All of the following antifungal agents act by altering cell membrane permeability, except(2018)
**Core Concept**
The question is testing the student's knowledge of antifungal agents and their mechanisms of action, specifically how they alter cell membrane permeability to exert their antifungal effects.
**Why the Correct Answer is Right**
Amphotericin B acts by binding to ergosterol in the fungal cell membrane, creating pores and increasing cell membrane permeability, which ultimately leads to cell death. This mechanism is crucial in the treatment of serious fungal infections.
**Why Each Wrong Option is Incorrect**
**Option A:** Griseofulvin, a polyene antifungal, actually works by inhibiting fungal microtubule function, not by altering cell membrane permeability. This makes it a correct distractor.
**Option B:** Nystatin, another polyene antifungal, also acts by binding to ergosterol in the fungal cell membrane, creating pores and increasing cell membrane permeability, similar to Amphotericin B. This makes it an incorrect distractor.
**Option C:** Fluconazole, an azole antifungal, acts by inhibiting lanosterol 14α-demethylase, an enzyme involved in ergosterol synthesis, which indirectly affects cell membrane permeability. However, it does not directly alter cell membrane permeability like Amphotericin B does.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that antifungal agents can be categorized based on their mechanisms of action, such as altering cell membrane permeability (polyenes), inhibiting ergosterol synthesis (azoles), or interfering with fungal cell wall synthesis (echinocandins).
**Correct Answer: A. Griseofulvin**