antifungal text file.txt

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  1. What is the broadest spectrum antifungal?
    Amphotericin B
  2. What is its mechanism of action?
    Interacts c ergosterol to create membrane channels that cause loss of intracellular components
  3. What is the mechanism of resistance?
    Organisms c less ergosterol in their membranes
  4. How is it administered?
    Give IV for systemic infections
  5. What is its distribution?
    • Large volume of distribution --> not removed by dialysis
    • Board Q: Don't need to redose ampho after kidney dialysis (need to redose aminoglycosides)
    • Poor CNS penetration
  6. What is its major toxicity?
    Highly nephrotoxic
  7. What minor side effects can be seen c ampho injection?
    Chills and fever
  8. What can be given to reduce these effects?
    Meperidine__opioid analgesic
  9. In what cases is amphotericin B NOT the DOC?
  10. Systemic aspergillosis --> voriconazole
  11. Reminder: Aspergillus = septate hyphae, branching @ acute angles, immunosuppressed
  12. Cryptococcus --> amphotericin + flucytosine
  13. How long is Tx given?
    From 6 wks to 3 or 4 months
  14. What is the mechanism of flucytosine?
    Converted to 5-fluorouracil which inhibits thymidylate synthase and fungal DNA synthesis
  15. What are its pharmacokinetic properties?
    Well absorbed orally, enters CSF (perfect for Cryptococcus)
  16. What are the adverse effects of flucytosine?
    Depression of bone marrow, GI disturbance, hair loss
  17. What is the mechanism of ketoconazole?
    Inhibits fungal lanosine 14 alpha-demethylase to prevent ergosterol synthesis
  18. What is its antifungal spectrum?
    Wide, but still smaller than ampho
  19. What are its pharmacokinetics?
    • Well absorbed after oral administration and bound to albumin
    • Extensively metabolized by liver and partially secreted by kidney (not affected by renal disease)
  20. What causes its major adverse effects?
    • Inhibition of human CYP3A4:
    • Interactions c many Rx: warfarin, phenytoin (NOT digoxin)
    • Inhibition of adrenal and testicular function (due to inhibition of cholesterol synthesis)
    • Gynecomastia (also seen c cimetidine)
  21. How does fluconazole stand out from the other -azoles?
    • Excellent CNS penetration
    • NO interaction c P450
    • No inhibition of testicular and adrenal steroidogenesis
  22. How is it administered?
    IV and oral
  23. What Rx is almost identical to ketoconazole?
  24. What is the DOC for invasive aspergillosis?
  25. What are the adverse effects?
    • Drug interactions like ketoconazole via inhibition of P450
    • Visual impairment
  26. Which class of Rx are fungi unlikely to develop resistance to?
  27. What is the echinocandin MOA?
    Inhibit synthesis of beta (1,3)-D-glucan in the cell wall
  28. What makes them a good Rx choice?
    Lack of nephrotoxicity
  29. What are the echinocandins?
    Caspofungin, micafungin, anidulafungin
  30. How are they administered?
  31. What is caspofungin often used for?
    Invasive aspergillosis in refractory patients
  32. What are the caspofungin adverse effects?
    • ? LFTs, histamine release, HA, chills, GI effects
    • Boards: histamine release also seen in tubocurarine, opioids, vancomycin
  33. What is the MOA of griseofulvin?
    Binds to microtubules and destroys mitotic spindle ? inhibits mitosis (fungistatic)
  34. When is it indicated?
    Dermatophyte infections of skin, hair, and nails
  35. What are its pharmacokinetic properties?
    • Oral or topical application
    • Poor solubility and absorption from GI tract
    • Accumulates in keratin
  36. What are its adverse effects?
    • Disulfiram-like effects [BOOM]
    • Reminder: cefamandole, cefoperazone
    • Contraindicated in acute intermittent porphyria
  37. What is the nystatin MOA?
    Similar to amphotericin B --> binds sterol and lyses cell
  38. When is nystatin often used?
    Candidal infections
  39. How is it administered?
    Orally and topically
  40. What are the pharmacokinetic properties?
    • NOT absorbed from the GI tract
    • Similar to vancomycin and aminoglycosides
    • NOT absorbed from skin or mucous membranes
  41. What is the MOA of terbinafine (Lamisil)?
    Interferes c fungal sterol synthesis
  42. How is it used?
    Oral or topical application for dermatophytes and onychomycoses
  43. What are the pharmacokinetic properties?
    Well abosrbed, widely distributed, accumulates in keratin
  44. What is the worst side effect of terbinafine?
    Hepatic failure
  45. What are the other Rx often used topically?
    • Miconazole nitrate: tinea pedis, vaginal candidiasis
    • Clotrimazole (Lotrimine)
    • Ciclopirox olamine
    • Tolnaftate (Tinactin)
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antifungal text file.txt
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