A Comprehensive Monograph on Nystatin (DB00646)

1.0 Executive Summary

Nystatin is a polyene macrolide antibiotic with a long-standing history in the management of fungal infections. Discovered in 1950 from the soil bacterium Streptomyces noursei, it was the first agent of its class to be used clinically, establishing a new paradigm for antifungal therapy. Its primary mechanism of action involves binding with high affinity to ergosterol, an essential sterol in the fungal cell membrane. This interaction leads to the formation of transmembrane pores, disrupting membrane integrity and causing the leakage of vital intracellular components, which results in either fungistatic or fungicidal activity, particularly against a broad spectrum of yeasts and fungi, most notably Candida species.

The clinical utility and safety profile of Nystatin are fundamentally defined by its pharmacokinetic properties. When administered orally or topically, it undergoes negligible systemic absorption. This characteristic confines its therapeutic effects to the site of application, making it an exceptionally safe and effective treatment for localized cutaneous, mucocutaneous, and gastrointestinal candidiasis, including oropharyngeal thrush, diaper dermatitis, and intestinal infections. Conversely, this same property, combined with significant systemic toxicity when administered parenterally, renders it unsuitable for the treatment of systemic mycoses.

Available in a variety of formulations—including oral suspensions, tablets, topical creams, ointments, and powders—Nystatin allows for targeted local therapy. Despite the advent of newer, systemically active antifungal agents, Nystatin remains a valuable and widely prescribed medication. Its inclusion on the World Health Organization's List of Essential Medicines underscores its enduring importance in global health as a reliable, low-cost, and safe option for the management of common, non-invasive fungal infections.