Nystatin !

Polyene antifungal that is not absorbed from the gut or skin. Used as an oral liquid or cream for thrush and Candida infections of the skin.

Updated 2026-11-01

Class: Polyene antifungals
Target: Ergosterol in the fungal cell membrane (a sterol, not a protein)
ATC code: A07AA02
WHO Model List of Essential Medicines

Mechanism of action

Nystatin binds sterols in the membrane of Candida and changes its permeability, so cell contents leak out. It is fungistatic and fungicidal against yeasts and has no useful activity against bacteria, protozoa or viruses. Because it is barely absorbed, it acts only where it is applied and is not used for systemic mycoses.

Nystatin binds sterols in the Candida membrane
The membrane becomes leaky and cell contents escape
The yeast dies where the drug touches it

Pharmacokinetics

Absorption: Negligible from the gut, skin or vagina.
Elimination: Most of an oral dose leaves unchanged in the stool; in kidney failure, plasma levels can occasionally be measurable.

Indications

Oral candidiasis (thrush). Candidiasis: oral, oesophageal and invasive →
Cutaneous and mucocutaneous Candida infections (cream, ointment or powder). Cutaneous and mucocutaneous candidiasis →

Adverse effects

Common

Mouth irritation
Nausea, vomiting or diarrhoea, mainly with large oral amounts
Local irritation with skin forms

Contraindications

Hypersensitivity to any component
Not used to treat systemic mycoses

Key interactions

Other medicines: No clinically relevant interactions are described in its label; it is barely absorbed.

What is monitored

Clinical response of the mouth or skin lesions
Signs of irritation or allergy

Administration and safety

Oral suspension: half of each dose is placed on each side of the mouth and held there as long as possible before swallowing.
In infants, use the dropper to place half on each side of the mouth and avoid feeding for a few minutes afterwards.
Cream, ointment and powder are for the skin only: keep them out of the eyes, mouth and vagina.

Nursing care

Inspect the mouth (white plaques, redness) before and during treatment.
Teach the swish-and-hold technique and to complete the course even if plaques fade.
Stop and report if irritation or a rash appears.

Pregnancy and breastfeeding

No animal or human studies exist; it is used in pregnancy only if clearly needed, and very little reaches the blood.

Test yourself

Think of the answer, then tap the question to see it.

Why can nystatin be swallowed without systemic toxicity?

It is practically not absorbed from the gut; almost all of it leaves unchanged in the stool.

How is nystatin suspension given for oral thrush?

Half of the dose on each side of the mouth, held as long as possible before swallowing, so the drug stays in contact with the lesions.

To which drug is nystatin chemically related?

Amphotericin B: both are polyenes that bind membrane sterols.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - NYSTATIN ORAL SUSPENSION- nystatin suspension (DailyMed (U.S. National Library of Medicine), 2026); Nystatin: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); Nystatin Topical: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2018); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 61 (McGraw Hill, 2023).

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Representative model, for educational purposes only.