What is the recommended dosage of Nystatin (antifungal medication) for oral candidiasis (thrush)?

From the Guidelines

Nystatin suspension (100,000 U/mL) should be administered at a dose of 4–6 mL 4 times daily for 7–14 days for the treatment of mild oral thrush. This recommendation is based on strong evidence from the Infectious Diseases Society of America's 2016 clinical practice guideline for the management of candidiasis 1. The guideline suggests that nystatin suspension is an alternative treatment for mild disease, in addition to clotrimazole troches and miconazole mucoadhesive buccal tablets.

Key Considerations

• The treatment duration should be at least 7-14 days and should extend at least 48 hours after symptoms resolve.
• For infants and young children, the dosage is typically 100,000 units (1 ml) four times daily, applied with a clean finger to coat the inside of the mouth.
• Nystatin works by binding to ergosterol in the fungal cell membrane, creating pores that lead to cell death of Candida species.
• The medication is generally well-tolerated with minimal systemic absorption, though some patients may experience mild gastrointestinal upset, nausea, or an unpleasant taste.

Adjunctive Measures

• Good oral hygiene and proper denture care (if applicable) are important adjunctive measures during treatment.
• For persistent or recurrent thrush, underlying causes such as immunosuppression, diabetes, or continued use of inhaled corticosteroids should be addressed.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Infants: 2 mL (200,000 units) four times daily (in infants and young children, use dropper to place one-half of dose in each side of mouth and avoid feeding for 5 to 10 minutes). NOTE: Limited clinical studies in premature and low birth weight infants indicate that 1 mL four times daily is effective. Children and Adults: 4 to 6 mL (400,000 to 600,000 units) four times daily (one-half of dose in each side of mouth). The recommended dosage of nystatin for thrush is:

• Infants: 2 mL (200,000 units) four times daily
• Premature and low birth weight infants: 1 mL four times daily
• Children and Adults: 4 to 6 mL (400,000 to 600,000 units) four times daily 2

From the Research

Nystatin Dosage for Thrush

• The optimal dosage of nystatin for thrush is not explicitly stated in the provided studies, but the efficacy of different formulations and dosages is discussed 3.
• A study found that nystatin pastilles at a dose of 400,000 IU resulted in a significantly higher mycological cure rate than that administered at a dose of 200,000 IU 3.
• The same study suggested that treatment with nystatin pastilles for 4 weeks seemed to have better clinical efficacy than treatment for 2 weeks 3.
• Another study compared the efficacy of different antifungal drugs, including nystatin, and found that miconazole oral gel, fluconazole, and ketoconazole were better than nystatin in reducing the mycological cure rate in oral candidiasis 4.
• The network meta-analysis showed that nystatin had an odds ratio (OR) of 2.50 (95% CrI: 1.43-3.57) in reducing the mycological cure rate in oral candidiasis, which was lower than that of some other antifungal drugs, such as fluconazole (OR=2.40,95% CrI: 1.10-3.80) and miconazole oral gel (OR=2.90,95% CrI: 1.70-4.30) 4.

Comparison with Other Antifungal Drugs

• Nystatin is often compared to other antifungal drugs, such as fluconazole, miconazole, and clotrimazole, in terms of efficacy and safety 5, 6, 4.
• A case report described a patient with refractory oral candidiasis who was treated with fluconazole after failing to respond to nystatin, clotrimazole, and ketoconazole, and obtained immediate relief without associated adverse effects 7.
• The studies suggest that the choice of antifungal drug and dosage may depend on the specific clinical situation and patient factors, such as the severity of the infection and the presence of underlying medical conditions 5, 6, 3, 4.