Antifungal — polyene (topical oral candidiasis treatment) Pregnancy: Animal reproductive studies have not been conducted; it is not known whether nystatin can cause foetal harm, although absorption from the gastrointestinal tract is negligible — prescribe during pregnancy only if the potential benefits outweigh the potential risk to the foetus. It is not known whether nystatin is excreted in human milk; caution should be exercised in a nursing woman (§4.6).

Nystatin 100,000 units/mL Oral Suspension

Brand names: Nystan

Nystatin oral suspension is a topical antifungal used to treat oral and oropharyngeal candidiasis (thrush).

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 1 mL of the suspension (strength 100,000 units/mL)

Route: Oral — dropped into the mouth and kept in contact with the affected areas as long as possible before swallowing

Frequency: Four times daily

Adults, for the treatment of denture sores and oral infections caused by C. albicans: 1 mL of the suspension should be dropped into the mouth four times daily and kept in contact with the affected areas as long as possible (§4.2). In the prevention and treatment of candidiasis the regimen should be continued for at least 48 hours after symptoms have disappeared. If signs and symptoms worsen or persist beyond 14 days of treatment, the patient should be re-evaluated and alternative therapy considered. Older people: no specific dosage recommendations or precautions. Paediatric wording as stated in §4.2 (not a per-kg dose): in intestinal and oral candidosis (thrush) in infants and children, 1 mL should be dropped into the mouth four times a day; for prophylaxis in the newborn the suggested dose is 1 mL once daily — verify against a children's formulary before use. Nystatin oral preparations should not be used for treatment of systemic mycoses (§4.4). Excipients: contains sucrose, ethanol (228 mg per 30 mL) and methyl/propyl parahydroxybenzoate (§4.4). Source product: Nystatin 100,000 unit/ml Oral suspension (Ready Mixed) UK SPC.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients (§4.3)

Side effects

Nausea — reported occasionally during therapy (§4.8)
Large oral doses have occasionally produced diarrhoea, gastrointestinal distress, nausea and vomiting (§4.8)
Rash, including urticaria — reported rarely (§4.8)
Stevens-Johnson syndrome — reported very rarely (§4.8)
Hypersensitivity and angioedema, including facial oedema (§4.8)
If irritation or sensitisation develops, treatment should be discontinued (§4.8)

Interactions

None known (§4.5)

Clinical monograph

How it works

It binds to ergosterol in the fungal cell membrane, creating pores that cause leakage of cell contents and fungal cell death; it acts locally within the mouth and gut.

Prescribing in practice

It is essentially not absorbed from the gut, so systemic effects are minimal and it acts only on contact — adequate mouth exposure is essential for efficacy.
Hold the suspension in the mouth, in contact with the affected areas, before swallowing, and use after food.
Continue treatment for the full course, typically for a period after lesions clear, to prevent relapse.

Monitoring

Routine laboratory monitoring is not required; review clinically for resolution of lesions and consider an alternative or underlying-cause review if there is no response.

Counselling the patient

Keep the liquid in your mouth and swish it around the affected areas for as long as you can before swallowing.
Use it after food and avoid eating or drinking for a short time afterwards so it stays in contact.
Finish the whole course even once the white patches have cleared.

Evidence & guidelines

A long-established topical treatment for oral candidiasis recommended in UK primary-care guidance, with good local efficacy and minimal systemic exposure.

Reference: NICE CKS Oral Candidiasis; PHE Candidiasis Guidelines; Confirm identity and dosing against the manufacturer SPC (eMC) and NICE. Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways