What is the recommended dose of Fluconazole (Flucanazole) for fungal infections?

Fluconazole Dosing for Fungal Infections

For systemic candidiasis, initiate fluconazole with a loading dose of 800 mg (12 mg/kg) on day 1, followed by 400 mg (6 mg/kg) daily maintenance dosing, continuing for 2 weeks after the first negative blood culture and resolution of symptoms. 1, 2

Systemic Candida Infections (Candidemia)

Loading and Maintenance Dosing:

• Loading dose: 800 mg (12 mg/kg) on day 1 1, 2
• Maintenance: 400 mg (6 mg/kg) daily 3, 1, 2, 4
• Duration: 2 weeks after first negative blood culture and symptom resolution 1, 2
• In neutropenic patients, continue for 2 weeks after neutropenia resolution (neutrophil count >1000 cells/mm³) 2

Critical Species Considerations:

• Fluconazole has NO activity against Candida krusei and variable activity against C. glabrata—confirm susceptibility before use 1, 2
• For C. parapsilosis, fluconazole is appropriate; if echinocandin used initially, consider switching to fluconazole 2
• For C. glabrata, use echinocandin or amphotericin B initially; only switch to fluconazole if susceptibility confirmed and patient clinically improved 2
• For C. krusei, use echinocandin, amphotericin B, or voriconazole—fluconazole is NOT effective 2

Oropharyngeal Candidiasis

• Loading dose: 200 mg on day 1 1, 5, 4
• Maintenance: 100 mg once daily for 7-14 days 1, 5, 4
• Topical agents are preferred for mild disease 5
• Relapse rate is high (40%) in immunocompromised patients—consider maintenance therapy 6

Esophageal Candidiasis

• Loading dose: 200 mg on day 1 5, 4
• Maintenance: 100 mg once daily 5, 4
• Doses up to 400 mg daily may be used based on clinical response 5, 4
• Minimum treatment duration: 14-21 days and at least 2 weeks after symptom resolution 1, 5, 4

Urinary Tract Infections

Symptomatic Cystitis:

• 200 mg (3 mg/kg) daily for 14 days 3, 1, 2, 5

Pyelonephritis:

• 200-400 mg (3-6 mg/kg) daily for 14 days 3, 1, 2, 5
• If disseminated candidiasis is suspected, treat as candidemia 3

Asymptomatic Candiduria:

• Therapy not usually indicated unless high-risk patients (neonates, neutropenic adults) or undergoing urologic procedures 3
• For procedures: 200-400 mg (3-6 mg/kg) daily for several days before and after 3

CNS Candidiasis

• 400-800 mg (6-12 mg/kg) daily 3, 1, 2
• Liposomal amphotericin B with or without flucytosine is preferred; fluconazole is for patients unable to tolerate amphotericin B 3, 1
• Continue until all signs, symptoms, CSF abnormalities, and radiologic findings resolve 2

Chronic Disseminated Candidiasis

• 400 mg (6 mg/kg) daily for stable patients 3, 1
• Transition from amphotericin B to fluconazole after several weeks in stable patients 3
• Duration: Until lesions resolve (typically 3-6 months), continuing through periods of immunosuppression 3, 1

Vulvovaginal Candidiasis

• Single dose: 150 mg orally 3, 4
• For recurrent vulvovaginal candidiasis: 150 mg weekly for 6 months after initial control 3

Candida Osteoarticular Infections

Osteomyelitis:

• 400 mg (6 mg/kg) daily for 6-12 months 3
• Surgical debridement frequently necessary 3

Septic Arthritis:

• 400 mg (6 mg/kg) daily for at least 6 weeks 3
• Surgical debridement recommended for all cases 3
• For infected prosthetic joints, removal recommended 3

Pediatric Dosing Conversion

• 3 mg/kg ≈ 100 mg adult dose 1, 2, 5
• 6 mg/kg ≈ 200 mg adult dose 2
• 12 mg/kg ≈ 400 mg adult dose 2
• Some older children may have clearances similar to adults; absolute doses exceeding 600 mg/day are not recommended 4

Prophylaxis in Bone Marrow Transplant

• 400 mg once daily 3, 4
• Start several days before anticipated neutropenia (neutrophils <500 cells/mm³) 3, 4
• Continue for 7 days after neutrophil count rises above 1000 cells/mm³ 3, 4

Critical Pitfalls to Avoid

Inadequate Treatment Duration:

• Inadequate treatment duration leads to relapse—continue until clinical and laboratory parameters indicate resolution 1, 2
• This is particularly problematic in immunocompromised patients 2

Central Venous Catheter Management:

• Central venous catheter removal is strongly recommended for patients with candidemia 1, 5

Resistance Development:

• Resistance is particularly problematic in patients with recurrent or chronic infections 2, 5
• For fluconazole-resistant species, use alternative antifungals (echinocandins, amphotericin B, voriconazole) 1, 5

Prior Azole Exposure:

• Do not use azoles in neutropenic patients with prior azole prophylaxis 3
• For patients with moderately severe to severe illness and/or recent azole exposure, an echinocandin is preferred 3