Why are many antifungal drugs very toxic?

Many antifungal drugs are toxic because they target processes or components that are similar in both fungal and human cells, leading to potential harm to human tissue. For example, drugs like amphotericin B bind to ergosterol, a key component of fungal cell membranes, but can also affect cholesterol in human cell membranes. Additionally, the narrow therapeutic window of some antifungal agents means that doses effective against fungi can also cause significant toxicity in humans. This dual targeting can result in side effects that range from mild to severe, complicating treatment.