Exam 4 - Med Chem: Fungal Flashcards Preview

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Flashcards in Exam 4 - Med Chem: Fungal Deck (70)
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1
Q

Fungi Overview:
Diverse Group of _________
_____ cell wall

A

eukaryotes

rigid

2
Q

what are the two groups of fungi

A

yeast and mold…

3
Q

Yeast or Mold?

grow as single cell

A

yeast

4
Q

Yeast or Mold?

Divide asexually

A

yeast

5
Q

Yeast or Mold?

Divide by budding/fission

A

yeast (aka asexually)

6
Q

Yeast or Mold?

Filamentous multicellular aggregates (hyphae)

A

mold

7
Q

Yeast or Mold?

Grow by elongation at their tips

A

mold

8
Q

Yeast or Mold?

usually separated into cell like units by crosswalls called septa

A

mold

9
Q

4 characteristics of pathogenic fungi?

A

can grow at high temperatures
able to reach target tissues…
able to digest and absorb components of human tissues
able to withstand/evade the immune system

10
Q

3 types of fungal infections?

A

superficial/cutaneous
subcutaneous
systemic/invasive

11
Q

what are examples of superficial/cutaneous fungal infections?

A

dermatophytosis (ringworm, jock itch, athletes foot)

onchomycosis (nail fungus)

12
Q

what is a dimorphic fungi?

A

at room temperature it is hyphae (mold)

in humans or media that is 37 celsius it is yeast

13
Q

Histoplasmosis:
is caused by a _______ fungi
comes from what thing in nature?
Spore or non spore forming?

A

dimorphic endemic
bat/bird droppings
spore

14
Q

Blastomycosis:
caused by a ______ fungi
comes what thing in nature?

A

dimorphic endemic

rotting wood/soil

15
Q

Candidiasis:
Yeast or mold?
Part of ______ flora
Can be invasive but typically is localized where??

A

yeast
normal human flora
mucous membrane

16
Q

Risk Factors for Opportunistic fungal infections?

A
immunosuppression...
burn wounds/trauma
central venous catheters
broad spec abx
diabetes
renal insufficiency requiring dialysis
17
Q

Candida causes what diseases typically?

A
Cutaneous candidiasis (diaper rash, athletes foot, jock itch)
Esophagitis
Onchomycosis (nail)
Oropharyngeal (thrush)
Vulvovaginitis
18
Q

what women are at risk for vulvovaginitis?

A

diabetics
pregnant women
women treated with broad spec abx

19
Q

3 disease states of Aspergillosis

A

opportunistic infections
allergic states..
Toxicoses

20
Q

What drug is apart of the polyene antifungal class?

A

Amphotericin B

21
Q
Features of Amphotericin B:
Hydro, Lipo, or Amphi -philic?
\_\_\_\_\_ ring structure
Fungi - cidal or static?
Good or poor bioavailability?
A

Amphi!
Macrolide structure
cidal
POOR bioavail (use PO only if GI infection, use IV for systemic!)

22
Q

MOA of Amphotericin B

A

it binds to ergosterol – leads to leakage of intracellular contents

23
Q

what is egosterol

A

the main sterol in fungal cell membranes

24
Q

ADEs of Amphotericin B?

A

V toxic..
Infusion Related rxn – reduce rate of infusion if issues: fever, chills, muscle spasms, vomiting, headahces and hypotension

Renal damage!!

25
Q

________ is a polyene drug that is similar to amphotericin B but is too toxic for systemic administration/only used for superficial fungal infections

A

Nystatin

26
Q

what is a way to reduce nephrotoxicity of amphotericin?

A

put it in a lipid formulation

27
Q

Egosterol Synthesis Pathway:

________ –> ________ –> Egosterol

A

Squalene –> Lanosterol –> Egosterol

28
Q

what two drugs/classes inhibit egosterol synthesis?

A

-Azoles and Terbinafine

29
Q

terbinafine inhibits what enzyme?

A

squalene epoxidase (inhibits egosterol synthesis)

30
Q

Terbinafine:

Fungi -cidal or -static

A

cidal

happens bc too much squalene bulidup!

31
Q

Terbinafine is best for what disease states?

A

cutaneous/superficial fungal infections:

dermatophytes and onchomycoses

32
Q

Key structure part of -Azoles

A

5 membered aromatic ring

33
Q

-Azoles:

Fungi -cidal or -static

A

static

34
Q

-Azoles:

inhibit ergosterol synthesis by inhibiting what enzyme?

