What are the uses of fluconazole (Diflucan)?

Fluconazole Uses and Indications

Fluconazole is indicated for treating vaginal candidiasis, oropharyngeal and esophageal candidiasis, urinary tract candidiasis, systemic Candida infections (including candidemia, disseminated candidiasis, and pneumonia), cryptococcal meningitis, and for prophylaxis in bone marrow transplant patients receiving cytotoxic chemotherapy or radiation. 1

FDA-Approved Indications

Fluconazole is approved for the following conditions 1:

• Vaginal candidiasis (vaginal yeast infections due to Candida)
• Oropharyngeal and esophageal candidiasis
• Candida urinary tract infections
• Peritonitis due to Candida
• Systemic Candida infections including candidemia, disseminated candidiasis, and pneumonia
• Cryptococcal meningitis
• Prophylaxis to decrease candidiasis incidence in bone marrow transplant patients receiving cytotoxic chemotherapy and/or radiation therapy

Specific Clinical Uses by Site of Infection

Mucosal Candidiasis

• Oropharyngeal candidiasis: 100-200 mg daily for 7-14 days for moderate to severe disease 2, with topical agents preferred for mild cases 2
• Esophageal candidiasis: 200-400 mg daily for 14-21 days 3, 2
• Vulvovaginal candidiasis: Single 150 mg oral dose 3, with clinical efficacy rates of 92-99% at short-term evaluation 4

Invasive Candidiasis

• Candidemia and disseminated candidiasis: Loading dose of 800 mg (12 mg/kg) on day 1, followed by 400 mg (6 mg/kg) daily for 2 weeks after documented clearance from bloodstream 3, 2
• Chronic disseminated candidiasis: 400 mg (6 mg/kg) daily until lesions resolve on imaging, typically 3-6 months 3, 2
• Candida endophthalmitis: 400-800 mg daily for at least 4-6 weeks as an alternative to amphotericin B 5, 3

Urinary Tract Infections

• Symptomatic cystitis: 200 mg (3 mg/kg) daily for 14 days 3, 2
• Pyelonephritis: 200-400 mg (3-6 mg/kg) daily for 14 days 3, 2
• Fluconazole achieves urine concentrations 10-20 times serum levels, making it the preferred treatment for symptomatic cystitis 5

Central Nervous System Infections

• CNS candidiasis: 400-800 mg (6-12 mg/kg) daily 3, 2, reserved for patients unable to tolerate amphotericin B 5
• Fluconazole achieves CSF concentrations >70% of serum levels, providing excellent CNS penetration 5
• Cryptococcal meningitis: Fluconazole is effective for both acute treatment and maintenance therapy 5, 1, 6

Osteoarticular Infections

• Candida osteomyelitis: 400 mg (6 mg/kg) daily for 6-12 months 3, with surgical debridement frequently necessary 3

Critical Species Considerations

Fluconazole has NO activity against Candida krusei and variable activity against C. glabrata—always confirm susceptibility before use. 3, 2

• For C. parapsilosis, fluconazole is appropriate; consider switching from echinocandin if initially used 3
• For C. glabrata, only use after confirming susceptibility with negative follow-up cultures 3
• For C. krusei, use echinocandins or amphotericin B instead 3
• Voriconazole should be considered for rare cases of voriconazole-susceptible C. glabrata or C. krusei after initial amphotericin B therapy 5

Additional Clinical Applications

Dermatologic Infections

• Tinea infections: Fluconazole is a second-line or alternative agent reserved for refractory cases when first-line therapies (terbinafine, griseofulvin) have failed 7
• Onychomycosis: 150 mg once weekly for 6-12 months 8
• Cutaneous mycoses (tinea, pityriasis): 50-150 mg for weeks to months with >90% clinical cure rates 8

Critical licensing caveat: Fluconazole is NOT licensed for tinea treatment in children <10 years in the U.K., though it is licensed in Germany for children >1 year 7

Prophylaxis

• Bone marrow transplant patients: 400 mg once daily during cytotoxic chemotherapy and/or radiation therapy 3, 1
• Prophylaxis in HIV patients with CD4+ counts <150 cells/mm³ reduces oropharyngeal candidiasis episodes without increasing clinically significant resistance when combined with antiretroviral therapy 5

Important Clinical Pitfalls to Avoid

• Inadequate treatment duration leads to relapse—continue until clinical and laboratory parameters indicate complete resolution 3
• Central venous catheter removal is strongly recommended for patients with candidemia 3
• Do not use fluconazole as first-line therapy for CNS candidiasis—amphotericin B with or without flucytosine is preferred 5
• Resistance is particularly problematic in patients with recurrent or chronic infections; for fluconazole-resistant species, use alternative antifungals (echinocandins, amphotericin B, voriconazole) 3
• Candida isolated from respiratory secretions usually represents colonization, not infection, and rarely requires treatment 2
• Fluconazole does not accumulate in active form in urine in sufficient concentrations when using lipid formulations, so avoid these for urinary tract infections 5

Drug Interactions and Safety

• Fluconazole has significant drug interactions including enhanced toxicity with warfarin, certain antihistamines, and antipsychotics 7
• Monitor patients on oral hypoglycemics as fluconazole inhibits tolbutamide metabolism 9
• Fluconazole inhibits cytochrome P450 enzymes, requiring careful evaluation of drug interactions, particularly with antiretroviral drugs 5