What is the typical dose of Diflucan (fluconazole) for an adult?

Typical Fluconazole (Diflucan) Dosing for Adults

For invasive candidiasis, fluconazole should be administered with a loading dose of 800 mg (12 mg/kg) on day one, followed by 400 mg (6 mg/kg) daily thereafter. 1

Dosing by Indication

Vaginal Candidiasis

• Single dose of 150 mg orally is the standard treatment for uncomplicated cases 2, 3, 4
• Clinical cure rates exceed 90% with this single-dose regimen 2
• For recurrent vulvovaginal candidiasis (≥4 episodes/year), use 150 mg weekly for 6 months as maintenance therapy after initial control 2

Oropharyngeal Candidiasis

• 200 mg loading dose on day 1, then 100 mg daily for at least 2 weeks 1, 3
• Alternative dosing: 100-200 mg daily for 7-14 days for moderate-severe disease 2, 5
• Treatment should continue for at least 2 weeks to decrease relapse likelihood 3

Esophageal Candidiasis

• 200 mg loading dose on day 1, then 100 mg daily 3
• Doses up to 400 mg daily may be used based on clinical response 1, 3
• Minimum treatment duration is 3 weeks and at least 2 weeks after symptom resolution 3

Invasive Candidiasis/Candidemia

• 800 mg (12 mg/kg) loading dose on day 1, then 400 mg (6 mg/kg) daily 1
• This loading dose strategy achieves near-steady-state concentrations by day 2 1, 3
• Continue treatment for 2 weeks after documented clearance from bloodstream 1

Urinary Tract Candidiasis

• Asymptomatic candiduria: No treatment needed in immunocompetent patients 1, 2
• Symptomatic cystitis: 200 mg daily for 2 weeks 1, 2
• Pyelonephritis: 200-400 mg daily for 2 weeks 1

Cryptococcal Meningitis

• Acute treatment: 400 mg on day 1, then 200-400 mg daily for 10-12 weeks after CSF becomes culture-negative 3
• Suppressive therapy in AIDS patients: 200 mg daily 3

Prophylaxis in High-Risk Populations

• Bone marrow transplant recipients: 400 mg daily starting several days before anticipated neutropenia, continuing for 7 days after neutrophil count >1000 cells/mm³ 1, 3
• ICU patients (high-risk units with >5% invasive candidiasis incidence): 800 mg loading dose, then 400 mg daily 1
• Neutropenic patients during chemotherapy: 400 mg daily throughout neutropenia period 1, 2
• High-risk solid organ transplant recipients: 200-400 mg daily for 7-14 days postoperatively 1

Critical Dosing Adjustments

Renal Impairment

• Creatinine clearance >50 mL/min: No adjustment needed, use 100% of recommended dose 5
• Creatinine clearance ≤50 mL/min: Reduce to 50% of recommended dose 1, 5
• Hemodialysis patients: Give 100% of recommended dose after each dialysis session 5

Important Pharmacokinetic Considerations

• Oral bioavailability is approximately 90%, making oral and IV dosing equivalent 1
• Absorption is not affected by food, gastric pH, or disease state 1
• Long half-life of 31-37 hours allows once-daily dosing 6, 7
• Achieves CSF concentrations 50-89% of serum levels, making it ideal for CNS infections 1, 7
• Urine concentrations reach 10-20 times serum levels 1

Critical Pitfalls to Avoid

Do not use fluconazole prophylaxis in immunocompetent patients taking antibiotics, even with history of recurrent yeast infections—this promotes resistance without proven benefit 2

Avoid fluconazole for suspected C. glabrata or C. krusei infections as these species have reduced susceptibility; consider echinocandins instead 1

Do not use azole prophylaxis if planning empiric azole therapy—prior azole exposure necessitates switching to an echinocandin for empiric treatment 1

Inadequate treatment duration leads to relapse—continue therapy until clinical parameters and laboratory tests indicate active infection has subsided 3