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Antifungal (Polyene — Topical GI) Pregnancy: Compatible — nystatin not absorbed; safe throughout pregnancy for oral/vaginal candidiasis.

Nystatin (Oral Suspension)

Brand names: Nystan

Adult dose

Dose: Oral candidiasis: 100,000 units (1mL of 100,000 units/mL suspension) four times daily. Hold in mouth for 1 minute before swallowing. Continue for 48 hours after clinical resolution (usually 7–14 days total).
Route: Oral (swish and swallow)
Frequency: Four times daily (after food)
Max: 500,000 units (5mL) four times daily (severe oropharyngeal/oesophageal candidiasis)
Not absorbed from GI tract — purely topical action within mouth and GI lumen. For oropharyngeal candidiasis in immunocompromised patients, denture wearers, or inhaled corticosteroid users. If no response after 7 days — consider fluconazole systemic therapy. Treat oesophageal candidiasis with systemic fluconazole, not nystatin alone.

Paediatric dose

Route: Oral (swish and swallow)
Frequency: Four times daily
Max: 100,000 units per dose
BNF for Children: neonates and infants: 100,000 units QDS (drop onto each side of mouth; for infants, apply to buccal mucosa with dropper before each feed). Children 1 month–17 years: 100,000–500,000 units QDS. Source: BNF for Children 2024.

Dose adjustments

Renal

No dose adjustment required — not systemically absorbed.

Hepatic

No dose adjustment required — not systemically absorbed.

Clinical pearls

  • Not absorbed from GI tract — purely local antifungal effect. Cannot treat systemic or oesophageal candidiasis (use fluconazole systemically).
  • Inhaled corticosteroid thrush: advise patients to rinse mouth with water and spit after every inhaler dose — prevents oropharyngeal candidiasis. Nystatin is treatment if it develops.
  • Denture-related candidiasis: treat both the patient (nystatin suspension QDS) and the dentures (soak in nystatin solution or antifungal denture cream overnight).
  • Immunocompromised patients: nystatin may be insufficient for persistent or severe oropharyngeal candidiasis — escalate to fluconazole 50–100mg OD × 7–14 days.

Contraindications

  • Known hypersensitivity to nystatin or polyene antifungals

Side effects

  • Nausea, vomiting (large doses)
  • Diarrhoea (large doses)
  • Oral irritation (mild)
  • Allergic contact reactions (rare)

Interactions

  • No clinically significant systemic drug interactions (not absorbed)

Monitoring

  • Symptom response (mucosal appearance, symptoms)
  • Consider fluconazole if no improvement in 7 days

Reference: BNFc; BNF 90; BNF for Children 2024; PHE Guidelines on Candidiasis. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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