Nystatin

Nystatin (Nystan®, Infestat®, Nystamont®) is an polyene antimycotic drug reserved for topical use due to its toxicity. Candida spp. are sensitive to nystatin.

Uses

Cutaneous, vaginal, mucosal and esophageal Candida infections can be treated with nystatin. Cryptococcus is also sensitive to nystatin.

Nystatin is often used as prophylaxis in patients who are at risk for fungal infections, such as AIDS patients with a low CD4⁺ count and patients receiving chemotherapy.

It is prescribed in units, with doses varying from 100,000 (for oral infections) to 1 million (for intestinal ones). As it is not absorbed from the gut, it is safe for oral use.

Method of action

Like, amphotericin B and natamycin, nystatin binds to ergosterol, the main component of the fungal cell membrane. When present in sufficient concentrations, it forms a pore in the membrane that leads to K⁺ leakage and death of the fungus. As mammals do not have ergosterol-based cell membranes, the drug only affects fungi.

Origin

Like many other antimycotics and antibiotics, nystatin is itself a fungal product. It was isolated from Streptomyces noursei in 1950 by Elizabeth Lee Haxen and Rachel Fuller Brown, who were doing research for the Division of Laboratories and Research of the New York State Department of Health. The soil sample where they discovered nystatin, was from the garden of Hazen's friends called Nourses, therefore the strain was called noursei. Hazen and Brown named nystatin after the New York State Public Health Department.