Antifungal agents

Question 1

What are dermatophytes?

Answer 1

Fungal infections of the epidermis and integuments (hair and nails)

Question 2

Treatment for dermatophytes?

Answer 2

Topical antifungals such as clotrimazole or terbinafine

Question 3

Do onychomycoses require topical or systemic treatment?

Answer 3

systemic

Question 4

What systemic antifungals can treat onychomychosis?

Answer 4

Itraconazole, terbinafine

Question 5

Treatment for candida infections?

Answer 5

Clotrimazole or nystatin topical

Fluconazole PO if no response

Question 6

What are the common systemic fungal infections?

Answer 6

Blastomycosis, Coccidioidomycosis, Cryptococcosis, Histoplasmosis

Question 7

General treatment of systemic fungal infections?

Answer 7

Amphotericin B infusions

Question 8

Who is at risk for opportunistic infections?

Answer 8

Anyone after use of broad spectrum antibiotics
Immunosuppressed patients
Patients with systemic disease

Question 9

What are 3 pathogens of opportunistic infections and first line treatments?

Answer 9

Candidiasis - fluconazole
Aspergillosis - amphotericin B
Pneumocystis pneumonia - TMP-SMX

Question 10

Mechanism of action of amphotericin B?

Answer 10

Binds ergosterol in fungal membrane, which opens pores and leads to leakage of cell constituents.

Question 11

T/F? Amphotericin B is highly selectively toxic.

Answer 11

False - it also binds to cholesterol components in mammalian cells

Question 12

What is the major limiting factor of amphotericin B infusions?

Answer 12

Nephrotoxicity.

Question 13

Most common adverse reaction to amphotericin B?

Answer 13

Anemia - 75%

Question 14

Mechanism of action of nystatin?

Answer 14

Same as amphotericin B.

Question 15

Is nystatin topical or IV?

Answer 15

Topical only

Question 16

What are the echinocandins?

Answer 16

Micafungin and anidulafungin

Question 17

Mechanism of action of echinocandins?

Answer 17

Inhibits essential component (Beta (1,3)-D-glucan) of fungal cell walls

Question 18

Echinocandins more or less toxic than amphotericin B?

Answer 18

Less, because mammalian cells do not have that component

Question 19

Uses of echinocandins?

Answer 19

Treatment of aspergillosis in patients refractory to amphotericin B or itraconazole.

Question 20

Adverse effects of echinocandins?

Answer 20

Histamine mediated symptoms

fever, N/V, headache

Question 21

What are the triazoles and their mechanism of action?

Answer 21

Fluconazole, itraconazole

Selective inhibition of fungal cytochrome P450

Question 22

Clinical uses of fluconazole?

Answer 22

Vaginal candidiasis if topical treatment fails, oropharyngeal and esophageal candidiasis
Also initial treatment for cryptococcal meningitis

Question 23

Clinical uses for itraconazole?

Answer 23

Systemic therapy for dermatophytoses, 2nd line for onychomycosis

Question 24

Excretion of triazoles?

Answer 24

Fluconazole - renal

Itraconazole - hepatic

Question 25

Adverse reactions of triazoles?

Answer 25

Generally well tolerated

Can cause DDIs due to inhibition of CYP450

Question 26

What are the imidazoles?

Answer 26

ketoconazole, clotrimazole, miconazole

Question 27

Mechanism of action for imadazoles?

Answer 27

Inhibits P450 dependent enzyme 14 alpha demethylase

Question 28

Clinical uses of imidazoles?

Answer 28

Oral and vaginal candidiasis

Question 29

Mechanism of terbinafine?

Answer 29

Inhibits squalene oxidase.

Question 30

Terbinafine fungicidal or fungistatic?

Answer 30

fungicidal

Question 31

Clinical uses of terbinafine?

Answer 31

Onychomycosis

Question 32

Adverse reactions to terbinafine?

Answer 32

Inhibition of CYP450 drug metabolism