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25 Cards in this Set

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What drugs would you use for a deep fungal infection?
*Ampho B, Flucytosine, Fluconazole, Itraconazole and Voriconazole
What drugs would you use for a superficial fungal infection?
Nystatin, Ambo B, Terbinafine, Griseofulvin, Miconazole and Ketaconazole
MOA of Amphotericin B
Binds to ergosterol and forms a pore, > permeability to ions in the cell (like K+) resulting in cell death
How do you administer Ampho B?
IV (note: does NOT cross BBB, so must give intrathecally to reach CSF)
Major tox of Ampho B?
Nephrotoxic (reversible)
Amphotericin B, CIDAL or STATIC?
CIDAL in absence of cell growth, STATIC @ a low dose
MOA of Flucytosine
Converted to 5-FU, which inhibits fungal DNA and RNA synthesis by blocking thymidylate synthase and < production of dTMP
When Flucytosine is Rx, what will "build up" in the pathway of its MOA?
dUMP will > as its conversion to dTMP is blocked via the blockage of thymidylate synthase
Why is Flucytosine selective to fungi?
host cells don't take up Flucytosine (i.e. they don't convert Flucytosine to 5FU)
This antifungal is intolerable in AIDS pts
Flucytosine
What drug is often Rx for its synergistic effects with Ampho B?
Flucytosine (< resistance, Ampho B allows more uptake of Flucytosine, a lower dose of Ampho B is required, and Ampho may enhance the tox of Flucytosine by impairing its renal excretion)
Which one penetrates the CNS, Flucytosine or Ampho B?
Flucytosine
MOA of "azoles"
Blocks ergosterol synthesis by inhibiting sterol 14-alpha-demethylase (cytochrome P450 enzyme) --> depletion of ergosterol and > permeability of cell membrane
Leads to the accumulation of 14-alpha-methyl sterols
azoles
What are some consequences of the MOA of azoles?
When you inhibit cP450 enzymes you can interfere with biosynthesis of adrenal and gonadal steroid hormones--> gynecomastia, infertility and menstrual irregularities
Also- drug interaction potential
Which group of antifungals may < Ampho B's effects and why?
azoles may < Ampho B's effects bc azoles inhibit ergosterol synthesis, < binding of Ampho B
MOA of Nystatin
Binds to ergosterol and forms pore (just like Ampho B)
How do you administer Nystatin?
Topical and possibly oral for GI tract. too "Nasty" to give IV
MOA of Terbinafine?
Inhibits squalene epoxidase
Rx with Terbinafine leads to the accumulation of what?
Squalene, which is toxic to fungi (CIDAL)
MOA of Griseofulvin
Inhibits mitosis of cells by disrupting spindle formation in fungi ...SLOW MOA...(Used to tx Ringworm)
What do you tx p. jiroveci lung infections with?
Trimethoprim & Sulfamethoxazole (Co-Trimoxazole); block folate synthesis
Leads to an accumulation of Lanosterol
Azoles (Block Lanosterol-->Ergosterol by inhibiting Lanosterol 14alpha demethylase)
Impairs pyrimidine metabolism
Flucytosine
Inhibits nuclear divisino
Griseofulvin