Antifungals

Question 1

polyenes

Answer 1

natural compounds - wide spectrum

form a pore structure which allows cations to leak out - K+, Na+

Question 2

polyenes are a subgroup of

Answer 2

macrolides

Question 3

examples of polyenes

Answer 3

Ampheterin B - Iv old

nystatin - oral - yeast infections in the mouth and stomach

Question 4

polyenes associate with

Answer 4

ergosterol

Question 5

nyastatin

Answer 5

oral/stomach yeast infections

- not absorbed into the blood stream, won’t treat fungal infections in other parts of the body or skin

Question 6

Am B x10 more

Answer 6

specific for ergosterol than cholesterol

Question 7

polyenes are typically obtained from

Answer 7

streptomycin bacteria

Question 8

polyenes feature and treat

Answer 8

features large cyclic ester ring and are used to treat mild thrush

Question 9

Ampheterin B - produced by, development,

Answer 9

streptomyces nodosus

- development of lipid based formulation, hydrophilic which has enhanced the ability to limit toxicities

Question 10

resistant to polyenes

Answer 10

Candida Lusitania

aspergillus terres and trichophyton

Question 11

Ampheterin B is normally combined with …

Answer 11

deoxycholate

-permits IV administration

Question 12

AmB general

Answer 12

poor absorption into the CSF

can also be used topically - GI, urinary infection

Question 13

Azores - strusture

Answer 13

• largest group of antifungals
• 5 approved for systemic infections
• 5 membered heterocyclic ring - 1 or more N/O/S atom

Question 14

imidiazole

Answer 14

2N atoms
rarely used
toxicity and specificity problems\

Question 15

voriconazole

Answer 15

methyl group allows activity against aspergillus

Question 16

Azoles action

Answer 16

inhibit 14a sterol demethylase - blocks in the heme ion in the enzyme - fungistatic

block - iansterol –> eburicol

Question 17

issues with azoles

Answer 17

drug interactions - they are metabolised by cytochrome P450 enzymes in the liver
resistance

Question 18

what do azoles not treat

Answer 18

aspergillus - except voriconazole (methlgroup)

Question 19

which enzyme do azole inhibit

Answer 19

CYP3A4

Question 20

which drug should care be take when azalea are administered with

Answer 20

rifampicin - another drug which is metabolised by CYP3A4 - build up

Question 21

what are azaleas the initial choice for

Answer 21

rapidly progressing severe systemic infections

Question 22

histoplasma and blastomycosis

Answer 22

alzoles

Question 23

what resistance to azoles

Answer 23

protein phosphatase calcineurin allows survival during membrane stress by azoles

Question 24

achieves greater levels in CNA in patients with dissemination infections

Answer 24

voriconozole

Question 25

Allylamine

Answer 25

synthetic compounds, inhibit ergosterol synthesis - inhibit squalene epoxidase squalene accumulates in the cell which is toxic to the cell

Question 26

allylamines are active against

Answer 26

dermatophytes

Question 27

allylamines are poorly active against

Answer 27

candida, aspergillus and cryptococcus neoformins

Question 28

example of a allylamine -

Answer 28

terbinafine

Question 29

terbinafine

Answer 29

inhibits onchomycosis - tine ungium - nails inhibits squalene epoxidase topical or oral tablet proven efficacy at penetrating kerinized tissues no effect on human sterol synthesis highly lipophilic - high nail, sebum conc.

Question 30

terbifinafine is a potent inhibitor of which enzyme

Answer 30

CYP2D6

Question 31

topical Allylamine

Answer 31

naftifine

Question 32

what would you use to treat systemic aspergillosis

Answer 32

terbinafine and intraconazole together