Fungal Infections


Nystatin (Nystin, Mycostatin and multiple other names) is a polyene antifungal originally isolated from Streptomyces noursei in 1950 by Elizabeth Lee Hazen and Rachel Fuller Brown. It was named after the laboratories in which they worked in 1954 - New York State Department of Health. Streptomyces noursei is a soil organism isolated from a farm (owned by William Nourse). It was first used in patients and licensed for use in the 1950’s. It was patented in 1957 and all royalties donated to research. Like all polyenes, it binds to ergosterol in the fungal cell membrane, leading to potassium loss and fungal cell death.

Dose & Delivery

Nystatin is only used topically and dosing is described in units. For vaginal candidiasis, pessaries of 100mg are give daily for 6 days, 200mg for 3 days and 500mg as a single dose. Alternatively 1%, 2% or 10% vaginal cream delivering roughly the same doses as pessaries, may be used, for the same durations. Nystatin cream is also used to treat penile candidiasis (balanitis).

Nystatin 10mg lozenges or troches are used to treat oral candidiasis. They are taken 5 times daily for 14 days for treatment, or 3 times daily for prevention of oral candidiasis.

Most topical skin preparations are 1% cream, lotion or spray, which should be applied 2 or 3 times daily for 2-4 weeks. Nystatin is effective for seborrheic dermatitis, nappy rash due to Candida, some cases of ringworm, tinea cruris and athlete’s foot. A 1% solution can be used for otitis externa. For inflammatory conditions such as seborrheic dermatitis, combined preparations with topical corticosteroid are helpful.

Fungi - the drug is active against        

Nystatin is active against most Candida spp. as well as Cryptococcus neoformans, Aspergillus spp., Histoplasma capsulatum, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Sporothrix schenckii. Nystatin has also been used to treat other fungal problems as Dutch Elm disease and to restore water-damaged mouldy artwork.

Some nystatin resistance is documented in Candida albicans, especially among oral isolates in patients with AIDS treated with Nystatin. Typical rates of resistance, in Candida albicans in a general hospital are 3-6%.

Metabolism distribution and excretion                 

Nystatin is practically insoluble in water. Applied on the skin it penetrates on the surface layer (epidermis), with no systemic absorption. Between 3-10% is absorbed systemically after vaginal administration. Nystatin is metabolised by the liver.

Drug/ Drug interactions                      

There are very few drug/drug interactions with Nystatin. Pessaries of clotimazole may damage latex condoms or diaphragms, and additional contraceptive measures are wise. View drug interaction database.

Side effects                 

Nystatin is generally well tolerated but nausea, vomiting, unpleasant mouth and pruritus (itching) have been reported with oral lozenges. Local skin irritation and a burning sensation are reported after use on the skin. Nystatin may be given in pregnancy.

Structure of nystatin

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