New drugs will soon be incorporated into the echinocandin class of antifungals. The first to be released on to the market will be anidulafungin. The pharmacokinetic characteristics of this drug clearly distinguish it from the only representative of this family of antifungal agents available to date: caspofungin. Specifically, this new drug has a greater volume of distribution, a higher elimination half-life and, moreover, an elimination system -- spontaneous degradation --, thus avoiding interactions with other drugs and allowing its use without dosage adjustments in patients with renal or liver impairment. These are the main pharmacological differences between anidulafungin and caspofungin, since the latter requires dosage adjustments in patients with hepatic insufficiency, in patients under treatment with inducers of cytochrome P450 activity and in obese patients. Moreover, plasma concentration monitoring is recommended in patients requiring caspofungin who are also under treatment with cyclosporin A or tacrolimus. Clinical experience suggests that there are few differences in the tolerability profiles of the two drugs, both of which are excellent.