Amphotericin b (fungilin, fungizone, abelcet, ambisome, fungisome, amphocil, amphotec) is a polyene antifungal drug, often used intravenously for systemic fungal infections. Its name originates from the chemicals amphoteric properties. Two amphotericins, amphotericin a and amphotericin b are known, but only b is used clinically, because it is significantly more active in vivo. Amphotericin a is almost identical to amphotericin b (having a double c=c bond between the 27th and 28th carbons), but has little antifungal activity. Currently, the drug is available as plain amphotericin b, as a cholesteryl sulfate complex (abcd), as a lipid complex (ablc), and as a liposomal formulation (lamb). The latter formulations have been developed to improve tolerability for the patient, but may show considerably different pharmacokinetic characteristics compared to plain amphotericin b.