What is the preferred oral treatment for uncomplicated vaginal candidiasis in an adult non‑pregnant woman without hepatic impairment or drug interactions?

Best Oral Pill for Yeast Infection

A single 150 mg oral dose of fluconazole is the recommended first-line oral treatment for uncomplicated vaginal candidiasis in adult non-pregnant women. 1, 2, 3

When to Use Single-Dose Fluconazole 150 mg

This regimen is appropriate when all of the following criteria are met:

• Mild-to-moderate symptoms (pruritus, discharge, dysuria, dyspareunia without severe vulvar edema, excoriation, or fissures) 1, 2
• Sporadic or infrequent episodes (fewer than 4 episodes per year) 1, 2
• Likely Candida albicans infection (no prior azole treatment failure suggesting resistant species) 1, 2
• Immunocompetent host (no HIV, uncontrolled diabetes, or systemic immunosuppression) 1, 2
• Not pregnant or breastfeeding 4

The single 150 mg dose achieves clinical cure rates exceeding 90% and mycological eradication in 72–77% of patients at 5–16 days post-treatment. 5, 6, 7 Long-term efficacy (27–62 days) remains high at 88–93% clinical cure. 5, 6, 8

When Single-Dose Fluconazole Is Insufficient

Severe Acute Disease

For extensive vulvar erythema, edema, excoriation, or fissure formation, prescribe fluconazole 150 mg every 72 hours for a total of 2–3 doses (450 mg over 6 days). 1, 2 Single-dose therapy is inadequate for severe presentations. 1, 2

Recurrent Vulvovaginal Candidiasis (≥4 Episodes/Year)

Use a two-phase protocol: 1, 2

1. Induction: 10–14 days of topical azole therapy or fluconazole 150 mg every 72 hours for 3 doses 1, 2
2. Maintenance: Fluconazole 150 mg once weekly for 6 months 1, 2

This maintenance regimen controls symptoms in >90% of women but is not curative; 40–50% experience recurrence after cessation. 1

Suspected Non-Albicans Species

If prior azole failure or known C. glabrata infection, do not use fluconazole. 1, 9 Instead, prescribe intravaginal boric acid 600 mg daily for 14 days (first-line for C. glabrata). 1, 9 Alternative options include nystatin suppositories 100,000 units daily for 14 days or compounded topical 17% flucytosine ± 3% amphotericin B cream for 14 days. 1, 9

Critical Diagnostic Steps Before Prescribing

Do not prescribe empirically. Confirm the diagnosis with: 1, 2

• Wet-mount microscopy using 10% potassium hydroxide to visualize yeast or pseudohyphae 1, 2
• Vaginal pH measurement (should be ≤4.5; elevated pH suggests bacterial vaginosis or trichomoniasis) 1, 2
• Vaginal culture if wet mount is negative but symptoms persist, to identify species and guide therapy 1, 2

Symptoms of pruritus, discharge, and dysuria are nonspecific and can result from multiple infectious and noninfectious causes. 1 Asymptomatic colonization (present in 10–20% of women) should never be treated. 2, 10

Drug Interactions and Safety Considerations

Screen for the following interactions before prescribing fluconazole: 2, 10

• Warfarin: Risk of elevated INR and bleeding 2
• Oral hypoglycemics: Risk of hypoglycemia 2
• Phenytoin: Risk of toxicity 2
• Calcium-channel blockers, protease inhibitors, tacrolimus, cyclosporine: Increased drug levels 2

Avoid fluconazole in pregnancy due to associations with spontaneous abortion and congenital malformations; use 7-day topical azole therapy instead. 2, 10 Baseline liver function tests are not required for single-dose therapy in patients without known hepatic disease. 2

Management of Treatment Failure

If symptoms persist beyond 5–7 days or recur within 2 months: 2, 10

• Obtain vaginal culture to identify non-albicans species (especially C. glabrata, which accounts for 10–20% of recurrent cases) 1, 9, 10
• Consider antifungal susceptibility testing if C. glabrata is isolated 9
• Switch to boric acid 600 mg intravaginally daily for 14 days for confirmed azole-resistant organisms 1, 9

Comparison with Topical Therapy

Oral fluconazole 150 mg single dose and topical azoles (e.g., clotrimazole 1% cream for 7 days, miconazole 200 mg suppository for 3 days) achieve equivalent clinical cure rates (>90%) and mycological eradication (72–77%). 1, 2, 7, 8 However, fluconazole relieves symptoms more rapidly and offers superior patient acceptability and compliance. 5, 8 The choice between oral and topical therapy should be guided by patient preference, contraindications (pregnancy), and severity of disease. 1, 2

Common Pitfalls to Avoid

• Do not treat asymptomatic colonization – 10–20% of women harbor Candida without infection. 2, 10
• Do not use single-dose therapy for severe disease – extended regimens are required. 1, 2
• Do not prescribe fluconazole for confirmed C. glabrata – it is ineffective at standard doses. 1, 9
• Do not assume all vaginal symptoms are yeast – confirm diagnosis microscopically before treatment. 1, 2
• Do not ignore recurrent episodes – ≥4 episodes/year require maintenance suppressive therapy. 1, 2