Echinocandins: Pharmacokinetic and Therapeutic Issues

Invasive infections caused by Candida species are a major concern today due to increasing numbers of at-risk patients and high rates of mortality, as well as increased length of hospital stays and healthcare costs associated with these infections. An additional concern is the current trend towards greater numbers of infections caused by species or strains that are resistant to traditional antifungal agents, such as fluconazole or other triazoles. Echinocandins are the newest class of antifungals. They have a unique mechanism of action, and exhibit activity against a broad range of Candida species and strains, including those resistant to azoles or polyenes. Few studies have directly compared the three approved echinocandins (caspofungin, micafungin, and anidulafungin) for efficacy, but the existing data have not suggested major differences to date. All the echinocandins possess excellent tolerability and safety, and although there are some pharmacokinetic differences, they are relatively small and generally do not influence drug selection. Consequently, echinocandins are now considered by most experts to be the first-line treatment of invasive candidiasis in critically ill patients. Caspofungin was the first approved member of the class; it has the most available data and the most indications of the echinocandins.