EXAM #4: ANTIFUNGALS Flashcards Preview

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Flashcards in EXAM #4: ANTIFUNGALS Deck (54):
1

List the systemic fungi.

- Histoplasma capsulatum
- Blastomyces dermatiditis
- Coccidioides immitis
- Sporothrix schenckii

2

List the opportunistic fungi.

- Candida
- Aspergillus
- Cryptococcus neoformans

3

What are the common cutaneous and subcutaneous fungal infections?

Sporothrix schenckii
Dermatophytes
- Ringworm
- Athlete's Foot
- Onychomycosis

4

What are the unique targets used in antifungal therapy?

- Fungal cell membrane i.e. ERGOSTEROL
- Fungal cell wall i.e. GLUCANS

5

List the drugs that inhibit Ergosterol synthesis.

Azoles
Naftidfine
Terbnafine

6

What drug inhibits fungal membrane function?

Amphotericin B

7

What drug inhibits fungal cell wall synthesis?

Caspofungin

8

What drug inhibits fungal nuclei acid synthesis?

5-fluorocytosine

9

What drugs can be used to treat systemic fungal infections?

1) Polyenes- amphotericin B
2) Azoles
3) Flucytosine
4) Echinocandins

10

What drug has the broadest spectrum of all the antifungals?

Amphotericin B

11

Why has Amphotericin B been replaced for newer compounds?

High degree of toxicity

12

What is the MOA of Amphotericin B

- Binds ergosterol in fungal cell membrane
- Forms Amp B pores in fungal membrane

13

Why is there high toxicity associated with Amphotericin B?

Not only binds ergosterol, but can also bind cholesterol

14

What is Amphotericin B the treatment of choice for?

1) Disseminated candidasis
2) Cryptococcal (neoformans) meningitis

*Note that it is a second line treatment for systemic disease caused by molds*

15

What is the mechanism of resistance of Amphotericin B?

Decreased membrane ergosterol concentration

16

How is Amphotericin B administered?

*Note that it is INSOLUBLE in water*
- Complex-ed to a bile salt
- Given IV

17

How is Amphotericin B administered for Cryptococcal meningitis?

Intrathecal

18

What are the adverse reactions seen with Amphotericin B?

1) Infusion reaction seen in nearly all patients
2) NEPHROTOXICITY

19

How is the toxicity of Amphotericin B being combated?

Packaging the drug in lipid micelle i.e. "liposomal packaging"

20

What are the two groups of Azoles?

1) Imidazoles (2x nitrogens)
2) Triazoles (3x nitrogens)

21

List the imidazoles.

Ketoconazole
Miconazole
Clotrimazole

22

List the triazoles.

Fluconazole
Itraconazole
Voriconazole
Posaconazole

23

What is the MOA of the azoles?

Inhibit the enzyme the produces ergosterol
- Makes the cell membrane leaky

24

What are the mechanisms of resistance to the azoles?

1) Drug efflux pumps
2) Mutation in target enzyme
3) Decreased ergosterol synthesis

25

Why is Ketoconazole rarely used clinically today?

Toxicity

26

What is the typical first line drug for systemic fungal infections?

Fluconazole

27

Why is Fluconazole highly utilized in the treatment of systemic fungal infections?

- Highest TI
- Distributed to the CNS
- Few drug-drug interactions

28

What is Fluconazole a first ling agent for?

1) Systemic Candidiasis
2) Cryptococcosis
3) Coccidiomycosis

29

How does Itraconazole compared to Fluconazole?

Broader spectrum of activity BUT lower TI

30

What does Itraconazole require for absorption?

Low GI pH

31

Can Itraconazole penetrate the CNS?

NO

32

What is Itraconazole the drug of choice for?

adf

33

What is Voriconazole?

Derivative of Fluconazole

34

What is Voriconazole commonly used to treat?

Aspergillosis

Note that it has replaced Amphotericin B as the first line drug b/c of lower toxicity.

35

What is the major adverse reaction associated with Voriconazole?

Visual disturbances

36

What drug has the broadest spectrum of all the azoles?

Posaconazole

37

What is Posaconazole used to treat?

Mucromycoses
Aspergillus

38

What is the MOA of Flucytosine?

This is a fluorinated pyrimidine analog that inhibits DNA synthesis

39

What is Flucytosine used to treat?

Used as a combination therapy for severe Cryptococcal infections

40

What are the adverse reactions seen with Flucytosine?

Bone marrow supression i.e.
- Anemia
- Leukopenia
- Thrombocytopenia

41

What is the MOA of the Echinocandins?

Inhibit the synthesis of Beta-glucan i.e. inhibit the CELL WALL

*We don't have Beta-glucan; thus, very low toxicity*

42

List the Echinocandins.

Caspofungin
Micafungin
Andidulafungin

43

What are the Echinocandins primarily used to treat?

Aspergillus
Candida

*Note that both have a high degree of Beta-glucan in their cell wall*

44

What is Griseofulvin used to treat?

This is an oral agent used to treat Dermatophyte infections

45

What is unique about Griseofulvin?

Concentrates in Keratin precursor cells
- Skin
- Hair
- Nails

46

What are Allylamines?

Class of antifungal that inhibits ergosterol synthesis

47

What is the MOA of Allylamines?

Inhibit the enzyme squalene epoxidase

48

What is the hallmark Allylamine?

Terbinafine

49

What is Terbinafine used to treat?

First line for Onychomycosis i.e. nail infections

50

What are the topical antifungal agents?

Nystatin- polyene
Clotrimazole- azole
Miconazole- azole
Terbinafine- Allylamine
Naftifine- Allylamine

51

What is the MOA of Nystatin?

Polyene that binds ergosterol and forms pores
- Only used topically

52

What is Nystatin used to treat?

Candida
- Oral
- Vagial i.e. yeast infections

53

What are the topical azoles, Clotrimazole and Miconazole used to treat?

1) Vulvovaginal candidiasis
2) Dermatophyte infections
3) Oral thrush

54

What infections are the topical Allylamines used to treat?

Tinea curis (jock-itch)
Tinea corporis (ringworm)

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