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Flashcards in antifungals Deck (43):
1

potential antifungal targets

membranes (ergosterol), nucleic acids, cell wall

2

drugs used for systemic fungal infections (full list)

amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole, caspofungin

3

effective (brad-spectrum agent) for most serious systemic mycoses, esp life-threatening ones. ONLY use for proven or highly suspected systemic infections

amphotericin B

4

amphotericin B mechanism of action

very lipophilic, inserts into fungal membrane, binds ergosterol, increases pores/leakiness

5

amphotericin side effects

fever, N/V, HA, chills, hypotension, hypokalemia, tachypnea. 90% get nonpermanent nephrotoxicity. total cumulative dose important for reasons of permanent renal toxicity. reversible hypochromic, normocytic anemia

6

used for serious infections (candida, cryptococcus), synergistic with amphotericin B (permits reduction of dose), fungistatic

flucytosine

7

flucytosine mechanism of action

acts on cytosine permease

8

flucytosine side effects

N/V, diarrhea, enterocolitis, leukopenia, thrombocytopenia, reversible elevated hepatic enzymes. use caution with renal insufficiency or bone marrow depression. monitor closely

9

relative to amphotericin, other drugs for serious fungal infections...:

have narrower spectrum of action, not for immediately life-threatening infections, have fewer/less serious side effects

10

triazoles for serious fungal infections (imidazoles also used)

fluconazole, itraconazole, voriconazole

11

MOA for imidazoles and triazoles

inhibit 14-a-sterol demethylase, a fungal cytochrome P450 that converts lanosterol to ergosterol. inhibits ergosterol synthesis --> membrane instability

12

used for cryptococcus (esp after amphotericin therapy), candida at many sites including CNS and urinary, some albicans and galbrata, NOT krusei

fluconazole

13

used for blastomyces, histoplasma, candida (not CNS & urinary), more c. albicans and galbrata

itraconazole

14

used for aspergillus, fusarium, scedosporium, candida (not urinary), covers many candida spp including galbrata and krusei

voriconazole

15

which azole has CNS penetration and has active drug in urine?

fluconazole

16

azole side effects

N/V, rash, diarrhea, headache, mild hepatotoxicity (discontinue with onset of liver dysfunction), inhibit metabolism of several other drugs (CYP 3A and 2C family inhibitors)

17

itraconazole contraindications

DO NOT GIVE with other drugs that are metabolized by CYP 3A4. potential for serious CV events including death

18

which azole has lowest incidence of hepatotoxicity?

fluconazole

19

voriconazole side effects

visual disturbances (30%), rash with photosensitive component

20

antifungal that targets cell wall

caspofungin

21

uses of caspofungin

invasive aspergillus, candida (esophageal and systemic)

22

caspofungin MOA

inhibits fungal cell wall synthesis by noncompetitively blocking synthesis of B(1,3)-D-glucan in filamentous fungi. no cross resistance with azoles

23

caspofungin side effects (based on limited experience)

generally well-tolerated, but fever, N/V, flushing, phlebitis at injection site

24

drugs for treatment of superficial mycoses

nystatin, fluconazole, miconazole, ketoconazole, clotrimazole, itraconazole, natamycin

25

treatment for superficial candidiasis (vaginal, urinary tract, oropharynx)

fluconazole

26

cream/suppository for vaginal candida, causes itching/burning

miconazole

27

topical or oral troche use for candida, not opthalmic. allergic/irritation reactions. oral troches cause?

clotrimazole.
oral troches cause abnormal liver function tests

28

used for oropharyngeal and esophageal candida

itraconazole

29

effective against azole-resistant strains, topical use for candida (not opthalmic), oral for GI candida (can cause GI distress)

nystatin

30

treatment of opthalmic fungal infections

natamycin

31

natamycin toxicity

conjunctival chemosis and hyperemia

32

causative agents for dermatophytic infections

trichyphyton, epidermophyton, microsporum

33

topical treatments for dermatophytes

miconazole, clotrimazole, tolnaftate, terbinafine, ciclopirox

34

only FDA-approved topical rx for mild-to-moderate fungal nail infections

ciclopirox

35

dermatophyte therapy-- oral preparations use

sever dermatophyte infections, those that are refractory to topical therapy

36

12-week therapy for nail infections, shorter for other dermatophytic infections

terbinafine

37

terbinafine mechanism of action

blocks squalene epoxidase so squalene (toxic) builds up. fungicidal.

38

terbinafine side effects

diarrhea, dyspepsia, abdominal pain

39

for recalcitrant dermatophytic infections of skin, hair, nails. therapy for kids esp tinea capitis

griseofulvin

40

griseofulvin mechanism

interferes with microtubule function/mitotic spindle/mitosis

41

griseofulvin side effects

low incidence. contraindicated in those with porphyria and advanced liver disease. increased metabolism of several drugs (CYP inducer). use with caution if penicillin allergy.

42

oral 3-month therapy for fungal toenail infections

itraconazole

43

side effects of itraconazole

N/V, rash, diarrhea, headache, edema, inhibits metabolism of many drugs, discontinue with signs of liver dysfunction