Fungal Chemotherapy Flashcards
Molds form threadlike filaments called…
hyphae
If asexual budding results in an attached, what is the resulting structure called?
Pseudohyphae
A mass of hyphae is called…
mycelium
Fungi that exist in both yeast and mold form are called
dimorphic
Hyphae on parasitic fungi are referred to as…
Haustoria
Spores result from what kind of reproduction?
sexual
Conidia result from what kind of reproduction?
assexual
What is the fungicidal function of Amphrotericin B?
“Tears” holes into the cell wall by binding to ergosterol
Why is amphotericin B largely toxic?
It also binds cholesterol
Is amphotericin B used for systemic or topical fungal infections?
systemic
What two types of antifungals prevent ergosterol synthesis?
“Onazoles” and Terbinafine
Why do the “onazoles” not work with the brain?
Efflux pumps in brain
Are the onazoles fungistatic or fungicidal?
static
What human toxicity is seen in the onazoles? (four things)
Hepatotoxicity
neurotoxicity
interferes with hormone synthesis (don’t use in pregnancy)
drug drug interactions
Is terbinafine fungicidal or fungistatic?
Cidal
Which enzyme do the onazoles bind to in the ergosterol synthesis pathway?
Erg11 (p450)
How does terbinafine work?
Binds to squalene epoxidase, leading to a toxic amount of squaline
Terbinafine toxicity?
Use topically because interference with CYP2D6
Flucytosine is an analogue of _____ and subsequently interferes with ___ and ___ _______.
5 fluorouracil, DNA and RNA synthesis
Why is flucytosine a good antifungal choice for menningitis?
crosses blood brain barrier
What is the antifungal mechanism of griseofulvin?
Binds to microtubules and prevents spindle formation in fungi
Why does griseofulvin concentrate in the dead skin layers?
It’s lipophilic
How is griseofulvin toxic?
Teratogenic
How does caspofungin work?
blocks synthesis of beta-d-glucan polysaccharide
Can caspofungin treat meningitis?
No. Cannot cross BBB.
