Antifungal Agent

Question 1

What do superficial fungal infections usually affect?

Answer 1

Hair, nails, mucosal membrane and skin

Question 2

What do deep fungal infections affect?

Answer 2

Blood stream, organs and meninges. Most common organism is crypto meningitis which is an opportunistic infection in HIV

Question 3

What fungi is the main cause of superficial fungal infection?

Answer 3

Dermatophytes

Question 4

What is the treatment for superficial fungal infection?

Answer 4

Over the counter topical anti fungal creams, lotions and gels

Most effective is Terbinafine (Lamisile)

Question 5

What are the characteristics of Terbinafine (lamisile)

Answer 5

A synthetic anti fungal
Highly lipophilic in nature
Tends to accumulate in nails skin and fatty tissue
Active against dermatophytes, Molds and dimorphic fungi

Question 6

What are the yeasts most frequently isolated in clinical practice (for deep fungal infections)

Answer 6

Candida species
Cryptococcus species

Question 7

How is cryptococcus species acquired ?

Answer 7

Inhalation
(Pulmonary cryptococcus is asymtomatic but does spread to the meninges and cause meningitis -common in HIV+ and solid organ transplant patients)

Question 8

What does the cell wall of fungi contain?

Answer 8

Chitin
Glucan
Variety of Mano proteins

Question 9

What are the three general mechanisms for anti fungal agents ?

Answer 9

Cell wall disruption
Inhibition of cell division
Inhibition of cell wall formation

Question 10

How do anti fungal agents inhibit cell wall formation?

Answer 10

Target Beta glucan synthesis

Question 11

How do antifungal agents cause cell membrane disruption?

Answer 11

Target ergosterol :
Binding to it to form pores and cause leakage
Inhibiting ergosterol biosynthesis

Question 12

How do antifungal agents inhibit cell division on fungi?

Answer 12

inhibiting DNA transcription

Question 13

Name 4 Antifungal agents for invasive infections

Answer 13

(PEA-5)
Polyenes*
Azoles
Echinocandins
5- flucosytosine

Question 14

What is the mainstay (centrepiece) of treatment for severe fungal infection?

Answer 14

Amphoteric -B (class of Polyene)

Question 15

What is the mode of action of amphoteric- B ?

Answer 15

Binds to the membrane and cause leakage

Question 16

What are the Disadvantages of using amphoteric -B

Answer 16

It must be given IV and is toxic due to nonselective action on cholesterol in mammalian cell membrane

Question 17

What are the side effects of using amphoteric-b?

Answer 17

Occurs in 50-90% of cases (common)
-Nephrotoxicity
-Infusion related (fever, chills, hypotension, muscle spasm, vomiting and headaches )

Question 18

What is used to treat cutaneous or mucocutaneous fungal infection?

Answer 18

Nystatin (class of polyene)

Question 19

What is the MOA for Nystatin?

Answer 19

Binds to ergosterol in the membrane causing leakage

Question 20

What are the first generation Of Triazoles

Answer 20

Fluconazol and Itraconazole

Question 21

What are the second generation Triazoles ?

Answer 21

Vericonazole and Posaconazole
(IS active against Aspergilus )

Question 22

How is Ketoconazole administered ?

Answer 22

As a cream or in a shampoo

Question 23

How is Itraconazole administered?

Answer 23

Taken orally in a capsule (can be used to treat infection of the nails)
(Common used is Sporanox)

Question 24

Which drug inhibits both DNA synthesis and proteins synthesis in the fungal cell?

Answer 24

Flucocytosine