Antifungal Drugs Flashcards
What is the fungal equivalent of cholesterol?
Ergosterol
Which class of antifungal medication is fungicidal?
Polyenes. Ex. Nystatin, pimaricin, amphotericin B
What is the target of polyene drugs?
Ergosterol. Binds to it forming holes in the cell membrane
What is the difference between superficial and systemic mycoses?
Superficial- limited to the epidermal region
Systemic- invade the skin, lungs and lymphatic tissue
Which fungus structure is critical for cell viability and pathogenicity?
Cell wall
Allylamine examples
Naftifine, terbinafine, butenafine
Allylamine MOA
Inhibit ergosterol biosynthesis at the level of squalene epoxidase
Azole/triazole examples
Fluconazole, itraconazole, ketoconazole
Azole/triazole MOA
Inhibit cytochrome P450 dependent enzymes (C14-alpha-demthylase) involved in the biosynthesis of ergosterol
Polyene example
Nystatin, pimaricin, amphotericin B
Polyene MOA
Interact with sterols in the cell membrane to form channels through which small molecules leak from the out of the fungal cell
Echinocandin examples
Caspofungin, micafungin, anidulafungin
Echinocandin MOA
Concentration-dependent, noncompetitive inhibitors of β-1,3 glucan synthase, an essential component of the fungal cell wall
5-fluorocytosine MOA
Inhibitor of both DNA and RNA synthesis via the intracytoplasmic conversion of 5-fluorocytosine to 5-fluorouracil.
Polyene structure
Alternating conjugated double bonds that constitute a part of their macrolide ring structure
Polyenes have ____ times binding affinity for ergosterol over cholesterol
500 times
First broad spectrum antifungal
Nystatin
True or false: Natamycin is absorbed systemically
False
Which polyene is available in IV formulation?
Amphotericin B
Difference between conventional and liposomal formulation of amphotericin B?
Liposomal formulation less nephrotoxic
Amphotericin B adverse effects
Nephrotoxicity, hypokalemia, hypomagnesemia, bone marrow suppression
Which antifungal was synthesized as a potential serotonin reuptake inhibitor?
Naftifine
Where does terbinafine accumulate?
Nails
Azole structure
5-membered nitrogen heterocyclic ring compound containing at least one other non-carbon atom (nitrogen, sulfur, or oxygen)
Which agent may be used for neonatal thrush?
Miconazole
Which agent is considered the treatment of choice for aspergillus?
Voriconazole
Difference between isoconazole and miconazole?
Chlorine substitution pattern
Which CYP enzymes does fluconazole inhibit?
CYP2C9 and CYP3A4
Voriconazole adverse effects
Hepatotoxicity, visual disturbances (common), hallucinations, QTC prolongation and dermatologic reactions
True or false: Caspofungin is not viable as an oral drug and must be administered intravenously
True
