What is the appropriate dosing for fluconazole (Diflucan) orally?

From the Guidelines

For oral diflucan dosing, the recommended dose is 800 mg (12 mg/kg) as a loading dose, followed by 400 mg (6 mg/kg) daily for invasive candidiasis, as stated in the 2016 update by the Infectious Diseases Society of America 1.

Key Considerations

• The dosing regimen may vary depending on the type of candidiasis, with lower doses used for mucosal candidiasis and higher doses for invasive candidiasis.
• Fluconazole is readily absorbed orally, with a bioavailability of approximately 90% of intravenous administration, and its absorption is not affected by food consumption, gastric pH, or disease state 1.
• For patients with creatinine clearance <50 mL/minute, a dose reduction is necessary due to fluconazole's primarily renal elimination 1.

Important Details

• The higher-dose level of 800 mg daily (12 mg/kg) is often recommended for therapy of susceptible C. glabrata infections, although this has not been validated in clinical trials 1.
• Fluconazole achieves high concentrations in the urine, making it the preferred treatment option for symptomatic cystitis, and it also has good penetration into the cerebrospinal fluid (CSF) and vitreous, achieving concentrations of >70% of those in serum 1.
• Common side effects of fluconazole include headache, nausea, abdominal pain, and diarrhea, and it may interact with several medications, including warfarin and oral hypoglycemics.

From the FDA Drug Label

Dosage and Administration in Adults: Single Dose Vaginal candidiasis: The recommended dosage of fluconazole tablets for vaginal candidiasis is 150 mg as a single oral dose. Oropharyngeal candidiasis: The recommended dosage of fluconazole tablets for oropharyngeal candidiasis is 200 mg on the first day, followed by 100 mg once daily. Esophageal candidiasis: The recommended dosage of fluconazole tablets for esophageal candidiasis is 200 mg on the first day, followed by 100 mg once daily. Systemic Candida infections: For systemic Candida infections including candidemia, disseminated candidiasis, and pneumonia, optimal therapeutic dosage and duration of therapy have not been established. Cryptococcal meningitis: The recommended dosage for treatment of acute cryptococcal meningitis is 400 mg on the first day, followed by 200 mg once daily

The oral diflucan dosing is as follows:

• Vaginal candidiasis: 150 mg as a single oral dose
• Oropharyngeal candidiasis: 200 mg on the first day, followed by 100 mg once daily
• Esophageal candidiasis: 200 mg on the first day, followed by 100 mg once daily
• Cryptococcal meningitis: 400 mg on the first day, followed by 200 mg once daily
• Systemic Candida infections: optimal therapeutic dosage and duration of therapy have not been established, but doses of up to 400 mg daily have been used 2

From the Research

Oral Diflucan Dosing

• The dosing of oral Diflucan (fluconazole) for the treatment of oropharyngeal candidiasis has been studied in various clinical trials 3, 4, 5, 6.
• In a study published in 1990, patients with chronic atrophic candidiasis associated with dentures received 50 mg of fluconazole daily for 7 or 14 days, resulting in clinical and mycologic cure rates ranging from 69% to 100% 3.
• Another study published in 2004 discussed the efficacy and safety of fluconazole for the treatment of candidiasis, including oropharyngeal and esophageal candidiasis, but did not provide specific dosing information 4.
• A systematic review published in 2012 examined the effects of interventions to prevent and treat oropharyngeal candidiasis, including the use of antifungals such as fluconazole, but did not provide specific dosing recommendations 5.
• A meta-analysis published in 2022 compared the efficacy and safety of topical antifungal agents, including fluconazole, for the treatment of oral candidiasis in adults and children, and found that fluconazole showed a better clinical response rate than clotrimazole in adults 6.
• While these studies provide information on the use of fluconazole for the treatment of oropharyngeal candidiasis, they do not provide a clear consensus on the optimal dosing regimen 3, 4, 5, 6.

Dosing Regimens

• The studied dosing regimens for oral Diflucan include:
  • 50 mg daily for 7 or 14 days for chronic atrophic candidiasis associated with dentures 3
  • 50 or 200 mg daily for oroesophageal candidiasis associated with chronic mucocutaneous candidiasis 3
  • 50 mg daily for 5 days to 8 weeks for oropharyngeal candidiasis associated with malignancy, therapeutic immunosuppression, AIDS, or AIDS-related complex 3
• It is essential to consult the prescribing information and clinical guidelines for the most up-to-date recommendations on oral Diflucan dosing 3, 4, 5, 6.