Fluconazole Dosing for Fungal Infections
For invasive candidiasis including candidemia, administer a loading dose of 800 mg (12 mg/kg) on day 1, followed by 400 mg (6 mg/kg) daily, continuing for 2 weeks after documented clearance of Candida from the bloodstream and resolution of symptoms. 1, 2
Candidemia and Invasive Candidiasis
Loading and Maintenance Dosing:
- Loading dose: 800 mg (12 mg/kg) on day 1 1, 2
- Maintenance: 400 mg (6 mg/kg) daily 1, 2
- Duration: 2 weeks after documented clearance from bloodstream and symptom resolution 1
Critical Patient Selection Considerations:
- Fluconazole is appropriate for less critically ill patients without recent azole exposure 1
- Echinocandins are preferred for critically ill patients, those with recent azole exposure, or suspected C. glabrata/C. krusei infections 1
- For C. parapsilosis infections specifically, fluconazole is preferred over echinocandins 1
- Fluconazole has NO activity against C. krusei and variable activity against C. glabrata 3
Mucocutaneous Candidiasis
Oropharyngeal Candidiasis:
- Initial dose: 200 mg on day 1 4, 2
- Maintenance: 100 mg daily for 7-14 days 4, 3, 2
- Treat for minimum 2 weeks to decrease relapse likelihood 2
Esophageal Candidiasis:
- Initial dose: 200 mg on day 1 4, 2
- Maintenance: 100-400 mg daily for 14-21 days 4, 3, 2
- Continue for minimum 3 weeks and at least 2 weeks following symptom resolution 2
Vaginal Candidiasis:
- Single dose: 150 mg orally 2
Urinary Tract Candidiasis
Symptomatic Cystitis:
Pyelonephritis:
- 200-400 mg (3-6 mg/kg) daily for 14 days 1, 3
- If disseminated candidiasis is suspected, treat as candidemia 1
CNS Candidiasis
- 400-800 mg (6-12 mg/kg) daily for patients unable to tolerate amphotericin B 1
- Remove intraventricular devices 1
- Continue until all signs, symptoms, CSF abnormalities, and radiologic findings resolve 1
Cryptococcal Meningitis
Acute Treatment:
- 400 mg on day 1, followed by 200-400 mg daily 2
- Duration: 10-12 weeks after CSF becomes culture negative 2
Suppressive Therapy (AIDS patients):
- 200 mg daily to prevent relapse 2
Chronic Disseminated Candidiasis
- 400 mg (6 mg/kg) daily 1
- Continue until lesions resolve on imaging, typically several months 1
- Premature discontinuation leads to relapse 1
Empirical Therapy in ICU Patients
For suspected invasive candidiasis in nonneutropenic ICU patients:
- Loading dose: 800 mg (12 mg/kg) 1
- Maintenance: 400 mg (6 mg/kg) daily 1
- This is acceptable for patients without recent azole exposure and not colonized with azole-resistant species 1
- Echinocandins are preferred for empirical therapy in most ICU patients 1
Pediatric Dosing
Dose equivalency for pediatric patients: 2
- 3 mg/kg pediatric dose ≈ 100 mg adult dose
- 6 mg/kg pediatric dose ≈ 200 mg adult dose
- 12 mg/kg pediatric dose ≈ 400 mg adult dose
- Maximum dose: 600 mg/day 2
Pharmacokinetic Considerations
Key Properties:
- Bioavailability exceeds 90% for oral formulations 5, 6
- Half-life: 31-37 hours, allowing once-daily dosing 5, 6
- Loading dose recommended (double the maintenance dose) to achieve steady-state by day 2 2, 6
- Low protein binding (11-12%), extensive tissue distribution 5, 6
- Primarily renally eliminated (60% unchanged in urine) 5, 6
Critical Pitfalls to Avoid
Species-Specific Resistance:
- Never use fluconazole empirically if C. krusei is suspected (intrinsic resistance) 3
- Exercise caution with C. glabrata (variable susceptibility) 1, 3
Respiratory Colonization:
- Candida isolated from respiratory secretions usually represents colonization, not infection 3
- Rarely requires treatment unless histopathologic evidence confirms invasive disease 1
Renal Adjustment:
- Dosage adjustment required in renal insufficiency based on creatinine clearance 5, 6
- In hemodialysis: 100-200 mg after each dialysis session 6
Drug Interactions: