How do antifungal drugs differ from antibiotics that target bacteria?

Antifungal drugs and antibiotics differ primarily in their biological targets, which are dictated by the fundamental structural differences between fungal and bacterial cells.

Mechanisms of Action

• Antibiotics: These agents target bacterial processes, such as inhibiting cell wall synthesis (e.g., penicillins), interfering with protein synthesis, or disrupting DNA and RNA replication. Because bacteria are prokaryotic, many antibiotics can selectively target bacterial structures without harming human cells.12
• Antifungal Drugs: Fungi are eukaryotic, sharing more cellular similarities with humans than bacteria do. Consequently, antifungals often target unique fungal components like ergosterol, a steroid found in fungal membranes. Drugs like polyenes bind to ergosterol to create pores in the membrane, while azoles and allylamines block its synthesis.3

Toxicity and Selectivity

Because human cells also contain cholesterol—which is structurally similar to ergosterol—antifungal treatments often carry a higher risk of toxicity compared to many antibiotics. While some antibiotics that target cell membranes can be toxic to humans, most are designed to exploit specific bacterial vulnerabilities.31