Antifungals

Question 1

Are fungi prokaryotes or eukaryotes?

Answer 1

Eukaryotes

Question 2

True or False: Fungal metabolism is closer to mammals than it is to bacteria.

Answer 2

TRUE

Question 3

What is the MOA of azoles?

Answer 3

Interfere with ergosterol synthesis inhibition of 14a-demethylase

Question 4

Are the azoles fungicidal or fungistatic?

Answer 4

Fungistatic

Question 5

Which of the following has good bioavailability, Imidazoles or Triazoles?

Answer 5

Triazoles

Question 6

Which of the following is less toxic, Imidazoles or Triazoles?

Answer 6

Triazoles

Question 7

Why are Triazoles less toxic than Imidazoles?

Answer 7

Triazoles have less of an effect on mammalian metabolism than Imidazoles.

Question 8

Can you name the 3 Imidazoles?

Answer 8

1. Ketoconazole
2. Clotrimazole
3. Enilconazole

Question 9

Can you name the 4 Triazoles?

Answer 9

1. Itraconazole
2. Fluconazole
3. Voriconazole
4. Posaconazole

Question 10

What are the 4 adverse effects associated with azoles?

Answer 10

1. Hepatitis
2. Ulcerative skin lesions (Itraconazole)
3. Teratogenic
4. Inhibition of mammalian P450 (interferes with metabolism of other drugs)

Question 11

Which azole has the greatest likelihood of causing hepatitis, Ketoconazole, Itraconazole, or Fluconazole?

Answer 11

Ketoconazole

Question 12

Is Amphotericin B fungicidal or fungistatic?

Answer 12

Fungistatic –> Fungicidal at high doses

Question 13

What is the adverse effect associated with Amphotericin B?

Answer 13

Nephrotoxicity

Question 14

What is 5-Flucytosine effective against?

Answer 14

1. Cryptococcus

2. Candida

Question 15

Is 5-Flucytosine fungistatic or fungicidal?

Answer 15

Fungistatic

Question 16

What are the 3 adverse effects associated with 5-Flucytosine?

Answer 16

1. Cutaneous drug eruptions in dogs
2. Myelosuppression
3. Resistance develops quickly

Question 17

How can you avoid the quick resistance that develops to 5-Flucytosine?

Answer 17

Always combine 5-Flucytosine with another anti-fungal to limit resistance.

Question 18

5-Flucytosine is an analog of what?

Answer 18

Pyrimidine

Question 19

5-Flucytosine is a fluorinated pyrimidine that interferes with _____ when converted to fluorouracil.

Answer 19

DNA replication

Question 20

What is the MOA of terbinafine?

Answer 20

Inhibition of squalene epoxidase, causing intracellular accumulation of squalene, which is toxic to cells, causing cell lysis.

Question 21

Is terbinafine fungistatic or fungicidal?

Answer 21

Fungicidal

Question 22

What adverse effect of terbinafine has been reported in the cat?

Answer 22

Facial pruritis