Caspofungin Acetate (MK-0991 Acetate) is an antifungal drug, and noncompetitively inhibits 1,3-β-d glucan synthase activity. In Vivo: Mice injected with caspofungin at vitreal concentrations from 0.41 to 4.1 μM do not have significant alterations in their ERG waveforms, and their retinas have no detectable morphologic changes or loss of cells. At the vitreal concentration of 41 μM, caspofungin reduces the amplitudes of the a-waves, b-waves, and scotopic threshold responses of the ERG and also produces a decrease in the number of cells in the ganglion cell layer^[1]. Caspofungin (8 mg/kg) or amphotericin B at 1 mg/kg given i.p. once daily for 7 days beginning at 30 h after infection resulted in 100% survival through day 28 relative to vehicle control treatment, which results in 100% mortality by day 11 after infectious challenge. Caspofungin reduces recovery of viable Candida from kidney and brain tissues compared to vehicle control treatment on day 5, when control burden peaked. Caspofungin-treated mice dosed with 2 mg/kg or greater have significantly lower brain burden than amphotericin-B-treated mice at day 5. Amphotericin B and caspofungin treatment reduce kidney fungal burden by 1.7 log CFU/g and 2.46 to 3.64 log CFU/g, respectively^[2].