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Flashcards in Antifungals Deck (37):
1

Name the polyenes

amphotericin B and Nystatin

2

MOA of polyenes

interact with ergosterol in fungal membranes to form artificial "pores" = FUNGICIDAL

3

Polyene resistance mech.

low ergosterol content in cell membrane

4

What is Amphotericin B used for?

Aspergillus, Candida, Cryptococcus, Histoplasma, Mucor, Sporothrix

5

What is the broadest spectrum antifungal on the market?

Amphotericin B

6

What antifungal is used in combo with flucytosine to treat candida and cryptococcus?

Amphotericin B

7

How is nystatin used?

TOPICALLY
too toxic for systemic use

8

How is Amphotericin B administered?

slow IV infusion
poor CNS penetration (requires intrathecal admin. in CNS infection)
slow clearance and t1/2=2 wks

9

How is Amphotericin B toxicity reduced?

liposomal preparation

10

Polyene S.E.?

dose-dependent nephrotoxicity

11

Most common SE of Amphotericin B?

severe fever and chills
tx with aspirin, or acetapminophen, or corticosteriods, or Meperidine
*also SE: rhinocerebral phycomycosis

12

What drug can cause oral candidiasis?

aerosolized beclomethasone (asthma)

13

MOA of azoles?

fungicidal: interfere with synthesis of ergosterol (aka 14alpha demethylase, a CYP450!)

14

Azole resistance?

decreased intracellular accumulation of azoles

15

Ketoconazole use?

co-DOC for paracoccidioides, backup for blastomycoses and histoplasma

16

Fluconazole use?

DOC for esophageal and invasive candidiasis and coccidioidomycoses
prophylaxis for cryptococcal meningitis

17

Itraconazole use?

DOC in blastomycoses, sporotrichoses, aspergillosis, backup for other mycoses

18

Voriconazole use?

same as Itraconazole
(DOC in blastomycoses, sporotrichoses, aspergillosis, backup for other mycoses)

19

Clotrimazole and miconazole use?

TOPICAL--> candida, dermatophytic infections

20

Azole admin?

oral (except clotrimazole and miconazole)

21

How does antacid use affect ketonazole absorption?

decreases

22

How does food intake affect itraconazole absorption?

increases

23

Drug interactions with azoles?

YES because it inhibits the P450s

24

SE of azoles?

decreased synthesis of steriods (cortisol, testosterone)--> decreased libido, gynecomastia, menstrual irregularities
increase LFTs
Rare hepatotoxicity

25

Flucytosine MOA?

activated by fungal cytosine --> 5FU --> triphosphorylation--> incorporated into fungal RNA
5FU--> 5-Fd-UMP--> inhib. thymidylate synthase--> decrease thymine (DNA)

26

Flucytosine resistance?

YES, if used alone

27

Flucytosine use?

USE WITH AMPHOTERICIN B
in severe cadidal and cryptococcal infections (enters CNS)

28

Flucytosine SE?

bone marrow suppression

29

Griseofulvin use?

active only against dermatophytes
ORAL
**distributes only where keratin is

30

Griseofulvin SE?

Disulfiram like rxn

31

Terbinafine use?

active only against dermatophytes
*may be superior to Griseofulvin in onychomyces

32

Terbinafine MOA?

inhib. squalene epoxidase--> decreases egosterol

33

Terbinafine SE?

GI distress, rash, headache, increased LFTs, hepatotox.

34

Caspofungins MOA?

block glucan synthesis (cell wall)

35

Name one Caspofungins

Micafungin

36

Micafungin use

invasive candidiasis and aspergillosis esp. in HIV pts

37

Caspofungin SE

GI distress, flushing