Pharmacology - Antifungals 2

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Pharmacology - Antifungals 2
2014-01-29 17:10:36
Pharmacology Antifungals
Pharmacology - Antifungals 2
Pharmacology - Antifungals 2
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  1. How can nephrotoxicity by Amphotericin B be reduced?
    Na loading
  2. Why does Amphotericin B cause Hypochromic normocyctic anemia?
    Decrease in erythropoietin, so less blood cells produced
  3. Overall, would you consider Amphotericin B a drug that is fairly safe/ has low adverse effects?
    No, has many side effects
  4. How can you reduce infusion related side effects of Amphotericin B?
    Pretreat with corticosteroids or Antihistamines
  5. Lipid dispersion of Amphotericin B, like amphotec (ABCD) work by what mechanism?
    The drug has a higher affinity for ergosterol over the lipid formulation ( drug also has a greater affinity for the lipid formulation than cholesterol)
  6. What is the MOA for Nystatin?
    Binds to ergosterol in membrane and increases permeability to K and Mg to leak out ( creates pores)
  7. Can Nystatin be given systemically?
    No, too toxic
  8. What are the route of administrations available for Nystatin?
    Oral, Vaginal, Mouthwash and Topical
  9. Is Nystatin well absorbed orally?
    No, not absorbed, but given orally for GI infecations
  10. What are the indications for Nystatin?
    Fungal infection of the intestines and oral mucosa, esophageal candida and dermatophyte infections
  11. What are the adverse effects of Nystatin?
    Nausea/diarrhea for oral, stinging topically
  12. What groups of patients might most commonly need to use the oral Nystatin mouth washes?
    Immunocomprimised/chemo patients, AIDS
  13. Flucytosine is a derivative of what?
    5-flourouracil, and anticancer drug that inhibits DNA synthesis
  14. Why is Flucytosine not active against cancer?
    It can’t permeate mammalian cells
  15. Why can Flucytosine permeate fungal cells but not mammalian cells?
    Because fungal cells have an enzyme called permease that transfers it
  16. What is the MOA of Flucytosine?
    Inhibits DNA and RNA synthesis by inhibiting thymidylate synthesis and activating phosphoribosyl transferase
  17. Is Flucytosine fungistatic of fungicidal?
  18. Describe the treatment plan required to treat a meningeal infection with Flucytosine?
    Use in combo with Amphotericin B
  19. Does Flucytosine cross the BBB?
  20. Flucytosine should be used with Amphotericin B for synergistic effects when treating meningeal infections, what other reason, might you use this combination?
    To reduce development of resistance
  21. Does resistance develop quickly or slowly to Flucytosine?
  22. Would you use flucytosine for a candida infection?
    Can be used, but probably not, because there are better drugs
  23. What are the main clinical uses for Flucyosine?
    Systemic or Meingeal Cryptococcus and Chromoblastomycosis
  24. To treat chromoblastomycosis with flucytosine, what drug would you give it in combination with?
  25. How is Flucytosine administered?
  26. Is Flucytosine well absorbed orally?
  27. What tissues does Flucytosine distribute to?
    Most, including the CNS
  28. How is Flucytosine eliminated?
  29. Why does Flucytosine effect some mammalian cells like an anti-cancer drug, causing effects like stomach epithelial cells and bone marrow supression?
    Fungus converts it to 5-flourouracil and some of that leaks out and is absorbed by the human cells