Nystatin, USP
For Extemporaneous Preparation of Oral Suspension

Nystatin USP is an antifungal antibiotic obtained from Streptomyces noursei. It is known to be a mixture, but the composition has not been completely elucidated. Nystatin A is closely related to amphotericin B. Each is a macrocyclic lactone containing a ketal ring, an all-trans polyene system, and a mycosamine (3-amino-3-deoxy-rhamnose) moiety. Nystatin A has a molecular formula of C₄₇H₇₅NO₁₇ and a molecular weight of 926.11.

Nystatin USP is a ready-to-use, non-sterile powder for oral administration which contains no excipients or preservatives. It is available in containers of 50 million, 150 million, 500 million, and 2 billion units. Each mg contains a minimum of 5,000 units.

Nystatin probably acts by binding to sterols in the cell membrane of the fungus with a resultant change in membrane permeability allowing leakage of intracellular components. It is absorbed very sparingly following oral administration, with no detectable blood levels when given in the recommended doses. Most of the orally administered nystatin is passed unchanged in the stool.

For the treatment of intestinal and oral cavity infections caused by Candida (Monilia) albicans.

Hypersensitivity to the drug.

Large oral doses of nystatin have occasionally produced diarrhea, gastrointestinal distress, and possible irritation of the stomach that may result in nausea and vomiting.

Nystatin USP is supplied in containers of 50 million, 150 million, 500 million, and 2 billion units.