Classification of Antifungal Agents

Classification of Antifungal Agents

• Polyenes:
  • Bind to ergosterol in fungal cell membranes, creating pores and disrupting membrane function
  • Examples: Amphotericin B, Nystatin
• Azoles:
  • Inhibit lanosterol 14α-demethylase, blocking ergosterol synthesis
  • Examples: Fluconazole, Itraconazole, Voriconazole
• Allylamines:
  • Inhibit squalene epoxidase, blocking ergosterol synthesis
  • Examples: Terbinafine
• Echinocandins:
  • Inhibit β-(1,3)-glucan synthase, blocking fungal cell wall synthesis
  • Examples: Caspofungin, Micafungin, Anidulafungin
• Fluoropyrimidines:
  • Inhibit thymidylate synthase, blocking DNA synthesis
  • Examples: Flucytosine

Mechanisms of Action

• Fungal cell membrane disruption:
  • Polyenes and Azoles disrupt fungal cell membranes, leading to cell death
• Inhibition of ergosterol synthesis:
  • Azoles, Allylamines, and Fluoropyrimidines inhibit ergosterol synthesis, disrupting fungal cell membrane function
• Inhibition of fungal cell wall synthesis:
  • Echinocandins inhibit β-(1,3)-glucan synthase, blocking fungal cell wall synthesis

Spectrum of Activity

• Broad-spectrum antifungals:
  • Effective against a wide range of fungi, including Candida, Aspergillus, and Histoplasma
  • Examples: Amphotericin B, Voriconazole
• Narrow-spectrum antifungals:
  • Effective against specific types of fungi, such as dermatophytes
  • Examples: Terbinafine

Adverse Effects and Interactions

• Common adverse effects:
  • Nausea, vomiting, diarrhea, headache
• Severe adverse effects:
  • Hepatotoxicity, nephrotoxicity, allergic reactions
• Interactions:
  • CYP450 inhibitors or inducers may affect antifungal pharmacokinetics
  • Antifungals may interact with other medications, such as warfarin and statins

Classification of Antifungal Agents

• Polyenes bind to ergosterol in fungal cell membranes, creating pores and disrupting membrane function, with examples including Amphotericin B and Nystatin.
• Azoles inhibit lanosterol 14α-demethylase, blocking ergosterol synthesis, and include Fluconazole, Itraconazole, and Voriconazole.
• Allylamines inhibit squalene epoxidase, blocking ergosterol synthesis, with Terbinafine as an example.
• Echinocandins inhibit β-(1,3)-glucan synthase, blocking fungal cell wall synthesis, including Caspofungin, Micafungin, and Anidulafungin.
• Fluoropyrimidines inhibit thymidylate synthase, blocking DNA synthesis, with Flucytosine as an example.

Mechanisms of Action

• Polyenes and Azoles disrupt fungal cell membranes, leading to cell death through fungal cell membrane disruption.
• Azoles, Allylamines, and Fluoropyrimidines inhibit ergosterol synthesis, disrupting fungal cell membrane function.
• Echinocandins inhibit β-(1,3)-glucan synthase, blocking fungal cell wall synthesis.

Spectrum of Activity

• Broad-spectrum antifungals, including Amphotericin B and Voriconazole, are effective against a wide range of fungi, such as Candida, Aspergillus, and Histoplasma.
• Narrow-spectrum antifungals, such as Terbinafine, are effective against specific types of fungi, like dermatophytes.

Adverse Effects and Interactions

• Common adverse effects of antifungal agents include nausea, vomiting, diarrhea, and headache.
• Severe adverse effects include hepatotoxicity, nephrotoxicity, and allergic reactions.
• Interactions with antifungal agents can occur with CYP450 inhibitors or inducers, affecting pharmacokinetics, and with other medications, such as warfarin and statins.

Learn about the different types of antifungal agents, including polyenes, azoles, allylamines, and echinocandins, and how they work to combat fungal infections.