Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology Part 2 > Lec41 Antifungals > Flashcards

Lec41 Antifungals Flashcards

(68 cards)

Start Studying
1
Q

What are the 3 main targets for antifungal therapy?

A

cell membrane: fungi use argosterol instead of cholesterol
DNA synthesis: restricted to serious infections because more side effects
cell wall: fungi have cell wall, we do not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are two types of cell wall inhibitors?

A

inhibitors of glucan synthesis = echinocandins

inhibitors of chitin synthesis = nikkomycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is mech of action of cell membrane inhibitors? example?

A

they inhibit ergosterol synthesis

- azoles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of antifungal causes direct cell membrane damage?

A

polyenes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the two types of polyene antibiotics?

A
  • amphotericin B

- nystatin [topical]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the classifications of systemic azole antibiotices?

A

imidazoles: ketoconazole
triazoles: itraconazole, fluconazole,
2nd gen triazoles: voriconazole, posaconazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are benefits of azoles for systemic use?

A
  • broad therapeutic window, wide spectrum of activity, low toxicity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is mech of action of azoles?

A
  • bind lanosterol 14a-demethylase a P450 enzyme responsible for production of ergosterol
  • thus blocks ergosterol production
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are potential side effects of azoles?

A
  • azoles act by blocking a fungus cyt p450 enzyme, may see cross reactivity with human cyt p450
  • – drug interactions
  • – impairment of steroidneogenesis [keto, itra]
  • nausea, vomiting, rash –> more likely with high doses and AIDS
  • may cause hepatotoxicity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are advantages and disadvantages of fluconazole?

A

advantages: low side effects, both IV/PO formations, high bioavailability
- favorable pharmacokinetics

disadvantages: fungistatic, resistance is increasing, narrow spectrum, possible p450 drug interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is fluconazole good for treating?

A
  • primarily used for Candida albicans, cryptococcus neoformans
  • also active against dermatophytes [trichophyton], dimorphic fungi
  • see primary resistance in many non-albicans candida
  • -> C. krusei always resistant
  • -> C glabrata often resistant
  • -> tropicalis rarely resistant
  • no activity against aspergillus or most mould fungi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are fluconazoles drug interactions

A
  • iincreases phenytoin, cyclosporin, rifabutin, warfarin, zidovudine conc
  • rifampin reduces fluconazole level to half
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Can fluconazole penetrate CSF?

A

yes very well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is bioavailability to fluconazole?

A

very high >90% means little difference between oral and IV forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What can itraconazole treat?

A
  • similar candida coverage as fluconazole [C albicans, C tropicalis, sometimes C. globrata, never C. krusei]
  • also can treat aspergillus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is fluconazole cleared?

A

mostly renal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is itraconazole excreted?

A
  • hepatic metabolism and via bile
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Can itraconazole pentetrate the CSF?

A

nope! so not good for meningeal fungal infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Is there an oral form of itraconazole?

A

yep but not very good absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what can voriconazole treat?

A
  • very broad
  • includes most candida, aspergillus, fusarium
  • can’t treat zygomycoses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Is there an oral form of voriconazole?

A

Yep with >90% bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is voriconazole cleared?

A

mostly hepatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Can voriconazole penetrate CSF?

A

Yep! good for meningitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are adverse side effects of itraconazole?

