What are the recommended doses of Fluconazole (fluconazole) for treating different types of fungal infections?

Recommended Doses of Fluconazole for Different Fungal Infections

Fluconazole dosing should follow a structured approach based on infection type, with loading doses of 800 mg (12 mg/kg) followed by 400 mg (6 mg/kg) daily for candidemia and other invasive infections, while less severe infections require lower doses. 1

Systemic Candida Infections

Candidemia and Invasive Candidiasis

• Initial therapy:
  • Loading dose: 800 mg (12 mg/kg)
  • Maintenance dose: 400 mg (6 mg/kg) daily 1
  • Alternative for less critically ill patients with no recent azole exposure: Fluconazole 400 mg (6 mg/kg) daily 1
  • Duration: 2 weeks after documented clearance of Candida from bloodstream and resolution of symptoms 1

Chronic Disseminated Candidiasis

• Fluconazole 400 mg (6 mg/kg) daily 1
• Duration: Until lesions have resolved (typically 3-6 months) 1
• Continue through periods of immunosuppression (e.g., chemotherapy) 1

Mucosal Candidiasis

Oropharyngeal Candidiasis

• Adults:

  • Initial dose: 200 mg on first day
  • Maintenance: 100 mg daily 2
  • Duration: At least 2 weeks to decrease relapse risk 2

• Children:

  • Initial dose: 6 mg/kg on first day
  • Maintenance: 3 mg/kg daily 2
  • Duration: At least 2 weeks 2

Esophageal Candidiasis

• Adults:

  • Initial dose: 200 mg on first day
  • Maintenance: 100 mg daily 2
  • Doses up to 400 mg daily may be used based on response 2
  • Duration: Minimum 3 weeks and at least 2 weeks following symptom resolution 2

• Children:

  • Initial dose: 6 mg/kg on first day
  • Maintenance: 3 mg/kg daily 2
  • Doses up to 12 mg/kg daily may be used based on response 2
  • Duration: Minimum 3 weeks and at least 2 weeks following symptom resolution 2

Urinary Tract Infections

Symptomatic Cystitis

• 200 mg (3 mg/kg) daily for 2 weeks 1, 3

Pyelonephritis

• 200-400 mg (3-6 mg/kg) daily for 2 weeks 1, 3
• For patients with pyelonephritis and suspected disseminated candidiasis, treat as for candidemia 1

Asymptomatic Cystitis

• Treatment not usually indicated unless patients are high-risk (e.g., neonates, neutropenic adults) 1
• For high-risk patients, treat as for disseminated candidiasis 1

Cryptococcal Infections

Cryptococcal Meningitis

• Initial therapy:

  • Initial dose: 400 mg on first day
  • Maintenance: 200-400 mg daily 2
  • Duration: 10-12 weeks after CSF becomes culture negative 2

• Suppression therapy (AIDS patients):

  • 200 mg daily 2

Vaginal Candidiasis

Uncomplicated Vaginitis

• Single oral dose of 150 mg 2, 4
• Clinical cure rates comparable to 7-day topical therapy 4

Recurrent Vulvovaginal Candidiasis

• Initial control: 150 mg single dose
• Maintenance: 150 mg weekly for 6 months 1

Prophylaxis

Bone Marrow Transplantation

• 400 mg daily 2
• Start several days before anticipated onset of neutropenia
• Continue for 7 days after neutrophil count rises above 1000 cells/mm³ 2

Pediatric Dosing

Pediatric dosing equivalents to adult doses:

• 3 mg/kg = 100 mg adult dose
• 6 mg/kg = 200 mg adult dose
• 12 mg/kg = 400 mg adult dose 2
• Maximum recommended dose: 600 mg/day 2

Dosing in Renal Impairment

• Normal renal function (CrCl >50 mL/min): 100% of recommended dose
• Impaired renal function (CrCl ≤50 mL/min, no dialysis): 50% of recommended dose
• Hemodialysis: 100% of recommended dose after each hemodialysis 2

Administration Considerations

• Oral absorption is rapid and nearly complete (>90%)
• Same daily dose can be used for oral and intravenous administration 2
• Can be taken with or without food 2
• For most infections, a loading dose of twice the daily dose is recommended on the first day to achieve steady-state concentrations by the second day 2

Common Pitfalls and Caveats

1. Inadequate treatment duration: Insufficient treatment periods may lead to recurrence of active infection 2
2. Species-specific considerations:
   • For C. glabrata infections, echinocandins are preferred over fluconazole 1
   • For C. krusei infections, fluconazole is not effective due to intrinsic resistance 1
3. Monitoring: Liver function tests should be monitored during extended therapy 3
4. Drug interactions: Fluconazole has significant interactions with many medications due to CYP450 inhibition
5. Recurrent infections: Patients with history of recurrent infections have significantly lower response rates to fluconazole therapy 4

By following these evidence-based dosing recommendations, clinicians can optimize treatment outcomes while minimizing adverse effects for patients with various fungal infections.