Antimicrobial Chemotherapy 2 Flashcards Preview

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Flashcards in Antimicrobial Chemotherapy 2 Deck (45)
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1

What can fungi be divided into

Yeasts
Filamentous fungi (moulds)

2

What can be used to treat fungi

Anti-fungal drugs

3

What are the categories of anti-fungal drugs

Polyenes
Azoles
Allylamines
Echinocandins

4

What is the mechanism of action for polyenes

They bind to ergosterol that is present in the fungal cell wall but not in the bacterial cell wall
This results in an increase in the permeability of the cell wall

5

What are polyene drugs active against

Yeasts
Filamentous fungi

6

What is a disadvantage of polyene drugs

They bind to other sterols (e.g. cholesterol) in mammalian cell membranes and this is the reason for their toxicity

7

Which polyene can be used intravenously and what is it used for

Amphotericin B
Used for serious systemic fungal infection

8

Describe amphotericin B

It is exteremely toxic and has a wide range of side effects (e.g. renal, hepatic and cardiac toxicity)
The lipid complexed formulations of this drug offer a reduced incidence of such side effects

9

What is nystatin

A polyene drug available for topical use only

10

What do azoles do

Inhibit ergosterol synthesis

11

Name some azoles

Old:
Miconazole
Ketoconazole
Newer:
Fluconazole
Voriconazole
Itraconazole

12

Describe fluconazole

Used for oral and parenteral treatment of yeast infections
Has no serious toxicity problems
Resistance among some Candida species is emerging
Resistance can emerge during treatment

13

Describe itraconazole

Active against both yeasts and filamentous fungi, including Aspergillus spp. and dermatophytes.

14

What does voriconazole treat

Aspergillosis

15

Describe the mechanism of action for allylamines

They suppress ergosterol synthesis but act at a different stage of the synthetic pathway from azoles

16

Name an allylamine

Terbinafine (only one in common use)

17

What are allylamines active against

Dermatophyte infections of the skin
(e.g. ringworm, athlete’s foot) and nails (onychomycosis)

Mild infections will be treated topically and more serious infections
(including onychomycosis) orally

18

Describe the mechanism of action for echinocandins

They inhibit the synthesis of glucan polysaccharide in several types of fungi

They are fungicidal against the Candida species and inhibit the growth of several Aspergillus species

19

Name some echinocandins

Micafungin
Caspofungin
Anidulafungin

20

What does virustatic agents

Those that inhibit growth and/or replication

21

What are virucidal agents

Those that will kill the virus

22

Are anti-viral drugs virucidal or virustatic

Virustatic

23

How do anti-viral drugs tend to work

Many are nucleoside analogues which
interfere with nucleic acid synthesis

24

How can the treatment of herpes be effective

If started early
Will not erdicate any of the viruses

25

What do anti-herpes virus drugs treat

Herpes simplex virus
Cytomegalovirus
Varicella-zoster virus
Epstein-Barr virus

26

What is aciclovir

An anti-herpes virus drug
A nucleoside analogue

27

What is aciclovir active against

Herpes Simplex
Varicella Zoster

28

What must occur for aciclovir to become active

Be converted into its active form by an enzyme (thymidine kinase) coded for by the virus genome

29

What is an advantage of aciclovir

It's specific for virus-infected cells and
has very low toxicity for uninfected host cells

30

When is the IV and oral forms of aciclovir used

IV: treats severe infections (e.g. herpes encephalitis and VZV pneumonitis)
Oral: cold sores (caused by HSV reactivation)