Fluconazole Dosage in HIV

Adults

For cryptococcal meningitis, fluconazole is not as effective as amphotericin B + flucytosine for induction. It is the drug of choice for consolidation and maintenance therapy. High-dose fluconazole (1200 mg/day) is used in some resource-limited settings as an alternative induction agent.

• The Washington Manual of Medical Therapeutics
• The Harriet Lane Handbook (Harriet Lane, 23rd ed.)

Children (>=1 month, IV/PO)

• The Harriet Lane Handbook, 23rd ed.

Neonates (Thrush)

• 3-6 mg/kg/dose; dosing interval varies by postconceptional age (24-48 hours)

Important Notes

• Renal impairment: Dose reduction required in severe renal impairment (fluconazole is renally cleared).
• Hepatic impairment: Use with caution; monitor closely.
• Drug interactions (relevant in HIV): Fluconazole inhibits CYP2C9/10 and CYP3A3/4. It increases levels of AZT (zidovudine), cyclosporine, tacrolimus, warfarin, oral hypoglycemics, phenytoin, rifabutin, and statins. Rifampin increases fluconazole metabolism (may reduce fluconazole efficacy).
• QT prolongation: Avoid combination with other QT-prolonging drugs (e.g., erythromycin, certain antiretrovirals).
• Resistance: Increasing fluconazole resistance in Candida species is a concern, especially in HIV patients with prior azole exposure. Candida krusei is intrinsically resistant; C. glabrata has reduced susceptibility.
• Fluconazole has no activity against Aspergillus or other mold infections.

Key Principle for Cryptococcal Meningitis in HIV

1. Induction (2 weeks): Amphotericin B (liposomal preferred) + flucytosine
2. Consolidation (8 weeks): Fluconazole 400-800 mg/day
3. Maintenance/Prophylaxis (ongoing): Fluconazole 200 mg/day - can be discontinued after CD4 >100-200 cells/uL is sustained on ART

• Goldman-Cecil Medicine, International Edition
• Washington Manual of Medical Therapeutics

Recent HIV Antifungal Guidelines & Protocols

1. Candidiasis (Updated Sept 2024 - NIH OI Guidelines)

Oropharyngeal Candidiasis (Thrush)

• Preferred: Fluconazole 100 mg PO daily x 7-14 days (strong, high evidence)
• Alternative: Clotrimazole troches 10 mg 5x/day, or nystatin suspension - for mild, uncomplicated cases
• Refractory (fluconazole-resistant): Itraconazole oral solution 200 mg/day, posaconazole 400 mg BD, or an echinocandin (micafungin, caspofungin)

Esophageal Candidiasis

• Preferred: Fluconazole 200-400 mg PO/IV daily x 14-21 days (strong, high evidence - IDSA)
• Refractory: Echinocandin (caspofungin 70 mg load then 50 mg/day, micafungin 150 mg/day, anidulafungin 200 mg load then 100 mg/day) x 14-21 days; OR voriconazole 200 mg BD
• Chronic suppression (frequent recurrences): Fluconazole 100 mg 3x/week (strong, high evidence - IDSA)

New in 2024 (NIH OI Guidelines)

• Ibrexafungerp added as an option for vulvovaginal candidiasis (VVC) and recurrent VVC - FDA approved
• Oteseconazole added for recurrent VVC
• ART strongly recommended to reduce all recurrent Candida infections (strong, high evidence)

2. Cryptococcal Meningitis - Full Protocol

Screening (WHO 2022 / NIH Guidelines)

• Screen all HIV+ patients with CD4 <100 cells/mm³ for cryptococcal antigen (CrAg) before ART initiation
• Consider screening at CD4 <200 cells/mm³ (conditional recommendation)
• CrAg+ without symptoms: Pre-emptive fluconazole 800-1200 mg/day x 2 weeks, then consolidation + maintenance

Induction (2 weeks) - Preferred

• Fluconazole 1200 mg/day + flucytosine 25 mg/kg QID x 1 week, then fluconazole 1200 mg/day x 1 week (BI)
• If flucytosine unavailable: Fluconazole 1200 mg/day x 2 weeks (BIII)

Consolidation (8 weeks)

• Preferred: Fluconazole 800 mg/day (WHO) or 400-800 mg/day (NIH) PO x 8 weeks
• EACS: 400 mg/day after single 800 mg loading dose day 1
• If fluconazole MIC ≥16 µg/mL: Increase to 1200 mg/day + consider weekly AmB (BIII)

Maintenance / Secondary Prophylaxis (≥1 year total)

• Preferred: Fluconazole 200 mg/day PO (AI - strong, high evidence - WHO)
• Alternative: Itraconazole 200 mg BD (if fluconazole unavailable/intolerated)

Stopping Maintenance (all 3 criteria required - BII):

1. ≥1 year from start of antifungal therapy
2. Asymptomatic from cryptococcosis
3. CD4 ≥100 cells/mm³ AND suppressed HIV viral load on ART

ART Timing in Cryptococcal Meningitis

• Defer ART 4-6 weeks after starting antifungals for CNS cryptococcosis (AI) - early ART increases mortality due to IRIS

3. Other Fungal Infections in HIV

Pneumocystis jirovecii Pneumonia (PCP) - Not a true antifungal but relevant

• Primary prophylaxis: TMP-SMX (preferred); alternative - dapsone, atovaquone
• Threshold: CD4 <200 cells/mm³

Histoplasmosis

• Mild-moderate: Itraconazole 200 mg TID x 3 days, then 200-400 mg/day
• Severe/disseminated: Liposomal AmB 3 mg/kg/day x 1-2 weeks, then itraconazole
• Maintenance: Itraconazole 200 mg/day until CD4 >150 cells/mm³ x ≥1 year

Coccidioidomycosis

• Fluconazole 400 mg/day or itraconazole 200 mg BD
• Meningeal disease: Fluconazole 400-800 mg/day (lifelong in HIV)

4. Evidence Rankings for Oral Candidiasis Treatments (2025 Network Meta-Analysis)

5. Key 2024-2025 Guideline Changes to Know