Chapter 22: Anti-Fungal Medications

Polyene antifungals such as Amphotericin B represent a foundational class that disrupts fungal cell membrane integrity by binding to ergosterol, making them highly effective against serious systemic mycoses despite their significant nephrotoxic side effects that limit their use. Nystatin, though similarly structured, exhibits prohibitive toxicity for systemic administration and remains restricted to topical and oral formulations for managing localized Candida infections of the skin and mucosal surfaces. The azole class—encompassing Ketoconazole, Fluconazole, Itraconazole, Voriconazole, Posaconazole, and Isavuconazole—represents a broader therapeutic category that inhibits ergosterol synthesis within the fungal cell membrane, offering improved safety profiles and diverse routes of administration suited to various infection sites. In contrast, the echinocandins function as glucan synthesis inhibitors, targeting the structural integrity of the fungal cell wall rather than the membrane, providing an alternative mechanism for managing resistant infections. For dermatophytic conditions affecting integumentary structures, the chapter discusses Griseofulvin and its disruption of fungal microtubule assembly, alongside Terbinafine and emerging agents that address superficial and nail infections. Additional therapeutic agents such as Flucytosine are presented in the context of combination regimens to enhance efficacy and reduce resistance development, while specialized treatments like potassium iodide are highlighted for specific indications such as sporotrichosis. The chapter synthesizes this pharmacological diversity into a practical framework for clinicians to match therapeutic selection with infection location, causative organism, and individual patient risk factors regarding adverse effects and drug interactions.