A
  • nausea and vomitting
  • osmotic diarrhea
  • taste disturbances
  • maybe hepatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are adverse side effects of voriconazole?
- nausea and vomitting - visual disturbances [reversible, decreased vision, altered color perception, worse with IV than oral] - hallucination in 2-5% - hepatic - rash
26
Of fluconazole, itraconazole, and voriconazole whihc have most drug interactions?
- itraconazole has strong interactions - voriconazole moderate - strong - fluconazole weak inhibit cyp 34A
27
What is fluconazole usually used to treat?
- invasive or mucocutaneous candidiasis - maintenance therapy for cryptococcal meningitis - coccidiodomycosis
28
What is itraconazole usually used to treat?
- azole of choice for invasive histoplasma, blastomycosis, sporothrix - dermatophyte infections and onychomycosis
29
What is voriconazole usually used to treat?
- drug of choice for invasive aspergillosis | - cancer/neutropenia prophylaxis
30
What is posaconazole usually used to treat?
- prevent mold infections in patients with neutropenia/cancer [only have oral form
31
How is psaconazole administered? what is it used to treat?
- broad activity including against zygomycetes - only oral form - requires fatty meal for absorption - use for prophylaxis prevention of invasive mold infections in pts at risk
32
What is terbinafine used to treat?
- its a systemic antifungal agent but used to treat superficial fungal infections - mainly used for onychomycosis
33
What is mech of terbinafine? side effects?
- interferes with ergosterol synthesis - no drug interactions - can cause liver inflammation
34
How is terbinafine administered?
orally
35
What is nystatin? what do you treat? side effects?
- a topical polyene - treat mucocutaneous candidiasis [oral thrush] - little toxicity
36
What is clotrimazole? what do you treat? side effects?
- a topical azole antifungal - treat mucocutaneous candidiasis, dermatophyte infections - little toxicity
37
What is amphotericin B? mech of action?
- amphoteric polyene macrolide - binds sterols in fungal cell membrane - creates transmbembrane channel and electrolyte leakage [creates pores]
38
What is amphotericin B active against?
active against most fungi except aspergillus terreus, scedosporium
39
What are side effects of original amphotericin? what are the new preparation?
- classic formulation --> serious toxic side effects, renal damage - lipid associated formulations make it less toxic [liposomal amphotericin B {L-AMB}, amphotericin B colloidal dispersion {ABCD}, amphotericin B lipid complex {ABLC}]
40
What are the drug names for the 3 different lipid formulatiosn of amphotericin B?
``` ambisome = L-AMB albecet = ABLC amphotec = ABCD ```
41
What are side effects of amphotericin B as administered?
- renal toxicity - --- increase renal vascular resistance --> low GFR, azotemia = accumulation of urea in blood stream - --- increase tubular permeability --> distal tube ischemia, wasting of K, Na, Mg - get bigger renal effects in pts volume depleted or on concomitant nephrotoxic agents --> MAKE SURE PT HAS FLUIDS
42
What is amphotericin B used to treat?
- standard antifungal therapy --> drug of choice for: - -- cryptococcal meningitis - -- mucormycosis in combo with surgery - -- induction therapy for histoplasmosis - -- invasive fungal infections that don't respond to other therapy - cannot tret: aspergillus terreus, scedosporium, some candida lusitanae, maduralla, some paecilomyes
43
What is flucytosine [5FC]? administration?
- anti-metabolite against DNA/RNA symthesis - marketed as Ancotil - IV or oral administration
44
What are side effects of fluytosine [5FC]? When do you particularly need to monitor?
- vomitting, diarrhea - altered liver function tests - bone marrow toxicity - need to monitor blood conc of drug when used in conjunction with amphotericin B
45
What do you treat with flucytosine?
- fungistatic and fungicidal acativity against yeasts, only fungistatic against aspergillus fumigatus
46
What is mech of action of echinocandins?
- inhibit fungal cell wall synthesis of glucan | - loss of cell wall glucan --> osmotic fragility
47
What can echinocandins be used to treat?
- fungicidal against: most candida species including non-albicans, pnseumocystis carinii - acive but usually not fungicidal against: aspergillus - no activity against cryptococcus neoformans - no activity against other molds: fusarium, zygomycosis, trichosporon
48
What are 2 drugs of choice for aspergillus?
- floriconazole | - amphotericin
49
What are the 3 echinocandins?
- capsofungin - micafungin - anidulafungin
50
What are adverse effects of capsofungin?
- mostly mild and do not require treatment discontinuation - usually infusion related: intravenous site irritation, mild to moderate infusion related fever/headache/flushing/erythema/rash - asymptomatic increase serum transaminases
51
What are common causes of fungal endopthalmitis?
- candida albicans most common [slow progression, better prognosis] - aspergillus [rapid progression, vision threatening]
52
What are predisposing factors to fungal endopthalmitis?
- invasive disease - immunosuppression - malignancy - long term broad spectrum antibiotics - neutropenia - organ transplant - dialysis - AIDS - liver disease - indwelling cathers - IV drug use
53
What are signs of fungal endopthalmitis?
- decreased vision - photoboia - pain - red eye - viritis [esp. in aspergillus] - pseudo-hypopynon [layering exudate] - retinal findings
54
What is treatment for fungal endopthalmitis?
- usually systemic amphotericin + intravitreal administration - or: systemic fluconazole, systemic flucytosine, systemic and intravitreal voriconazole
55
Which fungi are dimorphic?
- histoplasma - coccidioides - blastomyces - paracoccidioides - penicillium
56
What are major treatments for candida?
- fluconazole - amphotericin - echinocandins
57
What are major treatments for cryptococcus neoformans?
- amphotericin [maybe with combined 5FC] | - fluconazole for prophylaxis
58
What are major treatments for histoplasma?
- amphotericin - itraconazole - voriconazole
59
What are major treatments for blastomyces dermatidis?
- amphotericin - itraconazole - fluconazole
60
What are major treatments for coccidioides?
- amphotericin | - then fluconazole in immunosuppressed
61
What are major treatments for paracoccidioides brasiliensis?
- itraconazole, amphotericin B, or TMP-SMX
62
What are major treatments for penicillium marneffei?
- amphotericin and 5FC
63
What is treatment for zygomytes?
- surgical debridement with amphotericin | - posaconazole for prophylaxis
64
What is treatment for aspergillus?
- voriconazole or amphotericin for invasive disease
65
What is treatment for pnseumocystis jiroveci?
- TMP-SMX
66
What is major treatment for topical dermatophytes
topical meds -->
67
What is major treatment for eumycetoma?
- surgical | - posaconazole on compassionate bases
68
What is major treatment for sporotrichiosis?
- itraconazole [sporonox]

Microbiology Part 2 (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions