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Polyene antifungal Pregnancy: Section 4.6 verbatim: 'Animal reproductive studies have not been conducted with nystatin. It is not known whether nystatin can cause foetal harm when administered to a pregnant woman or can affect reproductive capacity, however absorption of nystatin from the gastro-intestinal tract is negligible. Nystatin should be prescribed during pregnancy only if the potential benefits to be derived outweigh the potential risk to the foetus.' Breast-feeding verbatim: 'It is not known whether nystatin is excreted in human milk. Although gastrointestinal absorption is insignificant, caution should be exercised when nystatin is prescribed for a nursing woman.'

Nystatin

Brand names: Nystan

A polyene antifungal used topically and orally (as a non-absorbed oral suspension) to treat and prevent candidal infections of the mouth, throat and gastrointestinal tract.

Adult dose

Dose: 1 mL of Nystatin 100,000 unit/ml oral suspension - that is 100,000 units per dose - dropped into the mouth. Section 4.2 verbatim: 'For the treatment of denture sores, and oral infections in adults caused by C.albicans, 1 ml of the suspension should be dropped into the mouth four times daily; it should be kept in contact with the affected areas as long as possible.' The strength behind the 1 mL volume is pinned by the product name itself: 100,000 units per mL.
Route: Oral - the suspension is dropped into the mouth and held in contact with the affected area as long as possible before swallowing. Section 4.4 verbatim: 'Nystatin oral preparations should not be used for treatment of systemic mycoses.'
Frequency: Four times daily. Duration, section 4.2 verbatim: 'In the prevention and treatment of candidiasis, the dosage regimen for nystatin 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 reevaluated, and alternate therapy considered.'
Max: Not stated - this SPC gives no maximum dose, no maximum daily total and no dose ceiling for the oral suspension. The undesirable-effects section notes only that 'Large oral doses of Nystatin have occasionally produced diarrhoea, gastrointestinal distress, nausea and vomiting', which is an adverse-effect statement and not a stated ceiling.
SCOPE: this draft covers the page's primary indication and route - oral candidiasis treated with the oral suspension, which is what the fetched UK SPC doses. The page's secondary 'Topical' route is NOT covered: the only topical source in this bundle is the US Nyamyc dusting powder, a different product under a different regulator, and its directions are deliberately not transferred here. || OLDER PEOPLE (section 4.2 verbatim): 'No specific dosage recommendations or precautions.' || EXCIPIENTS (section 4.4 verbatim): 'Nystatin Oral Suspension contains sucrose'; 'This medicine contains 228 mg of alcohol (ethanol) in each 30 ml which is equivalent to 0.76 g in 100 ml. The amount in 1 ml of this medicine is equivalent to less than 0.2 ml beer or 0.1 ml wine. The small amount of alcohol in this medicine will not have any noticeable effect.'; 'This medicinal product contains methyl parahydroxybenzoate (E218) and propyl parahydroxybenzoate (E216) which may cause allergic reactions (possibly delayed).'; 'This medicine contains less than 1 mmol sodium (23 mg) per dose, i.e. essentially "sodium free".' || INTERACTIONS (section 4.5 verbatim): 'None known.'

Paediatric dose

Route: Oral - dropped into the mouth and kept in contact with the affected area as long as possible before swallowing
Frequency: Four times a day for treatment of intestinal and oral candidosis; once daily for prophylaxis in the newborn
Max: Not stated - no paediatric maximum dose or daily ceiling appears anywhere in this SPC.
FIXED DOSE, NOT WEIGHT-BASED - dosePerKg is null because this SPC gives no mg/kg or units/kg figure at any age; do not derive one. Section 4.2 verbatim: 'Children: In intestinal and oral candidosis (thrush) in infants and children, 1 ml should be dropped into the mouth four times a day. The longer the suspension is kept in contact with the affected area in the mouth, before swallowing, the greater will be its effect. For prophylaxis in the newborn the suggested dose is 1 ml once daily.' 1 mL of this product is 100,000 units (product name: 'Nystatin 100,000 unit/ml Oral suspension'). concentration is null because this product's strength is expressed in units per mL, not milligrams per mL, so there is no mg/mL figure in the source for a volume calculation to divide by. Duration as for adults: continue for at least 48 hours after symptoms have disappeared, and reassess if signs and symptoms worsen or persist beyond 14 days of treatment. Verify paediatric use against a children's formulary.

Dose adjustments

Renal

Not stated - no renal-impairment dosing statement appears in the fetched sections of this SPC (4.2, 4.3, 4.4, 4.5, 4.6, 4.8). Section 4.6 records that 'absorption of nystatin from the gastro-intestinal tract is negligible', but the SPC draws no dosing conclusion from that and none is inferred here. Verify against the full SPC.

Hepatic

Not stated - no hepatic-impairment dosing statement appears in the fetched sections of this SPC. Verify against the full SPC.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Section 4.3 verbatim: 'Hypersensitivity to the active substance(s) or to any of the excipients listed in section 6.1.'
  • Not listed in section 4.3 but an absolute bar in section 4.4 because the suspension contains sucrose: 'Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.'
  • Not a contraindication but a use restriction (section 4.4): 'Nystatin oral preparations should not be used for treatment of systemic mycoses.'

Side effects

  • Section 4.8 overall: 'Nystatin is generally well tolerated by all age groups, even during prolonged use.'
  • Nausea - 'has been reported occasionally during therapy' (section 4.8).
  • Diarrhoea, gastrointestinal distress, nausea and vomiting with large oral doses (section 4.8).
  • Rash, including urticaria - reported rarely (section 4.8).
  • Stevens-Johnson syndrome - reported very rarely (section 4.8).
  • Hypersensitivity and angioedema, including facial oedema (section 4.8).
  • Irritation or sensitisation - 'If irritation or sensitisation develops, treatment should be discontinued' (section 4.8).
  • Possibly delayed allergic reactions attributable to the methyl and propyl parahydroxybenzoate excipients (section 4.4).

Monitoring

  • Clinical response (section 4.2): 'If signs and symptoms worsen or persist (beyond 14 days of treatment), the patient should be reevaluated, and alternate therapy considered.'
  • Duration (section 4.2): continue the regimen for at least 48 hours after symptoms have disappeared before stopping.
  • Local tolerance (section 4.8): watch for irritation or sensitisation and discontinue treatment if it develops.
  • No laboratory monitoring of any kind is specified in the fetched sections of this SPC.

Clinical monograph

How it works

It binds ergosterol in the fungal cell membrane, forming pores that increase permeability and cause leakage of intracellular contents, giving fungicidal activity chiefly against Candida species.

Prescribing in practice

  • It is essentially not absorbed from the gut, so it acts only on local mucosal or luminal Candida and is ineffective for systemic or deep candidal infection.
  • For oral candidiasis the suspension should be retained in the mouth in contact with the affected areas before swallowing to maximise local effect.
  • Continue treatment for the recommended period after lesions clear to reduce relapse, and consider treating predisposing factors such as poor denture hygiene.

Monitoring

Routine laboratory monitoring is not required; assess clinical response and consider further investigation if oral or gastrointestinal candidiasis fails to resolve.

Counselling the patient

  • Hold the suspension in your mouth, swishing it around the affected areas, before swallowing.
  • Keep using it for a few days after the soreness or white patches have gone.
  • If you wear dentures, clean them well and leave them out overnight to help clear the infection.

Evidence & guidelines

Topical and oral nystatin is a long-established standard treatment for localised mucocutaneous candidiasis.

Reference: NICE CKS; 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).

Related

Curated clinical cross-links plus same-class fallbacks.

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