What is the major toxicity concern with conventional amphotericin B?

• A. Nephrotoxicity
• B. Hepatotoxicity
• C. Ototoxicity
• D. Neutropenia

Answer: (A)

Nephrotoxicity is the major toxicity associated with conventional amphotericin B. While the drug disrupts fungal cell membranes by binding ergosterol, it can also interact with cholesterol in human cell membranes, and the kidneys are especially exposed during IV administration. This leads to afferent arteriolar vasoconstriction and direct tubular injury, causing a drop in GFR and electrolyte wasting (notably potassium and magnesium). Because of this kidney toxicity, amphotericin B has historically limited use, though lipid formulations reduce, but do not completely eliminate, this risk. Other toxicities like ototoxicity, hepatotoxicity, or neutropenia can occur but are less characteristic of the conventional form.