Oral Fluconazole Dosing for Vaginal Yeast Infection
For uncomplicated vaginal candidiasis in a non-pregnant adult woman, administer a single oral dose of fluconazole 150 mg. This regimen achieves >90% clinical cure rates and is the FDA-approved, guideline-recommended first-line therapy 1, 2.
Standard Single-Dose Regimen
- Fluconazole 150 mg orally as a single dose is the treatment of choice for uncomplicated vaginal candidiasis, providing efficacy equivalent to multi-day topical azole therapy with superior convenience 1, 2.
- Clinical cure or improvement occurs in 92-99% of patients at 5-16 days post-treatment, with mycologic eradication rates of 72-93% 3, 4, 5.
- This single-dose regimen is appropriate when the patient has mild-to-moderate symptoms (pruritus, discharge, dysuria), sporadic episodes (not recurrent), likely Candida albicans infection, and is immunocompetent 3.
When Single-Dose Therapy Is Insufficient
Severe Vulvovaginal Candidiasis
- For extensive vulvar erythema, edema, excoriation, or fissures: fluconazole 150 mg orally every 72 hours for 3 doses (total 450 mg over 6 days) 1, 3, 6.
- Alternatively, use topical azole therapy for 7-14 days 1, 6.
Recurrent Vulvovaginal Candidiasis (≥4 Episodes Per Year)
- Induction phase: fluconazole 150 mg every 72 hours for 3 doses, or topical azole for 10-14 days 1, 6.
- Maintenance phase: fluconazole 150 mg once weekly for 6 months, which controls symptoms in >90% of patients during treatment 1, 6.
- After stopping maintenance therapy, expect 40-50% recurrence rates; median time to recurrence is 10.2 months with maintenance versus 4.0 months without 6.
Diagnostic Confirmation Before Prescribing
- Perform wet mount microscopy with 10% KOH to visualize yeast or pseudohyphae before initiating fluconazole 1, 3, 6.
- Measure vaginal pH: pH ≤4.5 supports candidiasis; pH >4.5 suggests bacterial vaginosis or trichomoniasis 1, 3, 6.
- Obtain vaginal culture if wet mount is negative but symptoms persist 1, 3, 6.
- Symptoms alone (pruritus, discharge) are nonspecific and present in only ~50% of patients who self-diagnose yeast infection; empiric treatment without confirmation leads to misdiagnosis in >50% of cases 6.
Management of Treatment Failure and Non-Albicans Species
- If symptoms persist beyond 5-7 days or recur within 2 months, obtain vaginal culture to identify non-albicans species such as Candida glabrata or C. krusei 3, 6.
- C. glabrata is frequently azole-resistant and accounts for 10-20% of recurrent cases 6.
Alternative Regimens for C. glabrata
- Boric acid 600 mg intravaginal gelatin capsules daily for 14 days (must be compounded by a pharmacist), achieving ~70% clinical and mycologic eradication 1, 6.
- Nystatin 100,000 units intravaginal suppositories daily for 14 days 1, 6.
- Topical 17% flucytosine cream ± 3% amphotericin B cream daily for 14 days (requires compounding) 1, 6.
Critical Drug Interactions and Safety Considerations
- Warfarin: fluconazole potentiates anticoagulant effect, increasing INR and bleeding risk; monitor INR closely 3, 6.
- Oral hypoglycemics: enhanced hypoglycemic effect; monitor blood glucose 6.
- Phenytoin: increased risk of toxicity; monitor levels 6.
- Calcineurin inhibitors (tacrolimus, cyclosporine), protease inhibitors, calcium-channel blockers: fluconazole increases drug levels; dose adjustments may be needed 6.
- Hepatotoxicity: transient transaminase elevations are rare with single-dose therapy; baseline liver tests are not required in patients without known hepatic disease 3, 6.
Common Pitfalls to Avoid
- Do not treat asymptomatic colonization: 10-20% of women harbor Candida without symptoms, and treatment is not indicated 3, 6.
- Do not prescribe empirically without diagnostic confirmation: this leads to misdiagnosis in >50% of cases 6.
- Do not use single-dose therapy for severe or recurrent disease: extended regimens are required 3, 6.
- Do not ignore treatment failure patterns: persistent symptoms may indicate non-albicans species requiring alternative agents 3, 6.