Antifungal Drugs

Question 1

What is the classification of Amphotericin B?

Answer 1

Polyene antibiotic
Systemic use
anti fungal

Question 2

What is the mechanism of action of Amphotericin B?

Answer 2

Binds selectively to ergosterol, which alters permeability of cell by forming pores in cell membrane, results in the loss of intracellular ions + macromolecules which leads to cell death.

Question 3

What are the therapeutic indications of Amphotericin B?

Answer 3

most organisms responsible for systemic mycoses

Question 4

What is the solubility of Amphotericin B?

Answer 4

soluble in water

Question 5

How is Amphotericin B administered?

Answer 5

IV, oral for candidiasis infections within the lumen of GIT, topically

Question 6

What are the 2 formulations of Amphotericin B?

Answer 6

• colloidal suspension of amphotericin B and sodium deoxycholate (IV)
• amphotericin complexed with lipids or encapsulated in liposomes

Question 7

What % of Amphotericin B is bound to plasma proteins?

Answer 7

> 90%

Question 8

Describe the distribution of Amphotericin B

Answer 8

widely distributed in tissues, crosses BBB poorly (except when meninges are inflamed)

Question 9

What is the half-life of Amphotericin B?

Answer 9

24-hours, up to 15 days with repeated dosages

Question 10

How is Amphotericin B excreted?

Answer 10

excreted very slowly via the urine, 2-5% in an active form

Question 11

What are the adverse effects of Amphotericin B?

Answer 11

• fever, headache, tinnitis, nausea
  and vomiting and chills (immediate)
• renal toxicity (slower)

Question 12

What is the classification of Ketoconazole?

Answer 12

Imidazole
Systemic use
anti fungal

Question 13

What is the mechanism of action of Ketoconazole?

Answer 13

inhibits of the cytochrome P450 enzyme system of fungal cells

Question 14

What are the therapeutic indications of Ketoconazole?

Answer 14

yeast and dermatophyte infections

Question 15

Describe the absorption of Ketoconazole

Answer 15

Oral absorption (varies among individuals)

Question 16

What % of Ketoconazole is bound to plasma proteins?

Answer 16

99%

Question 17

Describe the distribution of Ketoconazole

Answer 17

widely distributed in tissues and body fluids

Question 18

What is the half-life of Ketoconazole?

Answer 18

8 hours

Question 19

How is Ketoconazole metabolised and excreted?

Answer 19

metabolized in the liver and excreted in bile, a small amount is also excreted in urine

Question 20

What are the adverse effects of Ketoconazole?

Answer 20

• fatal liver damage
• gynecomastia, infertility, and menstrual irregularities
• alters metabolism of other drugs (increases concentration and toxic effects)

Question 21

What is the classification of Fluconazole?

Answer 21

Triazole
Systemic use
Antifungal

Question 22

What is the mechanism of action of Fluconazole?

Answer 22

inhibits of the cytochrome P450 enzyme system of fungal cells

Question 23

What are the therapeutic indications of Fluconazole?

Answer 23

• Orally: oropharyngeal and eosophageal candidiasis
• IV: systemic candidiasis and cryptococcal infections including cryptococcal meningitis
• Mainly candida and cryptococcus

Question 24

How is Fluconazole administered?

Answer 24

Orally and IV

Question 25

Describe the distribution of Fluconazole

Answer 25

Crosses BBB

Question 26

What are the adverse effects of Fluconazole? (5)

Answer 26

- nausea - vomiting - abdominal pain - diarrhea - headache

Question 27

What is the classification of Griseofulvin?

Answer 27

Antibiotic Systemic use antifungal

Question 28

What is the mechanism of action of Griseofulvin?

Answer 28

inhibits mitosis in fungal cells by binding to tubulin

Question 29

What are the therapeutic indication of Griseofulvin?

Answer 29

dermatophyte (micosporum) infections of the skin, hair and nails - fungistatic - fungicidal

Question 30

What is the spectrum of activity of Griseofulvin?

Answer 30

narrow

Question 31

How is Griseofulvin administered?

Answer 31

orally

Question 32

Describe the absorption of Griseofulvin

Answer 32

poorly soluble in water and absorption is improved when the agent is taken with a fatty meal

Question 33

What is the half life of Griseofulvin?

Answer 33

24 hours, detectable in the skin for longer

Question 34

What are the adverse effects of Griseofulvin?

Answer 34

- GIT disturbances - headache - photosensitivity - induces cytochrome P450 enzymes (causes drug interactions)

Question 35

What is the classification of Nystatin?

Answer 35

Polyene antibiotic topical use anti fungal

Question 36

What is the classification of Clotrimazole?

Answer 36

Topical Use Imidazoles anti fungal