Nystatin Dosing for a 2-Week-Old Infant
For a 2-week-old infant with oral candidiasis (thrush), administer nystatin oral suspension 1 mL (100,000 units) four times daily, placing one-half of the dose in each side of the mouth and avoiding feeding for 5-10 minutes. 1
Standard Treatment Dosing
The FDA-approved dosing for infants specifically states:
- Dose: 2 mL (200,000 units) four times daily for standard infant dosing 1
- However, for premature and low birth weight infants: 1 mL (100,000 units) four times daily is effective 1
Given that a 2-week-old infant may still be of low birth weight or premature, starting with 1 mL four times daily is appropriate and supported by clinical studies 1, 2
Administration Technique
- Use a dropper to place one-half of the dose in each side of the mouth 1
- Avoid feeding for 5-10 minutes after administration to allow adequate contact time 1
- The preparation should be retained in the mouth as long as possible before swallowing 1
Treatment Duration
- Continue for at least 48 hours after symptoms disappear and cultures confirm eradication of Candida 1
- Standard treatment duration is 7-14 days 3, 4, 5
Prophylaxis Dosing (Different Context)
If this 2-week-old is being considered for prophylaxis (not treatment) in a high-risk NICU setting:
- 100,000 units (1 mL) three times daily for 6 weeks is recommended for neonates <1500g in nurseries with high invasive candidiasis rates 3, 5
- This applies specifically to birth weight <1500g in settings where fluconazole is unavailable or contraindicated 3
Important Clinical Considerations
Efficacy concerns: Nystatin has lower cure rates compared to fluconazole (32% vs 100% in one study), with frequent recurrences 6. If treatment fails after 7-14 days, consider switching to fluconazole 3-6 mg/kg once daily 4, 6
Safety monitoring: While generally safe, be aware of potential concerns for intestinal damage and necrotizing enterocolitis in premature infants, though these are primarily theoretical concerns from prophylaxis studies 3
Maternal treatment: If the infant is breastfeeding and has oral thrush, simultaneous treatment of the mother's nipples with miconazole cream after each feeding is recommended to prevent reinfection 4