Pathogenic and opportunistic fungi can cause widespread infections (mycoses1). A selection of an antifungal agent is usually based on their spectrum of activity and causative pathogen implicated in infection. Pharmacokinetic and toxicity also play an important role in the selection of drugs.
I • Antifungal agents used in pathogenic fungi infections
= Systemic (deep) mycoses (coccidioidomycosis, paracoccidioidomycosis, histoplasmosis, cryptococcosis, blastomycosis)
□ Antibiotics - amphotericin B, Mykoseptin
□ Triazole derivatives - itraconazole, fluconazole
□ Imidazole derivatives - ketoconazole
= Epidermomycosis (dermatomycosis)
□ Antibiotics - griseofulvin
□ Allylamines - terbinafine (lamisil, terbisil)
□ Triazole derivatives - itraconazole, fluconazole
□ Imidazole derivatives - ketoconazole, clotrimazole, miconazole
□ Nitrophenol derivatives - nitrofungin
□ Iodine compounds - potassium iodide, alcoholic solution of iodine
II • Agents, used in opportunistic fungi infections (for example, candidiasis)
□ Antibiotics - nystatin, levorin, amphotericin B
□ Triazole derivatives - fluconazole, itraconazole
□ Imidazole derivatives - miconazole, clotrimazole, ketoconazole
□ Bis-quaternary ammonium salts derivatives - dequalinium (decaminum)
Antifungal agents can also be classified based on the mechanism of their action (Fig. 31.1).
• Agents, impairing structure and function of the fungi cytoplasmic membrane
= Ergosterol (ergosterine) synthesis inhibitors
□ Triazole derivatives - itraconazole, fluconazole
Fig. 31.1. Main mechanisms of action of several antifungal agents
□ Imidazole derivatives - ketoconazole, miconazole, clotrimazole
□ Allylamines - terbinafine
= Compounds that bind to ergosterol and form pores in cytoplasmic membrane