What is the recommended dosing of fluconazole (Fluconazole) for the treatment of yeast in a Urinary Tract Infection (UTI)?

Fluconazole Dosing for Yeast in Urinalysis

For fluconazole-susceptible Candida species causing symptomatic urinary tract infection, administer 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, and remove any indwelling bladder catheter immediately. 1

Treatment Algorithm Based on Clinical Presentation

Step 1: Determine if Treatment is Indicated

• Asymptomatic candiduria does NOT require treatment in most patients, as treatment does not improve mortality or outcomes 1
• Treat only if: neutropenic, very low birth weight infant (<1500g), or undergoing urologic instrumentation within 48-72 hours 1, 2
• Remove indwelling catheter immediately if present—this alone resolves candiduria in approximately 50% of cases and is the single most important intervention 1, 3

Step 2: Identify the Site of Infection

For Cystitis (Lower UTI):

• Fluconazole 200 mg (3 mg/kg) orally daily for 14 days 1, 2
• This is a strong recommendation with moderate-quality evidence from the Infectious Diseases Society of America 1

For Pyelonephritis (Upper UTI):

• Fluconazole 200-400 mg (3-6 mg/kg) orally daily for 14 days 1, 2
• Use the higher dose (400 mg) for more severe presentations or complicated infections 1

Step 3: Adjust for Renal Dysfunction

For hemodialysis patients:

• Administer fluconazole 200 mg after each hemodialysis session rather than daily dosing 2, 3
• Do NOT use standard daily dosing as fluconazole is dialyzable and therapeutic levels will not be maintained 3

For continuous ambulatory peritoneal dialysis:

• Fluconazole 50 mg intraperitoneally or 100 mg orally has been used successfully 4

Species-Specific Considerations

Fluconazole-Susceptible Species (C. albicans, most C. parapsilosis)

• Use the dosing outlined above 1, 2
• These species typically have MIC90 values of 12-16 mcg/mL for fluconazole 5

Fluconazole-Resistant C. glabrata

• Do NOT use fluconazole 1, 2
• Use amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days OR oral flucytosine 25 mg/kg four times daily for 7-10 days 1, 2
• C. glabrata has MIC90 of 64 mcg/mL, indicating resistance 5

C. krusei (Intrinsically Fluconazole-Resistant)

• Do NOT use fluconazole 1, 2
• Use amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1, 2

Critical Pitfalls to Avoid

Catheter Management:

• Continuing treatment without removing an indwelling catheter is the most common cause of treatment failure 3
• Catheter removal is a strong recommendation from the Infectious Diseases Society of America and significantly improves cure rates 2, 3

Duration Errors:

• While recent data suggest shorter courses (median 7 days) may be non-inferior to 14 days for clinical success 6, the Infectious Diseases Society of America guidelines strongly recommend 14 days to minimize relapse risk 1, 2
• Shorter courses lead to higher recurrence rates, particularly in immunocompromised patients 2, 4

Species Identification:

• Always obtain species identification and susceptibility testing before finalizing therapy 3
• Empiric fluconazole will fail with C. glabrata (10-30% of candiduria cases) and C. krusei 2, 3
• Assuming all yeast is fluconazole-susceptible leads to treatment failures 3

Treating Asymptomatic Candiduria:

• Reflexive treatment of asymptomatic candiduria leads to unnecessary antifungal exposure and resistance development without improving outcomes 1, 3
• Even in renal transplant recipients, treatment of asymptomatic candiduria does not improve mortality 1

Monitoring and Follow-Up

Clinical Response Assessment:

• Monitor for symptom resolution within 3-5 days of initiating therapy 3
• If no improvement occurs, repeat urine culture to assess for fluconazole resistance, particularly with C. glabrata 3

Imaging Considerations:

• Perform renal ultrasound or CT if symptoms persist to evaluate for urinary tract obstruction, fungal balls, or emphysematous pyelonephritis 1
• These complications require surgical intervention in addition to antifungal therapy 1, 3

Recurrence Prevention:

• Address underlying risk factors: diabetes control, immunosuppression, urinary stasis, and structural abnormalities 1
• Eliminate urinary tract obstruction if present—this is a strong recommendation from the Infectious Diseases Society of America 1