Fluconazole (Diflucan) Dosing for Fungal Infections

Vaginal Candidiasis

A single oral dose of 150 mg fluconazole is the recommended treatment for uncomplicated vaginal candidiasis. 1

This single-dose regimen achieves clinical cure rates of 88% at long-term follow-up (27-62 days) with excellent tolerability 2
No loading dose or extended therapy is required for this indication 1

For moderate to severe oropharyngeal candidiasis, fluconazole 100-200 mg daily for 7-14 days is recommended. 3

The FDA-approved regimen is 200 mg on day 1, followed by 100 mg once daily 1
Topical agents (clotrimazole troches or miconazole buccal tablets) are preferred first-line for mild disease 3
Treatment should continue for at least 2 weeks to decrease relapse risk 1
For fluconazole-refractory disease, switch to itraconazole solution 200 mg daily or posaconazole suspension 400 mg twice daily for 3 days then 400 mg daily 3

Fluconazole 200-400 mg daily for 14-21 days is the standard treatment for esophageal candidiasis. 3

Start with 200 mg on day 1, followed by 100 mg once daily 1
Doses up to 400 mg daily may be used based on clinical response and severity 3, 1
Continue treatment for a minimum of 3 weeks and at least 2 weeks after symptom resolution 1
For patients unable to tolerate oral therapy, use IV fluconazole 400 mg daily or an echinocandin 3

For candidemia and disseminated candidiasis, fluconazole 400 mg (6 mg/kg) daily is recommended. 4

A loading dose of 800 mg (12 mg/kg) on day 1 is recommended to achieve steady-state concentrations rapidly 3
Continue treatment for at least 2 weeks after blood cultures clear and symptoms resolve 4
Central venous catheter removal is strongly recommended 4
This regimen is appropriate for step-down therapy after initial echinocandin treatment in stable patients with susceptible isolates 3

For symptomatic Candida cystitis, fluconazole 200 mg (3 mg/kg) daily for 2 weeks is recommended. 4

For Candida pyelonephritis, increase to 200-400 mg (3-6 mg/kg) daily for 2 weeks 3, 4
Elimination of urinary tract obstruction is strongly recommended 3
Consider removal or replacement of nephrostomy tubes or stents if present 3

For acute cryptococcal meningitis, fluconazole 400 mg on day 1, followed by 200-400 mg once daily is recommended. 1

Treatment duration is 10-12 weeks after cerebrospinal fluid becomes culture-negative 1
For suppression of relapse in AIDS patients, use fluconazole 200 mg once daily as maintenance therapy 1

Fluconazole 400 mg once daily is recommended for prevention of candidiasis in bone marrow transplant patients. 1

Start several days before anticipated onset of severe neutropenia (< 500 cells/mm³) 1
Continue for 7 days after neutrophil count rises above 1000 cells/mm³ 1

Pediatric dosing equivalents are: 3 mg/kg ≈ 100 mg adult dose; 6 mg/kg ≈ 200 mg adult dose; 12 mg/kg ≈ 400 mg adult dose. 1

Oral and IV dosing are equivalent due to >90% bioavailability 1, 5
Loading doses of twice the daily dose on day 1 achieve near steady-state by day 2 1
Half-life is approximately 30-37 hours, supporting once-daily dosing 5
Food, hypochlorhydria, and gastrointestinal resection do not affect absorption 5

Fluconazole has no activity against Candida krusei (intrinsically resistant) and variable activity against C. glabrata 3
For C. krusei infections, use amphotericin B or an echinocandin instead 3
Candida isolated from respiratory secretions usually represents colonization, not infection, and rarely requires treatment 3, 4
Inadequate treatment duration may lead to recurrence of active infection 1
Chronic suppressive therapy (fluconazole 100 mg three times weekly) is usually unnecessary except in patients with recurrent infections 3