What is the recommended dosing regimen for fluconazole (antifungal medication) in the treatment of candidiasis?

Fluconazole Dosing for Candidiasis

Fluconazole dosing varies by site and severity of candidiasis: for oropharyngeal candidiasis use 100-200 mg daily for 7-14 days; for esophageal candidiasis use 200-400 mg daily for 14-21 days; for candidemia use a loading dose of 800 mg then 400 mg daily; and for vaginal candidiasis use a single 150 mg dose. 1, 2

Oropharyngeal Candidiasis

Mild Disease

• Topical therapy is first-line: clotrimazole troches 10 mg 5 times daily for 7-14 days 1
• Alternative: nystatin suspension 100,000 U/mL at 4-6 mL 4 times daily for 7-14 days 1

Moderate to Severe Disease

• Oral fluconazole 100-200 mg (3 mg/kg) daily for 7-14 days 1
• FDA-approved regimen: 200 mg on day 1, then 100 mg daily for at least 2 weeks 2
• Continue treatment for minimum 2 weeks even if symptoms resolve earlier to reduce relapse risk 3, 2

Fluconazole-Refractory Disease

• Itraconazole solution 200 mg daily 1
• Posaconazole suspension 400 mg twice daily for 3 days, then 400 mg daily for up to 28 days 1
• Voriconazole 200 mg twice daily if other agents fail 1

Chronic Suppressive Therapy

• Fluconazole 100 mg three times weekly for recurrent infections in immunocompromised patients 1, 3
• This is typically unnecessary for HIV patients on effective antiretroviral therapy 1

Esophageal Candidiasis

Initial Treatment

• Fluconazole 200-400 mg (3-6 mg/kg) daily for 14-21 days 1
• FDA-approved regimen: 200 mg on day 1, then 100 mg daily (up to 400 mg daily based on response) 2
• Treat for minimum 3 weeks and at least 2 weeks after symptom resolution 2
• Systemic therapy is always required; topical agents are inadequate 1

Intravenous Therapy

• IV fluconazole 400 mg (6 mg/kg) daily for patients unable to tolerate oral therapy 1

Refractory Disease

• Itraconazole solution 200 mg daily for 14-21 days 1
• Posaconazole suspension 400 mg twice daily for 14-21 days 1
• Voriconazole 200 mg twice daily (IV or oral) for 14-21 days 1
• Echinocandins (micafungin 150 mg daily, caspofungin 50 mg daily, or anidulafungin 200 mg daily) 1

Suppressive Therapy

• Fluconazole 100-200 mg three times weekly for recurrent infections 1, 3

Candidemia and Invasive Candidiasis

Initial Therapy

• Loading dose: fluconazole 800 mg (12 mg/kg) on day 1, then 400 mg (6 mg/kg) daily 1
• Alternative: echinocandins are preferred for moderately severe to severe illness, recent azole exposure, or suspected C. glabrata or C. krusei 1
  • Caspofungin: 70 mg loading dose, then 50 mg daily 1
  • Micafungin: 100 mg daily 1
  • Anidulafungin: 200 mg loading dose, then 100 mg daily 1

Species-Specific Considerations

• For C. albicans: Fluconazole is appropriate for clinically stable patients without recent azole exposure 1
• For C. glabrata: Echinocandin is preferred; do not transition to fluconazole without susceptibility confirmation 1
• For C. parapsilosis: Fluconazole is preferred over echinocandins 1
• For C. krusei: Use echinocandin, lipid formulation amphotericin B, or voriconazole (fluconazole is intrinsically resistant) 1

Duration

• Continue for 2 weeks after documented clearance from bloodstream and resolution of symptoms 1
• Catheter removal is strongly recommended for nonneutropenic patients 1, 3

Vaginal Candidiasis

Acute Infection

• Single oral dose of fluconazole 150 mg 2, 4
• Clinical cure rate of 88-97% at follow-up 5, 4

Recurrent Vulvovaginal Candidiasis

• Induction: fluconazole 150 mg every 72 hours for 3 doses 6
• Maintenance: fluconazole 150 mg weekly for 6 months 6
• This regimen reduces recurrence from 57% to 10% at 6 months 6

Urinary Tract Candidiasis

• Fluconazole 200 mg daily for 2 weeks for fluconazole-susceptible organisms 3
• Treatment only indicated for high-risk groups: neutropenic patients, very low birth weight infants, or patients undergoing urologic procedures 3, 7
• For urologic procedures: 400 mg daily for several days before and after the procedure 3

Pediatric Dosing

General Equivalency

• 3 mg/kg pediatric dose = 100 mg adult dose 2
• 6 mg/kg pediatric dose = 200 mg adult dose 2
• 12 mg/kg pediatric dose = 400 mg adult dose (maximum 600 mg/day) 2

Oropharyngeal Candidiasis

• 6 mg/kg on day 1, then 3 mg/kg daily for at least 2 weeks 2

Esophageal Candidiasis

• 6 mg/kg on day 1, then 3 mg/kg daily (up to 12 mg/kg daily based on response) 2

Neonates

• Premature newborns (26-29 weeks gestation): same mg/kg dose as older children but every 72 hours for first 2 weeks of life, then daily 2

Critical Pitfalls and Caveats

Resistance Monitoring

• C. glabrata may develop resistance during therapy; monitor clinical response closely 3, 7
• Do not use fluconazole for empirical therapy in patients who received azole prophylaxis 1

Catheter Management

• Removal of indwelling catheters is essential; continuing catheters during treatment significantly reduces cure rates 3, 7

Loading Dose Principle

• A loading dose of twice the daily dose on day 1 achieves near steady-state concentrations by day 2 2
• This is critical for serious infections requiring rapid therapeutic levels 2

Inappropriate Use

• Do not use fluconazole prophylaxis routinely in immunocompetent patients taking antibiotics—this promotes resistance without proven benefit 7
• Candida in respiratory secretions does not indicate pneumonia and should not trigger antifungal therapy 1