5/05 PHARM Antifungals Flashcards
* are drugs that weren't mentioned in the SBM, but should know for boards ** are best ones to know of the ones listed
difference btwn yeast, mold, and dimorphic fungi in terms of cellularity?
Yeast = Unicellular Mold = Multicellular Dimorphic = Yeast at BT, Mold at RT
examples of Dimorphic fungi?
Histoplasma, Blastomyces, Coccidioides (indigenous to specific areas and pt populations - ex: HIV)
How can you tell on a plate if it is growing yeast or mold?
yeast: Pasty colonies (resembles bacteria)
mold: Surface texture: Cottony/ woolly/ velvety/ granular…
Are cell membranes present in mammals? fungi?
cell wall: present only in fungi
cell membrane: present in both, but comprised of different compositions
What is the basic composition and function of the cell wall? is it antigenic or non-antigenic?
polysaccharide, proteins, and glycoproteins
fxn: shape, rigidity, strength and protection from osmotic shock
ANTIGENIC
What is the basic composition and function of the cell membrane? is it antigenic or non-antigenic?
phospholipids, sterols
fxn: Protects cytoplasm, Rregulates intake/secretion of solutes, facilitates capsule and cell wall synthesis
didn’t say whether it’s antigenc or not, but personally, I don’t think it’s antigenic??
How does the cell membrane composition differ btwn fungi and mammals?
Present – contains ergosterol
Present – contains cholesterol
knowing the compositional differences btwn the cell wall and cell membrane, what drugs can you use to target each one?
cell wall: Enchinocandins – glycan synthesis inhibitor
cell membrane: Azoles or polyenes to inhibit cell membrane synthesis
- Terbinafine MoA? Indications? Side effect?
MoA: blocks squalene epoxidase to prevent lansterol synthesis (for cell membrane)
Indication: Onychomycosis
GI upset, HA, hepatotoxicity, taste disturbance
name some ergosterol synthesis inhibitors
fluconazole
itraconazole
voriconazole
posconazole*
mechanism of “azoles”?
inhibits ergosterol synthesis by inhibiting the cytochrome p450 enzyme (14-a-demethylase) that converts lanosterol -> ergosterol (for cell membrane)
of all the azoles that we learned, which one has the poorest GI absorption/CNS penetration?
itraconazole
of all the azoles that we learned, which one has the least drug interactions?
fluconazole
indications for fluconazole?
suppression of
- cryptococcal neoforman meningitis in AIDs**
- candida albicans infections in all drug of choice
indication for itraconazole?
histoplasma **
blastomyces
coccidioides
indication for voriconazole?
aspergillus**
prophylaxis during neutropenia and gvhd