What is the proper dosage and administration of nystatin (antifungal medication) suspension for treating oral candidiasis (thrush)?

Nystatin Suspension Dosing and Administration for Oral Candidiasis

For mild oral thrush, use nystatin suspension 4-6 mL (400,000-600,000 units) four times daily for 7-14 days, swishing the medication in your mouth for as long as possible (at least 2 minutes) before swallowing, and continue treatment for at least 48 hours after symptoms resolve. 1, 2

Specific Dosing by Age

Adults and Children

• Administer 4-6 mL (400,000-600,000 units) four times daily 2
• Place one-half of the dose in each side of the mouth 2
• Retain in mouth as long as possible before swallowing 2

Infants

• Administer 2 mL (200,000 units) four times daily 2
• Use dropper to place one-half of dose in each side of mouth 2
• Avoid feeding for 5-10 minutes after administration 2
• For premature and low birth weight infants: 1 mL four times daily is effective 2

Critical Administration Technique

The key to nystatin effectiveness is prolonged contact time with oral mucosa:

• Swish thoroughly throughout the mouth for at least 2 minutes, ensuring contact with all affected areas 1
• Swallow the medication rather than spitting it out to treat potential esophageal involvement 1
• Ideally administer after meals and before bedtime 1

Treatment Duration

• Continue for 7-14 days minimum 1, 2
• Extend treatment for at least 48 hours after symptoms disappear and cultures confirm eradication of Candida albicans 1, 2

Important Limitations and When to Switch Therapy

Nystatin suspension has significant limitations you should understand:

Poor Efficacy Compared to Alternatives

• Clinical cure rates with nystatin suspension are only 32-54% compared to 100% with fluconazole in infants 1, 3
• In HIV/AIDS patients, fluconazole achieves 87% clinical cure versus only 52% with nystatin 4
• For moderate-to-severe oral thrush, switch immediately to oral fluconazole 100-200 mg daily for 7-14 days as first-line therapy 1

When Nystatin is NOT Appropriate

• Moderate-to-severe disease: Use fluconazole instead 1
• Immunocompromised patients: Systemic therapy is more appropriate 1
• Esophageal candidiasis: Topical nystatin is inadequate; systemic therapy required 1

Enhancing Nystatin Effectiveness

If you must use nystatin, consider combination therapy:

• Adding nystatin pastilles (200,000 units, 1-2 pastilles four times daily) to the suspension regimen achieves higher cure rates than suspension alone 1, 5
• Pastilles provide prolonged antifungal activity (detectable for at least 5 hours) compared to suspension (rapidly eliminated) 6

Management of Treatment Failure

If nystatin fails after 7-14 days:

• Switch to itraconazole solution 200 mg once daily (effective in two-thirds of fluconazole-refractory cases) 1
• Alternative options include posaconazole suspension, voriconazole, or amphotericin B oral suspension 1

Essential Adjunctive Measures

For denture-related candidiasis:

• Denture disinfection must accompany antifungal therapy or treatment will fail 1, 7
• Reinfection commonly occurs without addressing the denture as a reservoir 7

Special Population Considerations

HIV-Infected Patients

• Antiretroviral therapy is more important than antifungal choice for reducing recurrence rates 1
• For recurrent infections, fluconazole 100 mg three times weekly for chronic suppression 1

Common Pitfall to Avoid

• Do not use nystatin as first-line for moderate-to-severe disease due to suboptimal tolerability and lower efficacy 1
• The most common error is continuing nystatin when fluconazole would be more appropriate 1