Antifungal (Polyene — Topical GI) Pregnancy: No animal reproductive studies 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. Excretion in human milk is unknown — exercise caution in nursing women.

Nystatin (Oral Suspension)

Brand names: Nystan

Nystatin oral suspension is a topical (non-absorbed) polyene antifungal used to treat and prevent candidal infection of the mouth and oropharynx, such as oral 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 100,000 unit/mL oral suspension (100,000 units) dropped into the mouth four times daily, kept in contact with the affected areas as long as possible

Route: Oral — dropped into the mouth and held in contact with the affected area for as long as possible before swallowing

Frequency: Four times daily

Indication in adults: treatment of denture sores and oral infections caused by Candida albicans. In the prevention and treatment of candidiasis, the dosage 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. Nystatin oral preparations should not be used for treatment of systemic mycoses (§4.4). PAEDIATRIC (non-weight-based, so not captured in paedDose): the SPC states that in intestinal and oral candidosis (thrush) in infants and children, 1 mL should be dropped into the mouth four times a day, and that for prophylaxis in the newborn the suggested dose is 1 mL once daily; the longer the suspension is kept in contact with the affected area before swallowing, the greater the effect. Verify paediatric use against a children's formulary. Note: the US label captured in the bundle (Nyamyc) is a nystatin TOPICAL powder with a different route and indication and was NOT used for this oral suspension entry.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — 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
Contains sucrose — patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine (§4.4)

Side effects

Generally well tolerated by all age groups, even during prolonged use
Nausea (reported occasionally during therapy)
Large oral doses have occasionally produced diarrhoea, gastrointestinal distress, nausea and vomiting
Rash, including urticaria (rare)
Hypersensitivity and angioedema including facial oedema; Stevens-Johnson syndrome (very rare)

Interactions

None known (§4.5)

Clinical monograph

How it works

Nystatin binds to ergosterol in the fungal cell membrane, creating pores that disrupt membrane integrity and cause leakage of intracellular contents and fungal cell death.

Prescribing in practice

It acts only on contact within the gastrointestinal tract and is negligibly absorbed, so it is effective for local oral and gut candidiasis but not for systemic fungal infection.
The suspension should be retained in the mouth in contact with the affected areas before swallowing, and treatment continued for a short period after symptoms resolve to prevent relapse.
It is generally very well tolerated, with occasional gastrointestinal upset or local irritation at higher doses.

Monitoring

Routine monitoring is not required; review response and consider an alternative or investigation for predisposing factors if the infection fails to clear.

Counselling the patient

Hold the liquid in your mouth, swishing it around the affected areas, before swallowing.
Keep taking it for a few days after the soreness clears to stop the infection coming back.
If you wear dentures, clean them well as they can harbour the infection.

Evidence & guidelines

Topical antifungals such as nystatin are an established treatment for oropharyngeal candidiasis, with persistent or recurrent infection prompting a search for underlying causes.

Reference: PHE Guidelines on Candidiasis; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). 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