Antifungal agents Flashcards

1
Q

What are dermatophytes?

A

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

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2
Q

Treatment for dermatophytes?

A

Topical antifungals such as clotrimazole or terbinafine

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3
Q

Do onychomycoses require topical or systemic treatment?

A

systemic

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4
Q

What systemic antifungals can treat onychomychosis?

A

Itraconazole, terbinafine

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5
Q

Treatment for candida infections?

A

Clotrimazole or nystatin topical

Fluconazole PO if no response

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6
Q

What are the common systemic fungal infections?

A

Blastomycosis, Coccidioidomycosis, Cryptococcosis, Histoplasmosis

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7
Q

General treatment of systemic fungal infections?

A

Amphotericin B infusions

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8
Q

Who is at risk for opportunistic infections?

A

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

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9
Q

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

A

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

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10
Q

Mechanism of action of amphotericin B?

A

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

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11
Q

T/F? Amphotericin B is highly selectively toxic.

A

False - it also binds to cholesterol components in mammalian cells

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12
Q

What is the major limiting factor of amphotericin B infusions?

A

Nephrotoxicity.

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13
Q

Most common adverse reaction to amphotericin B?

A

Anemia - 75%

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14
Q

Mechanism of action of nystatin?

A

Same as amphotericin B.

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15
Q

Is nystatin topical or IV?

A

Topical only

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16
Q

What are the echinocandins?

A

Micafungin and anidulafungin

17
Q

Mechanism of action of echinocandins?

A

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

18
Q

Echinocandins more or less toxic than amphotericin B?

A

Less, because mammalian cells do not have that component

19
Q

Uses of echinocandins?

A

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

20
Q

Adverse effects of echinocandins?

A

Histamine mediated symptoms

fever, N/V, headache

21
Q

What are the triazoles and their mechanism of action?

A

Fluconazole, itraconazole

Selective inhibition of fungal cytochrome P450

22
Q

Clinical uses of fluconazole?

A

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

23
Q

Clinical uses for itraconazole?

A

Systemic therapy for dermatophytoses, 2nd line for onychomycosis

24
Q

Excretion of triazoles?

A

Fluconazole - renal

Itraconazole - hepatic

25
Adverse reactions of triazoles?
Generally well tolerated | Can cause DDIs due to inhibition of CYP450
26
What are the imidazoles?
ketoconazole, clotrimazole, miconazole
27
Mechanism of action for imadazoles?
Inhibits P450 dependent enzyme 14 alpha demethylase
28
Clinical uses of imidazoles?
Oral and vaginal candidiasis
29
Mechanism of terbinafine?
Inhibits squalene oxidase.
30
Terbinafine fungicidal or fungistatic?
fungicidal
31
Clinical uses of terbinafine?
Onychomycosis
32
Adverse reactions to terbinafine?
Inhibition of CYP450 drug metabolism