What is the recommended dose of fluconazole (antifungal medication) for various fungal infections?

Fluconazole Dosing for Fungal Infections

For systemic candidiasis, use a loading dose of 800 mg (12 mg/kg) on day 1, followed by 400 mg (6 mg/kg) daily maintenance dosing. 1, 2, 3

Oropharyngeal Candidiasis

• Loading dose: 200 mg on day 1 2, 4, 3
• Maintenance: 100 mg once daily for 7-14 days 2, 5, 4, 3
• For moderate to severe disease, doses up to 200 mg daily may be used 5, 4
• Continue treatment for at least 2 weeks to decrease relapse likelihood 3
• Important caveat: Relapse rates approach 40% in immunocompromised patients (particularly AIDS patients), who typically require long-term maintenance therapy 6, 7

Esophageal Candidiasis

• Loading dose: 200 mg on day 1 5, 4, 3
• Maintenance: 100 mg once daily 5, 3
• Doses up to 400 mg daily may be used based on clinical response 5, 3
• Duration: Minimum 14-21 days and at least 2 weeks following symptom resolution 2, 5, 3

Systemic Candida Infections (Candidemia, Disseminated Candidiasis)

• Loading dose: 800 mg (12 mg/kg) on day 1 1, 2
• Maintenance: 400 mg (6 mg/kg) daily 1, 2, 5, 3
• Duration: Continue for 2 weeks after first negative blood culture and resolution of symptoms 1, 4
• For candidemia without persistent fungemia or metastatic complications, treat for 2-3 weeks after neutropenia resolution and negative cultures 1
• Critical action: Central venous catheter removal is strongly recommended 2, 4

CNS Candidiasis

• Dose: 400-800 mg (6-12 mg/kg) daily for patients unable to tolerate amphotericin B 1, 2
• Continue until all signs, symptoms, CSF abnormalities, and radiologic findings resolve 1
• Removal of intraventricular devices is recommended 1

Urinary Tract Infections

Symptomatic Cystitis

• Dose: 200 mg (3 mg/kg) daily for 14 days 1, 2, 5, 4

Pyelonephritis

• Dose: 200-400 mg (3-6 mg/kg) daily for 14 days 1, 2, 5, 4
• If disseminated candidiasis is suspected, treat as candidemia 1

Asymptomatic Cystitis

• Therapy usually not needed 1
• Exception: Treat high-risk surgical patients, neonates, or neutropenic patients as disseminated candidiasis 1

Chronic Disseminated Candidiasis

• Dose: 400 mg (6 mg/kg) daily 2
• Duration: Continue until lesions resolve, typically 3-6 months 1, 2
• Can be used as step-down therapy in stable patients 1

Vaginal Candidiasis

• Single dose: 150 mg as a single oral dose 3, 8
• This provides approximately 75-84% clinical cure rates 6, 8

Cryptococcal Meningitis

• Treatment: 400 mg on day 1, followed by 200 mg once daily 3
• Doses up to 400 mg daily may be used based on response 3
• Duration: 10-12 weeks after CSF becomes culture negative 3
• Maintenance (AIDS patients): 200 mg once daily to prevent relapse 3

Pediatric Dosing Conversion

• 3 mg/kg ≈ 100 mg adult dose 2, 4
• 6 mg/kg ≈ 200 mg adult dose 4
• 12 mg/kg ≈ 400 mg adult dose 1
• Absolute doses exceeding 600 mg/day are not recommended in children 3

Critical Species-Specific Considerations

Fluconazole has NO activity against Candida krusei and variable activity against C. glabrata—confirm susceptibility before use. 2, 5

• C. parapsilosis: Fluconazole is appropriate; if echinocandin used initially, consider switching to fluconazole 1
• C. glabrata: Use echinocandin or amphotericin B initially; only switch to fluconazole if susceptibility confirmed and patient clinically improved 1
• C. krusei: Use echinocandin, amphotericin B, or voriconazole—fluconazole is NOT effective 1

Common Pitfalls to Avoid

• Respiratory secretions: Candida isolated from respiratory tract usually represents colonization, not infection—treatment rarely required 5, 4
• Inadequate treatment duration: Leads to relapse; continue until clinical and laboratory parameters indicate resolution 2
• Resistance development: Particularly problematic in patients with recurrent or chronic infections 4
• Neutropenic patients: Require longer treatment duration (2 weeks after neutropenia resolution) 1