Nystatin (Nystan): oral thrush liquid and antifungal cream

Nystatin is an antifungal that, according to the NHS, makes holes in the cell membrane of the fungus so its contents leak out. It is prescribed for oral thrush, for fungal skin infections and to prevent infection in people at risk.

The liquid suspension is for the mouth, and creams and ointments are for the skin; some are combined with steroids, antiseptics or antibacterials, under names such as Trimovate, Timodine and Nystaform. The primary brand is Nystan.

Shake the bottle well, measure with an oral syringe, medicine spoon or dropper (not a kitchen teaspoon), and swill the liquid around your mouth for at least 30 seconds before swallowing. Take it after meals, without mixing it with food or drink, and do not eat or drink for 30 minutes afterwards.

For treatment the NHS gives 1 ml four times a day with at least 3 hours between doses, and for prevention 1 ml once or twice a day. Treatment lasts about a week, plus 2 further days after symptoms have cleared. The liquid begins to work after roughly 2 days.

• If a missed dose is less than 3 hours from the next, skip it. Never double up.

• Nystatin is very safe in overdose, but check with a pharmacist or doctor if you are worried.

Creams and ointments are applied 2 or 3 times a day, usually for 7 to 14 days depending on the condition. Wash your hands afterwards and keep treated skin away from a baby.

If a rash, itching, dryness or swelling develops where you applied it, or a new infection appears, stop and ask a doctor or pharmacist.

The NHS says most adults and children, including babies, can use nystatin liquid, cream or ointment. Tell the prescriber about earlier allergic reactions to nystatin or to anything in the cream or ointment.

The liquid contains sucrose, so mention any problem digesting sugars. Cream or ointment may not suit skin affected by tuberculosis.

The common effects are diarrhoea, nausea and vomiting. Drink water or squash for diarrhoea and take the liquid after eating if you feel sick. Severe diarrhoea for more than 24 hours may stop the combined or progestogen-only pill protecting you.

A serious allergic reaction is rare: call 999 for sudden swelling of the lips, mouth, throat or tongue, very fast breathing or struggling to breathe, throat tightness, confusion, fainting or a swollen itchy rash.

The NHS says you can use nystatin while pregnant or trying for a baby, and that it is safe while breastfeeding, having been used for many years without side effects in breastfed babies. If you treat breast thrush, wash it off before feeding. There is no link with reduced fertility.

Nystatin liquid, cream and ointment are generally fine alongside other medicines, including painkillers; combination products should be checked with a pharmacist. If it has not worked within a week, speak to your doctor. Alternatives include miconazole and fluconazole for oral thrush, and clotrimazole, miconazole and ketoconazole for skin infections.