What is the appropriate fluconazole dosage for a 14‑year‑old adolescent with an uncomplicated yeast infection (e.g., oral thrush or vulvovaginal candidiasis)?

Fluconazole Dosing for Vaginal Yeast Infection in a 14-Year-Old

A single oral dose of fluconazole 150 mg is the appropriate treatment for a 14-year-old with uncomplicated vulvovaginal candidiasis, as adolescents of this age have drug clearance rates similar to adults and should receive the standard adult dose. 1

Dosing Recommendation

• Standard dose: Fluconazole 150 mg orally as a single dose for uncomplicated vulvovaginal candidiasis, which achieves >90% clinical response rates 1
• The CDC explicitly states that the standard adult dose of 150 mg is appropriate for adolescents age 15 and older, as their drug clearance matches adult pharmacokinetics 1
• A 14-year-old falls within this age range where adult dosing applies, avoiding the weight-based pediatric dosing (12 mg/kg) used in younger children 1
• The FDA-approved dosage for vaginal candidiasis is 150 mg as a single oral dose 2

When to Use This Regimen (Uncomplicated Disease)

This single-dose regimen is appropriate when the infection meets criteria for uncomplicated vulvovaginal candidiasis 1:

• Mild-to-moderate symptoms (pruritus, discharge, dysuria)
• Sporadic or infrequent episodes (<4 per year)
• Likely Candida albicans (most common species)
• Immunocompetent patient (no HIV, uncontrolled diabetes, or immunosuppression)

When Extended Therapy Is Required (Complicated Disease)

Do not use single-dose fluconazole if any of the following apply 1:

• Severe vulvovaginal inflammation (extensive erythema, edema, excoriation, or fissures): Use fluconazole 150 mg every 72 hours for 3 doses (total 450 mg over 6 days) 1
• Recurrent infection (≥4 episodes per year): Requires induction therapy followed by maintenance fluconazole 150 mg weekly for 6 months 1
• Suspected non-albicans species (prior azole failure): Consider boric acid 600 mg intravaginally daily for 14 days instead 1
• Uncontrolled diabetes or immunosuppression: May require 7-14 days of therapy 1

Diagnostic Confirmation Before Treatment

Confirm the diagnosis before prescribing fluconazole to avoid treating the wrong condition 1:

• Perform wet-mount microscopy with 10% KOH to visualize yeast or pseudohyphae 1
• Verify vaginal pH ≤4.5 (elevated pH suggests bacterial vaginosis or trichomoniasis instead) 1
• If wet mount is negative but symptoms persist, obtain vaginal culture 1
• Do not treat asymptomatic colonization, as 10-20% of women harbor Candida without infection 1

Safety and Drug Interactions

• Fluconazole is generally well-tolerated, with mild gastrointestinal side effects (nausea, abdominal pain, headache) in <2% of patients 3, 4
• Check for drug interactions before prescribing 1:
  • Warfarin (can elevate INR and increase bleeding risk)
  • Oral hypoglycemics (risk of hypoglycemia)
  • Phenytoin (risk of toxicity)
  • Calcium-channel blockers, protease inhibitors, calcineurin inhibitors
• Baseline liver tests are not required for single-dose therapy in patients without known hepatic disease 1

Alternative: Topical Azole Therapy

If oral therapy is contraindicated or the patient prefers topical treatment 1:

• Clotrimazole 1% cream 5 g intravaginally daily for 7-14 days
• Miconazole 200 mg suppository daily for 3 days
• Terconazole 0.8% cream 5 g intravaginally daily for 3 days
• These achieve equivalent efficacy (80-90% cure rates) to single-dose fluconazole 1

Management of Treatment Failure

If symptoms persist beyond 5-7 days or recur within 2 months 1:

• Re-evaluate with repeat wet mount and vaginal culture
• Consider non-albicans species, particularly C. glabrata (10-20% of recurrent cases) 5
• C. glabrata is resistant to standard fluconazole and requires boric acid 600 mg intravaginally daily for 14 days 5

Critical Pitfall to Avoid

Do not prescribe fluconazole if the patient is or might be pregnant, as it is associated with spontaneous abortion and congenital malformations 6. Use only 7-day topical azole therapy in pregnancy 6.