Fluconazole (Diflucan) Dosing Regimens for Fungal Infections
Fluconazole dosing varies by infection type, with specific regimens ranging from a single 150 mg dose for vaginal candidiasis to 400 mg daily for severe systemic infections like cryptococcal meningitis. The dosing recommendations are based on established clinical guidelines from the Infectious Diseases Society of America.
Mucocutaneous Candidiasis
Oropharyngeal Candidiasis
- Loading dose: 200 mg on first day
- Maintenance: 100 mg once daily
- Duration: At least 2 weeks to prevent relapse 1, 2
Esophageal Candidiasis
- Loading dose: 200 mg on first day
- Maintenance: 100 mg once daily (up to 400 mg/day for severe cases)
- Duration: Minimum 3 weeks and at least 2 weeks after symptom resolution 1, 2
Vulvovaginal Candidiasis
- Uncomplicated: 150 mg as a single oral dose 1, 2, 3
- Recurrent: 150 mg weekly for 6 months after initial control 1
Systemic Candidiasis
Candidemia/Invasive Candidiasis
- Dose: 400 mg (6 mg/kg) daily
- Duration: 2 weeks after documented clearance of Candida from bloodstream and resolution of symptoms 1, 2
Urinary Tract Infections
- Asymptomatic cystitis: Generally not treated unless high-risk patient
- Symptomatic cystitis: 200 mg (3 mg/kg) daily for 2 weeks 1
- Pyelonephritis: 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
Chronic Disseminated Candidiasis
- Dose: 400 mg (6 mg/kg) daily
- Duration: Until lesions resolve (usually months) 1
Cryptococcal Infections
Cryptococcal Meningitis
- Loading dose: 400 mg on first day
- Maintenance: 200-400 mg once daily
- Duration: 10-12 weeks after CSF becomes culture negative 2
- Suppression for AIDS patients: 200 mg once daily 2
Prophylaxis
Bone Marrow Transplantation
- Dose: 400 mg once daily
- Timing: Start before anticipated onset of neutropenia and continue for 7 days after neutrophil count rises above 1000 cells/mm³ 2
Pediatric Dosing
- 3 mg/kg equivalent to adult 100 mg
- 6 mg/kg equivalent to adult 200 mg
- 12 mg/kg equivalent to adult 400 mg
- Maximum recommended dose: 600 mg/day 2
Clinical Considerations
Dosing Adjustments
- Renal impairment: Reduce dose based on creatinine clearance
- Hepatic impairment: Monitor liver function tests but dose adjustment usually not required
Administration
- Oral absorption is rapid and nearly complete (>90%)
- Can be taken with or without food
- Same daily dose for oral and intravenous administration 2
Treatment Duration
- Continue until clinical parameters or laboratory tests indicate resolution of active infection
- Inadequate treatment duration may lead to recurrence 2
Monitoring
- Monitor liver function tests for extended therapy
- Follow-up cultures to confirm eradication in invasive infections
Common Pitfalls
- Underestimating treatment duration for deep-seated infections
- Failure to use loading doses when indicated
- Not adjusting doses for renal impairment
- Inadequate follow-up to confirm infection clearance
Fluconazole remains a cornerstone antifungal therapy due to its excellent tissue penetration, including into the cerebrospinal fluid, and its favorable safety profile compared to amphotericin B formulations 4.