Intro to Antifungals

Question 1

What are the targets of antifungal treatment?

Answer 1

1) DNA synthesis
2) Mitosis
3) Cell wall (beta-1,3-glucans)
4) Protein synthesis

Question 2

what is ergosterol?

Answer 2

• Ergosterol is found mainly in fungal cell membranes.

- It has a role in regulation the membrane permeability.

Question 3

what is beta-1,3-glucans?

Answer 3

they make up 50-60% of the dry weight of the Fungal CELL WALL.

Question 4

Polyenes is an antifungal - how does it work?

Answer 4

Polyenes is associated with ergosterol. Causes the loss of membrane integrity and leakage of K+ , leading to cell death.

Question 5

What type of antifungals are Amphotericin B and Nystatin are examples of?

Answer 5

Polyenes (antifungal)

Question 6

Amphotericin B is effective on most fungi with medical importance.
What fungi does Amphotericin B particularily work on?

Answer 6

1) Aspergillus spp
2) Candida spp
3) Cryptococcus spp

Question 7

What are the adverse effects of Amphotericin B?

Answer 7

Allergic reaction

Nephrotoxicity

Question 8

How is amphotericin B adminstered?

Answer 8

Parenterally (anyway that is not oral)

Question 9

What is Nystatin used for?

Answer 9

superficial infections e.g. oral/vaginal candidiasis

Question 10

What is pulmonary aspergillosis?

Answer 10

fungal infection of lungs that usually affects those with an underlying condition e.g. TB, COPD.

Question 11

How do Allylamines (antifungals) work?

Answer 11

Inhibit ergosterol synthesis

Question 12

What type of antifungal is terbinafine?

Answer 12

Allylamine (works to inhibit ergosterol synthesis)

Question 13

What are the adverse effects of allylamines?

Answer 13

Liver toxicity –> jaunice, hepatitis.

Question 14

What are allylamines used for?

Answer 14

1) dermatophyte infections e.g. Athletes foot (topical use)

or Scalp ringworm (systemic oral use)

Question 15

How do Azoles work?

Answer 15

Inhibit ergosterol synthesis

Question 16

what is the spectrum of activity of azoles?

Answer 16

Broad spectrum (ie. both yeasts and filamentous fungi)

Question 17

What type of antifungal (azole) is Clotrimazole - is it a Imidazole or Triazole?

Answer 17

Clotrimazole is an Imidazole

Question 18

What type of antifungal (azole) are the following:

• fluconazole
• itraconazole
• voriconazole

Answer 18

Triazoles

Question 19

what are the adverse effects of Azoles?

Answer 19

• Hepatotoxicity

- inhibits Cytochrome P450 enzymes

Question 20

Rank the following triazoles in order of their spectrum :

fluconazole, isavuconazole, itraconazole?

Answer 20

1) Fluconazole (only works on yeast)
2) itraconazole (works on yeast and apergillus)
3) Isavuconazole (ALL)

Question 21

what are imidazoles used for?

Answer 21

Superficial infections (topical)
e.g. Candidiasis or Dermatophyte infection

Question 22

What are triazoles used for?

Answer 22

Systemic infections (oral / parenteral admin) e.g.aspergillosis / candidiasis.

Question 23

What do Echinocandins act on?

Answer 23

Inhibit beta-1,3-glucan synthase which results in abnormal cell wall construction.

Question 24

What type of antifungal is Aniidulafungin ?

Answer 24

Echinocandin

Question 25

What is the spectrum of activity of Echinocandins?

Answer 25

• Aspergillus and Candida spp.

- Misses certain mould and cryptococcus

Question 26

How are echinocandins administered?

Answer 26

For systemic infections given parenterally

Question 27

How do 5-fluorocytosines work?

Answer 27

Inhibits RNA/ protein and DNA synthesis

Question 28

what is the spectrum of activity of 5-fluorocytosine?

Answer 28

works on yeasts only e.g.candida and cryptococcus spp.

Question 29

What are the adverse effects of 5-fluorocytosine?

Answer 29

Bone marrow suppression

Question 30

How does griseofulvin work?

Answer 30

Inhibition of fungal mitosis

Question 31

what is griseofulvin used for?

Answer 31

Dermatophyte infection

Question 32

What drugs require therapeutic drug monitoring?

Answer 32

• Itraconazole
• 5-fluorocytosine
• Voriconazole