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

Fluconazole Dosing for Fungal Infections

For most systemic Candida infections (candidemia), initiate fluconazole with a loading dose of 800 mg (12 mg/kg) on day 1, followed by 400 mg (6 mg/kg) daily maintenance dosing, continuing for 2 weeks after the first negative blood culture and resolution of symptoms. 1, 2, 3

Systemic Candida Infections (Candidemia and Invasive Candidiasis)

• Loading dose: 800 mg (12 mg/kg) on day 1, then 400 mg (6 mg/kg) daily for candidemia and disseminated candidiasis 1, 2, 4
• Continue treatment for 2 weeks after documented clearance from bloodstream and symptom resolution 1, 2
• For neutropenic patients, extend therapy for 2 weeks after neutropenia resolves (neutrophil count >1000 cells/mm³) 1
• Central venous catheter removal is strongly recommended for all patients with candidemia 1, 4

Critical Species-Specific Considerations:

• Fluconazole has NO activity against Candida krusei and variable activity against C. glabrata—confirm susceptibility before use 1, 2, 4
• For C. parapsilosis, fluconazole is appropriate; if echinocandin used initially, consider switching to fluconazole 5
• For C. glabrata, only use fluconazole after confirming susceptibility with negative follow-up cultures 5
• For C. krusei, use echinocandins or amphotericin B instead 5

Oropharyngeal and Esophageal Candidiasis

Oropharyngeal:

• Loading dose: 200 mg on day 1, then 100 mg once daily for 7-14 days 1, 2, 4
• For moderate to severe disease, increase to 100-200 mg daily 2
• Topical agents are preferred first-line for mild disease 2

Esophageal:

• 200-400 mg daily for 14-21 days until clinical improvement 5, 2
• Treat for minimum 3 weeks and at least 2 weeks following symptom resolution 2, 3
• Doses up to 400 mg/day may be used based on clinical response 3

Urinary Tract Infections

Symptomatic Cystitis:

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

Pyelonephritis:

• 200-400 mg (3-6 mg/kg) daily for 14 days 5, 1, 2, 4
• For patients with suspected disseminated candidiasis, treat as candidemia 5

Asymptomatic Candiduria:

• Therapy not usually needed 5
• For high-risk surgical patients, neonates, or neutropenic patients, treat as disseminated candidiasis 5

CNS Candidiasis

• 400-800 mg (6-12 mg/kg) daily for patients unable to tolerate amphotericin B 5, 1, 2, 4
• Amphotericin B with or without flucytosine is preferred; fluconazole is reserved for intolerant patients 5, 1
• Remove intraventricular devices 5
• Continue until all signs, symptoms, CSF abnormalities, and radiologic findings resolve 5

Chronic Disseminated Candidiasis

• 400 mg (6 mg/kg) daily for stable patients 1, 2, 4
• Continue until lesions resolve on imaging, typically 3-6 months 5, 4
• Transition from amphotericin B to fluconazole after several weeks in stable patients 5, 4

Vulvovaginal Candidiasis

• Single dose of 150 mg orally 1, 3, 6
• Clinical cure rate of 88% at long-term follow-up (27-62 days) 6

Candida Endophthalmitis

• Fluconazole is an alternative option (specific dose not standardized in guidelines) 5
• Duration at least 4-6 weeks, determined by repeated examinations 5
• Surgical intervention required for severe endophthalmitis or vitreitis 5

Candida Osteoarticular Infections

• 400 mg (6 mg/kg) daily for 6-12 months for osteomyelitis 1
• Surgical debridement frequently necessary 1

Cryptococcal Meningitis

Acute Treatment:

• 400 mg on day 1, then 200 mg once daily 3
• May increase to 400 mg once daily based on clinical response 3
• Treat for 10-12 weeks after CSF becomes culture negative 3

Maintenance/Suppression in AIDS:

• 200 mg once daily to prevent relapse 3

Prophylaxis in Bone Marrow Transplant

• 400 mg once daily 1, 3
• Start several days before anticipated neutropenia onset 3
• Continue for 7 days after neutrophil count rises above 1000 cells/mm³ 3

Pediatric Dosing Conversion

• 3 mg/kg ≈ 100 mg adult dose 1, 4
• 6 mg/kg ≈ 200 mg adult dose 1, 4
• 12 mg/kg ≈ 400 mg adult dose 1, 4
• Some older children may have clearances similar to adults; absolute doses exceeding 600 mg/day are not recommended 3

Neonatal Candidiasis

• Amphotericin B 1.0 mg/kg/day OR fluconazole 12 mg/kg/day OR echinocandin 5
• Lumbar puncture and ophthalmoscopic examination recommended 5
• For candidemia without persistent fungemia or metastatic complications, treat for 3 weeks 5

Critical Pitfalls to Avoid

• Inadequate treatment duration leads to relapse—continue until clinical and laboratory parameters indicate resolution 1, 4
• Relapse rates are high (40%) in immunocompromised patients, particularly those with AIDS 7, 8
• Candida isolated from respiratory secretions usually represents colonization, not infection—rarely requires treatment 2
• For fluconazole-resistant species, use alternative antifungals (echinocandins, amphotericin B, voriconazole) 1, 4
• Maximum daily dose of 1600 mg recommended to avoid neurological toxicity 7
• Hypochlorhydria, food intake, and gastrointestinal resection do not affect fluconazole absorption 7