What is the recommended dose of nystatin (antifungal medication) for a 9-month-old infant with thrush?

Nystatin Dosing for Oral Thrush in a 9-Month-Old Infant

For a 9-month-old infant with thrush, administer nystatin oral suspension 2 mL (200,000 units) four times daily for 7-14 days, using a dropper to place half the dose in each side of the mouth. 1

Standard Dosing Regimen

• The FDA-approved dose for infants is 2 mL (200,000 units) four times daily, which should be retained in the mouth as long as possible before swallowing 1
• Use a dropper to place one-half of the dose (1 mL) in each side of the mouth and avoid feeding for 5-10 minutes to maximize contact time with oral mucosa 1
• Continue treatment for at least 48 hours after symptoms have disappeared and cultures confirm eradication of Candida 1

Treatment Duration

• The American Academy of Pediatrics recommends 7-14 days of treatment for uncomplicated oral candidiasis in infants 2
• The typical duration is 7-14 days, with continuation for at least 48 hours after complete symptom resolution to prevent recurrence 2, 1

Administration Technique

• Apply the suspension directly to the affected areas inside the mouth using the dropper 1
• Ensure adequate contact time by avoiding feeding for 5-10 minutes after administration 1
• Administer after feedings when possible to maximize mucosal contact time 2

Important Clinical Considerations

• If breastfeeding is involved, simultaneously treat the mother by applying miconazole cream to nipples/areola after each feeding to prevent reinfection 2
• The most common cause of treatment failure is premature discontinuation when symptoms improve but before mycological cure is achieved 3
• Confirm true treatment failure versus inadequate prior treatment (incomplete courses or inadequate contact time) before considering resistance 3

When Nystatin Fails

• If nystatin fails after a complete 7-14 day course, switch to oral fluconazole 3-6 mg/kg once daily for 7-14 days as the first-line alternative 2, 3
• Fluconazole achieves clinical cure rates of 91-100% versus 32-51% for nystatin in pediatric populations 3, 4
• Miconazole oral gel 15 mg every 8 hours is another alternative with clinical cure rates of 85.1% compared to nystatin's 42.8-48.5%, though there are concerns about generating triazole resistance 2, 5

Common Pitfalls to Avoid

• Do not stop treatment when symptoms improve—continue for the full prescribed duration and at least 48 hours after complete resolution 1, 3
• Ensure adequate contact time with oral mucosa; inadequate contact is a frequent cause of apparent treatment failure 3
• Investigate predisposing factors if treatment fails, including immunodeficiency, diabetes, chronic steroid use, or frequent antibiotic exposure 3