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