What is the appropriate fluconazole dosing for an adult non‑pregnant woman with uncomplicated vulvovaginal candidiasis, including initial and maintenance regimens for recurrent infection and alternatives for pregnancy, hepatic impairment, or inability to take oral medication?

Fluconazole Dosing for Vaginal Candidiasis

For uncomplicated vulvovaginal candidiasis in a non-pregnant adult woman, give a single oral dose of fluconazole 150 mg, which achieves >90% clinical cure rates. 1, 2

Initial Treatment Algorithm

Uncomplicated Disease (First-Line)

• Single dose fluconazole 150 mg orally is the standard regimen for mild-to-moderate symptoms, sporadic episodes, likely Candida albicans infection, and immunocompetent patients. 1, 2
• This achieves 92-99% clinical efficacy at 5-16 days post-treatment and 80-90% clinical cure with 60-77% mycologic eradication at long-term follow-up. 1, 3
• Symptoms resolve more rapidly than with topical agents, and efficacy equals multi-day intravaginal azole therapy. 4

Severe Disease (Extensive Vulvar Involvement)

• Fluconazole 150 mg every 72 hours for 2-3 doses (total 450 mg over 6 days) is required when extensive vulvar erythema, edema, excoriation, or fissure formation is present. 5, 1, 2
• Alternatively, use topical azole therapy for 7-14 days. 5

Recurrent Vulvovaginal Candidiasis (≥4 Episodes/Year)

Induction Phase:

• Fluconazole 150 mg every 72 hours for 3 doses (total 450 mg over 6 days), OR 1, 2
• Topical azole therapy for 10-14 days to achieve mycologic remission before maintenance. 5, 1

Maintenance Phase:

• Fluconazole 150 mg once weekly for 6 months controls symptoms in >90% of patients during treatment. 5, 1, 2
• At 6 months, 90.8% remain disease-free; at 12 months (6 months post-discontinuation), 42.9% remain disease-free versus 21.9% with placebo. 6
• Median time to recurrence is 10.2 months with maintenance versus 4.0 months without. 6
• Expect 30-50% recurrence after discontinuing maintenance therapy. 5, 2

Special Populations and Contraindications

Pregnancy

• Only topical azole therapy applied for 7 days is recommended; oral fluconazole is contraindicated. 5

Hepatic Impairment

• Single-dose fluconazole 150 mg does not require baseline liver testing in patients without known hepatic disease, as transient transaminase elevations are rare. 2
• For maintenance regimens, avoid ketoconazole due to 1 in 10,000-15,000 risk of hepatotoxicity; fluconazole is preferred. 5

Inability to Take Oral Medication

• Use intravaginal clotrimazole 500 mg single tablet, OR 1
• Miconazole 200 mg suppository once daily for 3 days, OR 1
• Terconazole 0.8% cream 5 g intravaginally for 3 days. 1
• These achieve comparable 80-90% clinical cure rates to oral fluconazole. 1

Treatment Failure and Non-Albicans Species

When to Suspect Treatment Failure

• Symptoms persisting beyond 5-7 days or recurring within 2 months warrant re-evaluation with vaginal culture. 1, 2
• C. glabrata and other non-albicans species account for 10-20% of recurrent cases and are frequently azole-resistant. 5, 2

Management of C. glabrata Infection

• Boric acid 600 mg intravaginal gelatin capsules daily for 14 days (compounded) achieves ~70% clinical and mycologic eradication. 5, 2
• Alternative: nystatin 100,000 units intravaginal suppositories daily for 14 days. 5, 2
• Second alternative: topical 17% flucytosine cream ± 3% amphotericin B cream daily for 14 days (requires specialist referral). 5, 2

Critical Diagnostic Confirmation (Avoiding Misdiagnosis)

Before prescribing fluconazole:

• Perform wet mount with 10% KOH to visualize yeast or pseudohyphae. 1, 2
• Measure vaginal pH; pH ≤4.5 supports candidiasis, while pH >4.5 suggests bacterial vaginosis or trichomoniasis. 1, 2
• If wet mount is negative but symptoms persist, obtain vaginal culture. 1, 2
• Symptoms alone (pruritus, discharge, dysuria, dyspareunia) are nonspecific and present in only ~50% of women who self-diagnose yeast infection. 1, 2

Drug Interactions and Safety Monitoring

Significant Interactions Requiring Monitoring

• Warfarin: Fluconazole potentiates anticoagulation, elevating INR and bleeding risk; monitor INR closely. 1, 2
• Oral hypoglycemics: Enhanced hypoglycemic effect increases risk of low blood sugar. 2
• Phenytoin: Increased phenytoin levels and toxicity risk. 2
• Calcineurin inhibitors (tacrolimus/cyclosporine), protease inhibitors, calcium-channel blockers: Fluconazole increases drug levels; dose adjustments may be needed. 2

Adverse Effects

• Gastrointestinal symptoms (nausea, abdominal discomfort) are most common, generally mild and transient. 3, 7
• Headache rarely necessitates discontinuation. 6

Common Pitfalls to Avoid

• Do not treat asymptomatic colonization: 10-20% of women harbor Candida without symptoms; treatment is not indicated. 1, 2
• Do not prescribe empirically without diagnostic confirmation: Empiric treatment leads to misdiagnosis in >50% of cases. 2
• Do not use single-dose therapy for severe or recurrent disease: Extended regimens are mandatory. 2
• Do not ignore patterns of treatment failure: Persistent symptoms may indicate non-albicans species requiring alternative agents. 1, 2
• Do not use fluconazole in pregnancy: Only 7-day topical azole therapy is safe. 5