A

14-alpha demethylase

aka what makes lanosterol into ergosterol

35
Q

in general: what is the relationship between Azole antifungals and CYP450 enzymes

A

they are metabolized by the enzymes and they inhibit them

36
Q

Voriconazole:
metabolized by CYP_______ extensively
(genetic polymorphisms will alter levels)

A

CYP 2 C 19

37
Q

Ketoconazole:

potent ______ of CYP3A4

A

inhibitor

38
Q

Ketoconazole:
Will increase levels of _______ and _______

CYP3A4 _______ (ex: _______) will reduce ketoconazole levels

A

triazolam and cyclosporin levels increase

CYP3A4: inducers; ex rifampin

39
Q

Fluconazole:
poor or good bioavailability?
CSF penetration?

A

good bioavail

and yes CSF

40
Q

which Azole causes visual disturbances in 30% of patients (flickering lights/zigzag lines) AND is teratogenic in animals

A

Voriconazole

41
Q

Another antifungal drug class is called the Echinocandins: they are what type of molecule?

A

lipopeptide/ cyclic hexapeptide with fatty side chains

42
Q

what drugs are antifungal lipopeptides/echinocandins

A

caspofungin
micafungin
anidulafungin

43
Q

MOA of Echinocandins?

A

inhibit B(1/3) glucan aka a cell wall component by inhibiting Beta(1/3) glucan synthase

44
Q

Echinocandins:

Fungi -cidal or -static

A

cidal

45
Q

CYP interactions with Echinocandins?

A

none!!

46
Q

_______ is an antifungal drug that is a pyrimidine analog/antimetabolite

A

Flucytosine (5-FC)

47
Q

MOA of Flucytosine?

A

antimetabolite: inhibits thymidylate synthase / interferes with protein synthesis

48
Q

Flucytosine –> _____ –> ______ (which mimics ______)

A

5-FC –> 5-FU –> F-FdUMP (mimics dUMP)

49
Q

Flucytosine:
Oral or IV?
CSF?
Metabolism?

A

oral ONLY
good CSF
renally eliminated (renal impairment = toxicity)

50
Q

Griseofulvin:
From a strain of ______
Fungi - cidal or -static
Oral or IV?

A

penicillium
static
oral ONLY

51
Q

MOA of Griseofulvin?

A

disrupts fungal microtubules

52
Q

Tavaborole:

MOA?

A

inhibits leucyl transfer RNA synthetase (LeuRS) aka stops protein synthesis

53
Q

Tavaborole:

what element is essential for its activity

A

Boron

54
Q

Antifungal drug resistance:

typically transferred between strains - yes or no?

A

NO!

55
Q

Antifungal drug resistance:

main acquired resistance seen to polyenes?

A

reduced egosterol content in membrane

56
Q

Antifungal drug resistance:

main acquired resistance to Flucytosine

A

cytosine deaminase or UPRT (cytosine permease)

57
Q

Antifungal drug resistance:

Common Azole acquired resistance mechanisms?

A

target site alteration
Efflux pumps
target enzyme upregulation
Development of bypass pathways

58
Q
Antifungal Toxicities:
what drug(s) cause photopsia
A

voricaonzole

59
Q
Antifungal Toxicities:
what drug(s) cause renal toxicity
A

amphotericin B

Cyclodextrins (IV voriconazole)

60
Q
Antifungal Toxicities:
what drug(s) cause bone marrow suppresion
A
5-FC
Amphotericin B (anemia bc decrease EPO production)
61
Q
Antifungal Toxicities:
what drug(s) cause GI toxicity?
A

Itraconazole
Posaconazole
5-FC

62
Q
Antifungal Toxicities:
what drug(s) cause QT prolongation
A

all Azoles

63
Q
Antifungal Toxicities:
what drug(s) case cardiomyopathy
A

intraconzaole

64
Q
Antifungal Toxicities:
what drug(s) cause infusion reactions
A

amphotericin B

Echinocandins

65
Q
Antifungal Toxicities:
what drug(s) cause hepatic toxicity
A

all azoles
Amphotericin B
5-FC
Echinocandins

66
Q
Antifungal Toxicities:
what drug(s) cause CNS issues
A

Voriconazle

67
Q
Antifungal Toxicities:
what drug(s) can cause a rash
A

all antifungal rxns

68
Q
Antifungal Toxicities:
what drug(s) can cause photosensitivity/malignancy
A

voriconazole

69
Q

Antifungals and Pregnancy:

what antifungals are full on contraindicated?

A

voriconazole
flucytosine
griesofulvin

70
Q

Antifungals and Pregnancy:

what antifungals should be avoided in pregnant women - ESPECIALLY in 1st trimester bc birth defects/miscarriage risk

A

Fluconazole (except single 150 mg dose not a problem tho)
Itraconazole
Posaconazole
Isavuconazole