26 - Antifungal drugs Flashcards
MOA of polyene antifungals
binds to ergosterol in fungal cell membranes, forming artificial pores
MOA of azoles
inhibit CYP 450 enzymes, blocking the synthesisof ergosterol
toxicity of systemic Ketoconazole:
interferes with steroid hormone synthesis; hepatotoxic
azole antifungal with good CNS penetration:
fluconazole
The azole antifungal with the broadest spectrum
Posaconazole
Azoles used in superficial skin fungal infections:
Clotrimazole, Ketoconazole, Miconazole
Polyene antifungal used in systemic fungal infections:
Amphotericin B
Treatment of sporotrichosis:
itraconazole, or potassium iodide
DOC for meningitic fungal infections:
fluconazole
DOC for cryptococcal encephalitis:
amphotericin B + flucytosine
Mechanism of action of flucytosine:
- Accumulate in fungal cells through permease
- Converted to 5-FU by cytosine deaminase
- 5-FU inhibits thymidilate synthase
How does flucytosine selectively act on fungal cells?
Low amount of permease and cytosine deaminase in the human body
DOC in aspergillosis:
Amphotericin B
DOC for Pneumocystis jiroveci pneumonia:
Trimethoprim-sulfamethoxazole
- Drug class of caspofungin
- MOA of caspofungin
- echinocandin
- inhibits Beta-glucan synthase decreasing fungal cell wall synthesis
This drug is used as salvage therapy for invasive aspergillosis:
Caspofungin
MOA of griseofulvin:
interferes with microtubule functioning
- Drug class of terbinafine
- MOA of terbinafine
- allylamine
- inhibits fungal squalene oxidase, interfering with ergosterol synthesis
DOC for onychomycosis
Terbinafine
- Drug class of Nystatin
- MOA of nystatin
- uses of nystatin (3)
- Polyene antifungal
- binds to ergosterol in fungal cell membrane, creating pores
- Candidiasis (oropharyngeal, esophageal, vaginal)
