (50 mg/L of sterile water) as an adjunct to systemic therapy for complicated cases 1
Follow-up
- Continue treatment until symptoms resolve and urine cultures become negative 1
- Obtain follow-up urine cultures to confirm eradication 1
Common Pitfalls to Avoid
- Using echinocandins or newer azoles for uncomplicated fungal UTIs due to poor urinary concentrations 1, 5
- Treating asymptomatic candiduria unnecessarily 1, 3
- Failing to remove indwelling catheters or address underlying conditions 1
- Using lipid formulations of amphotericin B for lower UTIs (inadequate urine concentrations) 1