What treatment options are available for a 32-week pregnant patient with a history of thrush, previously treated with nystatin (Nilstat), who is now experiencing burning and itching symptoms unresponsive to over-the-counter treatments?

Treatment of Thrush in a 32-Week Pregnant Patient

For this 32-week pregnant patient with suspected vaginal thrush unresponsive to over-the-counter treatments, prescribe a topical azole antifungal (clotrimazole 1% cream 5g intravaginally or miconazole 2% cream 5g intravaginally) for 7 days, as this is the CDC-recommended first-line treatment for vaginal candidiasis during pregnancy. 1

Diagnostic Confirmation

Before prescribing, confirm the diagnosis through:

• Clinical symptoms: pruritus, white discharge, vulvar erythema, and burning 1
• Normal vaginal pH (≤4.5) 1
• If possible via telehealth, recommend wet mount with 10% KOH showing yeasts or pseudohyphae, or positive culture 1

First-Line Treatment Options

The CDC recommends the following topical azole regimens for pregnant patients 1:

• Clotrimazole 1% cream 5g intravaginally for 7-14 days 1
• Clotrimazole 100mg vaginal tablet daily for 7 days 1
• Miconazole 2% cream 5g intravaginally for 7 days 1
• Miconazole 100mg vaginal suppository daily for 7 days 1
• Terconazole 0.4% cream 5g intravaginally for 7 days 1

Seven-day treatment courses are more effective than shorter regimens during pregnancy. 1, 2 Research demonstrates that 4-day treatments are significantly less effective than 7-day courses (odds ratio 11.7) 2, while 7-day and 14-day regimens show comparable efficacy 2.

Critical Treatment Considerations

Do NOT prescribe nystatin (Nilstat) as first-line therapy, despite the patient's previous use. 1 Topical azoles achieve 80-90% cure rates and are significantly more effective than nystatin in pregnancy 1, 2. A Cochrane review of five trials confirmed imidazole drugs are substantially superior to nystatin for vaginal candidiasis in pregnancy (odds ratio 0.21) 2.

Oral fluconazole is contraindicated during pregnancy and should not be prescribed for this patient, even though it would be appropriate for non-pregnant individuals 1.

Pregnancy-Specific Guidance

• Topical azole antifungals are FDA Pregnancy Category C, but extensive clinical experience supports their safety profile 3
• The potential benefit to the mother outweighs potential fetal risk when treating symptomatic candidiasis 3
• Treating asymptomatic colonization is not recommended, as 10-20% of women normally harbor Candida without requiring treatment 1

Partner Management

• Treatment of sexual partners is not recommended, as vulvovaginal candidiasis is not typically sexually transmitted 1
• Partners with symptomatic balanitis may benefit from topical antifungal treatment 1

Follow-Up Instructions

• Complete the full 7-day course even if symptoms improve earlier to prevent treatment failure 4
• Return for follow-up only if symptoms persist after completing treatment or recur 4, 1
• Persistent symptoms warrant ruling out resistant infection or alternative diagnoses 1

Common Pitfalls to Avoid

• Premature discontinuation of therapy leads to treatment failure 4
• Prescribing shorter courses (3-4 days) results in significantly higher failure rates in pregnancy 2
• Using nystatin as first-line therapy when topical azoles are far more effective 1, 2
• Prescribing oral fluconazole during pregnancy 1