Antifungal agents

The four main classes of antifungal drugs are the polyenes, azoles, allylamines and echinocandins. Clinically useful older agents include topical azole formulations (for superficial yeast and dermatophyte infections), first-generation triazoles (fluconazole and itraconazole, for a range of superficial and invasive fungal infections), amphotericin B formulations (for a broad range of invasive fungal infections) and terbinafine (for dermatophyte infections). Clinically important newer agents include members of the echinocandin class (eg, caspofungin) and second-generation triazoles (eg, voriconazole and posaconazole). Voriconazole and posaconazole have broad-spectrum activity against yeasts and moulds, including Aspergillus species. Posaconazole is the only azole drug with activity against zygomycete fungi. Caspofungin and the other echinocandins are effective in treating Candida and Aspergillus infections. The azoles are relatively safe, but clinicians should be aware of drug-drug interactions and adverse effects, including visual disturbances (with voriconazole), elevations in liver transaminase levels, and skin rashes. Caspofungin has minimal adverse effects. Combination antifungal therapy may be appropriate in selected patients with invasive fungal infections, but is empiric and driven by individual physician practice.