ID: Echinocandins, griseofulvin, Polyenes, Pyrimidine, Antifungals, Lamisil

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  1. Echinocandins is a class of antifungals that targets:
    fungal cell walls
  2. how do antifungal drugs not affect human cell walls?
    Humans don’t have a cell wall, can target the fungi while minimizing likelihood of toxicities to patient being treated
  3. Echinocandins drugs:
    • Parenteral!!
    • Caspofungin (Cancidas)
    • Anindulafungin
    • (Eraxis)
    • Micafungin (Mycamine)
  4. Echinocanins MOA:
    • Fungal cells have both an outer cell wall and a cell membrane.
    • Cell wall is thought to provide structural rigidity.
    • Chitin & beta-1,3-glucan are responsible for the cell wall’s rigidity.
    • Beta-1,3-glucan is synthesized via beta-1,3-glucan synthase
    • Echincandins inhibit beta-1,3-glucan synthase so the cell wall is not as strong.
    • This leads to cell lysis.
  5. indications for echinocandins:
    • Severe invasive fungal infections: 
    • Candida (fungicidal)·        
    • Aspergillus (fungistatic)
  6. Micafungin (Mycamine) SE:
    • common: diarrhea, N/V, fever, hypokalemia, HA, thrombocytopenia
    • serious: anaphylaxis, hemolytic anemia, hepatotoxicity, renal impairment, sepsis
  7. what is Griseofulvin?
    an antifungal used for dermatophytes
  8. Griseofulvin drugs:
  9. Griseofulvin indication:
    MC fungal species:
    when do you use it?
    • Tinea: dermatophyte infections (Trichophyton, Microsporum & Epidermophyton) of the skin & hair
    • when to use? When topicals don’t work
  10. griseofulvin MOA:
    • Griseofulvin is deposited into keratin precursor cells (increases keratin resistance to fungal infection)
    • Disrupts mitotic spindle
    • Then it is taken up by fungal cells & binds to fungal proteins, including tubulin
    • Tubulin is needed to separate dividing   chromosomes
    • Thus, griseofulvin inhibits cell division in fungi
  11. Grisefulvin kinetics:
    • Griseofulvin is a hepatic enzyme inducer; thus it reduces the half-life of other drugs metabolized by CYP3A4.
    • Lots of interactions!!!
    • Half-life is 24 hours
  12. Griseofulvin SE:
    • Photosensitivity
    • GI upset
    • Headache
    • Dizziness
    • Rash
    • Urticaria
    • Confusion
  13. Giseofulvin CI:
    • Porphyria
    • Pregnancy
    • Hepatic failure
    • Caution if hypersensitive to penicillin
  14. Polyenes drugs:
    • Amphotericin B
    • Nystatin
  15. Polyenes MOA:
    • Cholesterol, found in human cell membranes and ergosterol, found in fungal cell membranes, are examples of sterols.
    • Polyenes bind sterols.  They bind ergosterol with higher affinity than cholesterol.
    • Polyenes bind to ergosterol and create channels in the fungal membrane.
    • Ions leak out of the channels, killing the cell
    • Binding of polyenes  to cholesterol is responsible for the toxicities.
    • The polyenes become integrated into the fungal membrane and pores are formed
  16. how can resistance develop?
    less affinity
  17. indication for Ampho B?
    Serious invasive or systemic fungal infections
  18. polyenes warning?
    • Amphotericin B is frequently the only effective treatment available for potentially life-threatening fungal disease.
    • In each case, its possible life-saving benefit must be balanced against its dangerous side effects.
  19. what are Amphotericin formulations?
    • formulations are not bioequivalent!
    • Amphotericin B salts
    • Liposomal amphotericin:  this formulation incorporates the drug into small lipid vesicles
    • Amphotericin B lipid complex (ABLC) : a non-liposomal formulation that complexes with two phospholipids
  20. polyenes kinetics:
    • Amphotericin has a long half-life  (15 days)
    • It accumulates in and is slowly released from tissues
  21. polyenes SE:
    • Nephrotoxicity
    • Infusion reactions*
    • Electrolyte abnormalities
  22. nystatin indications:
    • Noninvasive candidal infections, including·         oropharyngeal thrush·  
    • vaginal candidiasis·        
    • intertriginous candidal infections
  23. clinical applications of nystatin:
    The yeast Candida Albicans can cause thrush
  24. symptoms of thrush:
    • Curd-like patches inside the mouth·        
    • Oral thrush is common in babies, young kids, immunocompromised and the elderly
  25. kinetics of nystatin:
    • Too toxic for parenteral administration
    • Poor oral absorption
    • Used topically and as an oral rinse (swish and swallow)
  26. Pyrimidine antifungal drugs:
    Flucytosine (Ancoban)
  27. Pyrimidine antifungals MOA:
    • Flucytosine interferes with DNA & RNA replication
    • Flucytosine is transported in  to susceptible fungi by an enzyme called, cytosine permease, only present in fungi.
    • Flucytosine is converted to 5-fluorouracil  (5-FU) which is then converted to  (5-FDUMP).
    • 5-FDUMP is an irreversible inhibitor of thymidine synthetase needed for DNA replication.
    • How does it block protein synthesis? Acts like an analog§  Blocks RNA and DNA synthesis
  28. indications for the pyrimidine antifungals:
    • Severe fungal infections ·        
    • Nausea or vomiting may be reduced or avoided if the capsules are given a few at a time over a fifteen minute period.
    • Flucytosine should be used in combination with amphotericin B due to the emergence of resistance to flucytosine
  29. pyrimidine antifungals kinetics:
    • Given orally; well absorbed
    • Renal elimination; thus dosage adjustments required in renal impairment
  30. pyrimidine antifungals BBW:
    renal impairment
  31. pyrimidine SE:
    • Cardiac arrest
    • Respiratory arrest
    • GI bleed
    • Renal failure
    • Bone marrow suppression
    • Toxic epidermal necrolysis
    • hepatotoxocity
    • Common; chest pain, dyspnea, rash, N&V, abdominal pain, diarrhea
  32. Lamisil drugs:
    • Terbinafine (Lamisil)      
    • Topical formulation (Lamisil AT)
  33. Lamisil MOA
    • Remember, ergosterol is a component of the fungal cell membrane
    • Terbinafene blocks the production of lanosterol via inhibition of sqaulene epoxidase.
    • Results in a decrease in ergosterol production
  34. Lamisil indications:
    • Fungal infection of the nails
    • Tinea capitus
    • Tinea pedis, tinea corporis & tinea cruris·         (usually topical)
  35. Lamisil kinetics:
    • Metabolized by the liver
    • Lipid soluble; distributes into nails, skin & fat
    • Long half-life
    • Avoid use is CrCl <50
    • Avoid use in hepatic impairment
  36. Lamisil SE:
    • Liver failure
    • Stevens Johnson syndrome
    • SLE exacerbation
    • Psoriasis exacerbation
    • Anaphylaxis
    • Neutropenia
    • Also; headache, fever, upper respiratory infection, cough, rash, dyspepsia
  37. Lamisil treatment duration for-
    • Fingernails: 6 weeks
    • Toenails: 12 weeks
Card Set:
ID: Echinocandins, griseofulvin, Polyenes, Pyrimidine, Antifungals, Lamisil
2013-06-22 00:21:30
ID pharm echinocandins Griseofulvin polyenes

ID pharm exam 2
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