Anti-fungals

Question 1

How do fungi grow?

Answer 1

As single celled (yeasts) or filamentous multicellular aggregates (molds)

Question 2

How do yeastlike fungi reproduce?

Answer 2

Budding

Question 3

What does dimorphic fungi mean?

Answer 3

Fungi can grow as yeasts or as molds

Question 4

Dimorphic fungi grow as what in host at what in room temp?

Answer 4

Yeast in host

Mold at room temp

Question 5

Fungi that are pathogenic in humans are what?

Answer 5

Nonmotile and have a rigid cell well

Question 6

The cell wall in pathogenic fungi are composed of what?

Answer 6

Chitin and polysaccharides

Question 7

Fungi that are transmissible?

Answer 7

Ringworm of the scalp

Thrush in newborns

Question 8

What are dermatomycoses?

Answer 8

Filamentous fungi that live on keratinized tissue

Question 9

Onychomycoses?

Answer 9

Fungal infection of the nail

Question 10

How does Tolnaftate function?

Answer 10

Inhibits fungal squalene epoxidase resulting in decreased ergosterol

Question 11

What does ergosterol do in fungi?

Answer 11

Steroid in fungal cell membranes

Question 12

Why does Tolnaftate not affect humans?

Answer 12

We use cholesterol as steroid in membranes

Question 13

How does Clotrimazole work?

Answer 13

Inhibit CYP450 which catalyzes 14a-demethylation of lanosterol to ergosterol

Question 14

How do azaleas affect humans?

Answer 14

They have a greater affinity for fungal CYP450s but still get humans so they can interfere with drug metabolism

Question 15

Griseofulvin natural product of whaT?

Answer 15

Penicillium griseofulvin

Question 16

How does Griseofulvin work?

Answer 16

Disrupts mitotic spindle by binding to polymerized microtubules to inhibit mitosis

Question 17

Griseofulvin treats what?

Answer 17

Fungal nail infections, treatment can last a year, taken with high fat diet

Question 18

Amphotericin B is amphoteric, what does that mean?

Answer 18

Has both acidic and basic groups

Question 19

How do you give Ampho B?

Answer 19

IV due to poor GI absorption due to poor water solubility

Question 20

How does Ampho B work?

Answer 20

Binding to ergosterol in membranes, pores open, ions and organic molecules leak out

Question 21

How does 5-Fluorocytosine work?

Answer 21

Fungi convert 5-Fluorocytosine to 5-fluorouracil which is converted into 5-fluorodeoxyuridine monophosphate which inhibits thymidylate synthase

Question 22

What does inhibiting thymidylate synthase do?

Answer 22

Inhibits DNA synthesis

Question 23

In addition to DNA synthesis what else does 5-fluorouracil inhibit?

Answer 23

protein synthesis via incorporation into RNA in place of uracil due to van der Waals radius similarity to hydrogen

Question 24

If used in humans by itself what is 5-fluorouracil used as?

Answer 24

Anticancer agent

Question 25

Why doesn't 5-fluorouracil harm humans?

Answer 25

Human cells have little or no cytosine deaminase activity

Question 26

5-fluorocytosine used with what can treat systemic Candida and Cryptococcus neoformans meningitis?

Answer 26

Ampho B

Question 27

What is 5-fluorocytosine combined with to kill resistant strains

Answer 27

Ampho B

Question 28

How does the combo of 5-Fluorocytosine and Ampho B work?

Answer 28

Ampho B enhances uptake of 5-fluorocytosine

Question 29

Danger of 5-fluorocytosine?

Answer 29

Depresses bone marrow function so don't give to people with bone marrow depression or bad kidneys due to renal excretion

Question 30

Anti fungal used for systemic infections but weaker than Ampho B?

Answer 30

Ketaconazole

Question 31

Distinguishing point about Fluconazole?

Answer 31

3 nitrogen in rings

Question 32

Use for Fluconazole?

Answer 32

Treatment of meningitis from fungi

Question 33

Biggest danger of Fluconazole

Answer 33

Hepatotoxicity

Question 34

Distinguishing feature of Itraconazole?

Answer 34

1:1:1:1 racemic mixture of four diastereomers | 3 nitrogen rings

Question 35

What do you use Itraconazole for?

Answer 35

Histoplasmosis

Question 36

Danger of Itraconazole?

Answer 36

Heart failure so don't give to cardiac patients | Liver failure

Question 37

Itraconazole will interact with what other drugs?

Answer 37

Those metabolizes by CYP450

Question 38

How do Echinocandins work?

Answer 38

Inhibit 1,3-B glucan synthesis in fungal cell walls via noncompetitive inhibition of 1,3-B-glucan synthase

Question 39

Why do Echinocandins not harm humans?

Answer 39

Mammalian cells lack 1,3B-glucan synthase

Question 40

Cross resistance of Echinocandins?

Answer 40

None

Question 41

What does Echinocandins synergistic with?

Answer 41

Voriconazole and ampho B