Fungal IV

Question 1

What kind of centre do echinocandins have?

Answer 1

Cyclic

Question 2

What is the mode of action of echinocandins?

Answer 2

Inhibition of glucan synthase - binds to Fks1p subunit and blocks beta1,3-D-glucan synthesis. This form of gluten gives the cell wall rigidity and so if it is lost the cell wall becomes weakened. Humans don’t have cell walls

Question 3

What do all echinocandins have activity against?

Answer 3

Aspergillis and candida

Question 4

What do echinocandins have no activity against?

Answer 4

Cryptococcus, mucoraceous moulds and dimorphic moulds

Question 5

What are the three types of echinocandins?

Answer 5

Caspofungi, Anidulafungin, Micafungin

Question 6

What is micafungins licence?

Answer 6

Entirely candidacies

Question 7

Which drug can be used for empiric therapy?

Answer 7

Caspofungin

Question 8

What form are all the echinocandins in?

Answer 8

IV as they are very large

Question 9

Which is less toxic, caspofungin or amphotericin B?

Answer 9

Caspofungin

Question 10

How are echinocandins metabolised?

Answer 10

Undergo spontaneous breakdown in tissues and are broken up by peptidases

Question 11

Which drug can cause a loss of potassium?

Answer 11

Caspofungin

Question 12

Which drugs can cause mild deranged liver functions?

Answer 12

Caspofungin and Micafungin

Question 13

Why is C.albican resistant?

Answer 13

Mutations in gene for Fks1p gene of beta1,3-D gluten synthase complex
Particularly codon 645 Ser to Pro, Tyr, Phe

Question 14

Why is C.glabrata resistant?

Answer 14

Mutations in Fks1p and 2 genes associated with echinocandin resistance

Question 15

Why is cryptococcus not susceptible?

Answer 15

Gluten synthase is altered

Question 16

When does up regulation in chitin concentration occur?

Answer 16

When candida species grown in presence of caspofungin at concentration below the MIC

Question 17

What class is terbinafine drugs?

Answer 17

Allylamine class

Question 18

What is the mode of action for terbinafine?

Answer 18

Inhibition of squalene epoxidase

Question 19

What are the formulations of terbinafine?

Answer 19

Tablets, gel, cream and spray

Question 20

How much terbinafine is bioavailable?

Answer 20

45% and heavily protein bound

Question 21

Where are high concentrations of terbinafine is seen in?

Answer 21

Skin and nail

Question 22

How is terbinafine eliminated?

Answer 22

80% urine and 20% faeces

Question 23

What toxicity can terbinafine cause?

Answer 23

Liver deregulation and altered taste perception