Recommended Dosing of Diflucan (Fluconazole) for Fungal Infections
The recommended dosage of fluconazole varies based on the type and severity of fungal infection, with typical adult doses ranging from 100-400 mg daily depending on the infection site and severity.
General Dosing Principles
- Oral absorption is rapid and almost complete, making oral and intravenous doses equivalent 1
- A loading dose of twice the daily dose is generally recommended on the first day of therapy to achieve steady-state plasma concentrations more quickly 1
- Treatment duration should continue until clinical parameters or laboratory tests indicate the active fungal infection has resolved 1
Specific Dosing Recommendations by Infection Type
Oropharyngeal Candidiasis
- For mild disease: Fluconazole is not first-line (topical agents preferred) 2
- For moderate to severe disease: 200 mg on first day, followed by 100 mg once daily for 7-14 days 1, 2
- Clinical resolution typically occurs within several days, but treatment should continue for at least 2 weeks to prevent relapse 1
Esophageal Candidiasis
- Standard dosing: 200 mg on first day, followed by 100 mg once daily for 14-21 days 1, 2
- For severe cases: Doses up to 400 mg daily may be used based on clinical response 1, 2
- Minimum treatment duration is 3 weeks and at least 2 weeks following symptom resolution 1
- For fluconazole-refractory disease, alternative antifungals are recommended 2
Vaginal Candidiasis
- For uncomplicated cases: 150 mg as a single oral dose 1, 3
- Clinical efficacy rates of 92-99% have been reported with this single-dose regimen 4
Systemic Candida Infections (Candidemia)
- Standard dosing: 400 mg (6 mg/kg) daily 2, 1
- Optimal duration is not firmly established but generally continues for 2 weeks after blood cultures become negative and symptoms resolve 2
- For fluconazole-resistant species, alternative antifungals are recommended 2
Urinary Tract Infections
- For symptomatic cystitis: 200 mg (3 mg/kg) daily for 2 weeks 2
- For pyelonephritis: 200-400 mg (3-6 mg/kg) daily for 2 weeks 2
Cryptococcal Meningitis
- Initial treatment: 400 mg on first day, followed by 200-400 mg once daily 1
- Treatment should continue for 10-12 weeks after cerebrospinal fluid becomes culture negative 1
- For suppression/maintenance in AIDS patients: 200 mg once daily 1
Prophylaxis in Bone Marrow Transplantation
- 400 mg once daily, starting several days before anticipated onset of neutropenia and continuing for 7 days after neutrophil count rises above 1000 cells/mm³ 1
Special Populations
Pediatric Dosing
- 3 mg/kg ≈ 100 mg in adults
- 6 mg/kg ≈ 200 mg in adults
- 12 mg/kg ≈ 400 mg in adults (not to exceed 600 mg/day) 1
Renal Impairment
- Dose adjustment required for patients with impaired renal function 1
- For patients on regular hemodialysis, administer full dose after each dialysis session 1
Common Pitfalls and Caveats
- Inadequate treatment duration may lead to recurrence of infection 1
- Fluconazole resistance can develop, particularly in patients with recurrent or chronic infections 2
- For fluconazole-resistant Candida species (e.g., C. glabrata, C. krusei), alternative antifungal agents should be used 2
- Growth of Candida from respiratory secretions usually indicates colonization rather than infection and rarely requires antifungal therapy 2
- Central venous catheter removal is strongly recommended in cases of candidemia 2
Remember that treatment duration should be guided by clinical and microbiological response, with longer courses typically needed for invasive infections 2, 1.