Antimyotics

Question 1

What are the 2 categories fungal disease falls under?

Answer 1

• dermatophytes
• internal disease

Question 2

What fungus causes guttoral pouch mycosis?

Answer 2

aspergillus spp

Question 3

What action do most antimycotic drugs have?

Answer 3

Fungistatic

Question 4

What is the TI of most antifungals?

Answer 4

Low so side effects at higher conc

Question 5

What are the 4 main antimycotics? (that effect the cell wall)

Answer 5

• polyenes
• azoles
• terbinafine
• echinocandins

Question 6

What is the cholesterol equivelent in fungal cells?

Answer 6

Ergosterol

Question 7

What is amphotericin B and what produces it?

Answer 7

Polyene proudced by some bacteria

Question 8

What does amphotericicn B attach to?

Answer 8

ergosterol

Question 9

Action of Amphotericin B

Answer 9

• forms pore in membrane
• internal acidification
• leakage of cell constituents

Question 10

Is amphotericin B fungicidal or fungistatic?

Answer 10

fungistatic at concs usually used but -cidal at higher concentrations

Question 11

What spectrum is ampotericin B?

Answer 11

Borad

Question 12

How is amphotericin B given

Answer 12

IV

Question 13

What limits the use of AB?

Answer 13

nephrotoxicity
(also GI disturbances, type I hypersensitivity)

Question 14

What class of drugs does terbinafine belong to?

Answer 14

allylamin

Question 15

What part of fungal cell wall synthesis does terbinafine inhibit?

Answer 15

squalene epoxidase

Question 16

What can Terbinafine be used to treat?
(in dogs and cats)

Answer 16

dermatophytosis, subcutaneous and systemic fungal infections

Question 17

What is the most common antimycotic?

Answer 17

Azoles

Question 18

What do azoles inhibit?

Answer 18

C14a-demethylase
(a cytochrome p450 enzyme)

Question 19

What is the action of azoles?

Answer 19

• inhibits synthesis of ergosterol, leads to accumulation of precursors
• disrupts membrane-bound enzyme activity
• inhibits cell growth

Question 20

How are azoles administered?

Answer 20

orally
(also available as topical and IV formulations)

Question 21

What is the Spectrum of azoles

Answer 21

• broad
• against skin or systemic infections

Question 22

What is azole toxicity like ?

Answer 22

• relatively non toxic
• can cause nausea, vomiting, liver toxicity

Question 23

How can fungal resistance occur in azoles?

Answer 23

• mutations in lanosterol 14alpha demethylase
• increased expression of lanosterol 14alpha demethylase
• expression of an azole efflux pump

Question 24

What do echinocandins inhibit?

Answer 24

1,3-beta glucan synthase

Question 25

What is the Echinocandin mechanism?

Answer 25

• reduce glucan synthesis
• glucans help maintain cell wall structure
• cell loses integrity and lyses

Question 26

What are echinocandins useful for and an example of one?

Answer 26

• treating systemic aspergillosis and otehr fungal infections
• Capsofungin

Question 27

What is Flucytosine

Answer 27

nucleoside analog, inhibits DNA and RNA synth

Question 28

What is Griseofulvin

Answer 28

binds to microtubules and inhibits mitosis and cell growt