What is the recommended dosage of Fluconazole (an antifungal medication)?

From the Guidelines

Fluconazole dosing typically ranges from 50-400mg daily depending on the infection being treated, with a loading dose of 800 mg (12 mg/kg) followed by an average daily dose of 400 mg (6 mg/kg) for invasive candidiasis, as recommended by the Infectious Diseases Society of America 1.

Key Considerations

• For vaginal candidiasis, a single 150mg oral dose is usually sufficient.
• For oropharyngeal candidiasis, 200mg on day one followed by 100mg daily for 1-2 weeks is recommended.
• Esophageal candidiasis requires 200mg on day one followed by 100mg daily for 2-3 weeks.
• For systemic candidiasis, doses of 400mg on day one followed by 200mg daily for at least 2 weeks after symptom resolution are needed.
• Cryptococcal meningitis requires higher doses of 400mg daily for 10-12 weeks.

Dosage Adjustments

• Dosage adjustments are necessary for patients with renal impairment, with recommendations to reduce the dose by 50% if creatinine clearance is below 50 ml/min, as fluconazole elimination is almost entirely renal 1.

Mechanism of Action

• Fluconazole works by inhibiting fungal cytochrome P450 enzymes, preventing the synthesis of ergosterol, an essential component of fungal cell membranes, allowing it to be effective against many Candida species and Cryptococcus, though some species like Candida glabrata and Candida krusei may show resistance 1.

Important Notes

• The choice of antifungal therapy should be based on the specific species of Candida, the severity of the infection, and the patient's underlying medical conditions, as well as potential drug interactions and side effects 1.
• Other triazoles, such as itraconazole, voriconazole, posaconazole, and isavuconazole, may also be effective against Candida species, but their use is often reserved for specific situations, such as fluconazole-resistant infections or CNS involvement 1.

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. The daily dose of fluconazole tablets for the treatment of infections other than vaginal candidiasis should be based on the infecting organism and the patient’s response to therapy 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 recommended dosage of fluconazole varies based on the type of infection being treated.

• 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

Fluconazole Dosage

• The dosage of fluconazole varies depending on the type of infection being treated 3, 4, 5.
• For the treatment of symptomatic fungal urinary tract infection (UTI), a fluconazole 200-mg loading dose followed by 100 mg/d for at least four days appears to be the most appropriate dose 5.
• In patients with AIDS, fluconazole is the present drug of choice as maintenance therapy against cryptococcal meningitis, and is a preferred agent for secondary prophylaxis against candidal infections 4.
• The drug is generally well tolerated and infrequently associated with serious adverse effects or laboratory test abnormalities 3.
• Extensive clinical trials document clinical efficacy in candidiasis, including oropharyngeal, esophageal, and disseminated forms, as well as in acute or suppressive therapy of cryptoccal meningitis 3.

Dosage Considerations

• The optimal dosing of fluconazole, including the most appropriate dose in non-albicans species of candida, as well as the optimal duration of therapy, remains unclear and requires further study 5.
• Issues yet to be clarified include the use of fluconazole in children with AIDS, its efficacy against other fungal infections encountered in immunocompromised patients, and whether the drug influences mortality 4.
• The incidence of adverse events appears to be somewhat higher in patients with AIDS compared with HIV-negative cohorts, but the qualitative pattern of events is similar 4.