Fluconazole (Diflucan) Dosage and Treatment Regimens for Fungal Infections
Fluconazole dosing should be tailored to the specific fungal infection type, with dosages ranging from 100-400 mg daily for most systemic infections, with treatment duration determined by clinical response and infection clearance.1
General Dosing Principles
- Oral absorption of fluconazole is rapid and almost complete, making oral and intravenous doses equivalent 2
- 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 2
- Treatment should continue until clinical parameters and laboratory tests indicate the active fungal infection has resolved 2
Specific Dosing Regimens by Infection Type
Oropharyngeal Candidiasis
- 200 mg on first day, followed by 100 mg once daily 2
- Continue treatment for at least 2 weeks to prevent relapse 2
- For moderate to severe disease, 100-200 mg daily for 7-14 days 1
Esophageal Candidiasis
- 200 mg on first day, followed by 100 mg once daily 2
- Doses up to 400 mg/day may be used based on clinical response 2
- Minimum treatment duration of 3 weeks and at least 2 weeks following symptom resolution 2
Vaginal Candidiasis
- Uncomplicated: 150 mg as a single oral dose 2, 3
- Complicated/severe: Two 150 mg doses given 3 days apart 4
- Recurrent: 150 mg weekly for 6 months after initial control of the infection 1
Systemic Candida Infections (Candidemia, Disseminated Candidiasis)
- 400 mg (6 mg/kg) daily, though optimal dosage not fully established 2
- Treatment should continue for 14 days after documented clearance from bloodstream and resolution of symptoms 1
- Central venous catheter removal is strongly recommended when possible 1
Urinary Tract Candida Infections
- Asymptomatic candiduria: Treatment not recommended unless patient is at high risk for dissemination 1
- 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
- Patients undergoing urologic procedures: 400 mg (6 mg/kg) daily for several days before and after the procedure 1
Cryptococcal Meningitis
- Initial treatment: 400 mg on first day, followed by 200 mg once daily 2
- Dosage may be increased to 400 mg daily based on clinical response 2
- Treatment duration: 10-12 weeks after cerebrospinal fluid becomes culture negative 2
- Suppression therapy for AIDS patients: 200 mg once daily 2
Prophylaxis in Bone Marrow Transplant Patients
- 400 mg once daily 2
- Begin several days before anticipated onset of neutropenia and continue for 7 days after neutrophil count exceeds 1000 cells/mm³ 2
Special Considerations
Fluconazole-Resistant Infections
- For fluconazole-resistant Candida glabrata: Consider amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days with or without flucytosine 1
- For Candida krusei: Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
Pediatric Dosing
- Dosing should be adjusted based on weight to provide equivalent exposure to adult dosing 2
- Absolute doses exceeding 600 mg/day are not recommended 2
Common Pitfalls and Caveats
- Inadequate treatment duration may lead to recurrence of active infection 2
- Patients with AIDS and cryptococcal meningitis or recurrent oropharyngeal candidiasis usually require maintenance therapy to prevent relapse 2
- Removal of infected central nervous system devices, including ventriculostomy drains and shunts, is strongly recommended when possible 1
- Fluconazole has limited efficacy against Aspergillus species at conventional dosages 5
- For candidal urinary tract infections, elimination of predisposing factors such as indwelling bladder catheters is recommended whenever feasible 1