Antifungals Flashcards

1
Q

Moa of amphotericin B

A

Amphotericin B binds to ergosterol in the plasma membranes of sensitive fungal cells -form pores - pores disrupt membrane function, allowing electrolytes (particularly potassium) and small molecules to leak from the cell, resulting in cell death

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2
Q

Antifungal spectrum of amphotericin B

A
effective against a wide range of fungi: Candida albicans
 Histoplasma  capsulatum
Cryptococcus  neoformans
Coccidioides  immitis
Blastomyces  dermatitidis
and many strains of  Aspergillus
protozoal infection leishmaniasis
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3
Q

Elimination of amphotericinB

A

Some via bile

Some in urine

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4
Q

Csf penetration of amphotericin B

A

Minimal penetration in CSF

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5
Q

Method of administration of amphotericin

A

topical

IV-
conventional( soadium deoxycholate)

Liposomal preparation( less infusion and renal toxicity)

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6
Q

adverse effects of amphotericin

A

ACUTE
Fever and chills
Thrombophlebitis

CHRONIC
Renal impairment: more if given with other nephrotoxic drugs
Hypokalemia: caution in digoxin
Anemia: BM depression

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7
Q

Moa of flucytosine

A

Combined with amphotericjn which increases its entry into cell by making it more permeable.

Flucyosine- 5 florouracil - 5 FdUMP which inhibits thymidylate synthase depriving the cell of nucleotide

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8
Q

Adr of flucytosine

A

BM depression

Hepatic dysfxn

Git: n/v/d

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9
Q

Excretion of 5FC

A

Urine

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10
Q

2 different classes of azole antifungals

A

Imidazoles : cutaneous ds

Troazoles : cutaneous and systemic ds

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11
Q

Moa of azoles

A

block the demethylation of lanosterol to ergosterol, the principal sterol of fungal membranes disrupting membrane structure and function.

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12
Q

All azoles _____ hepatic CYP450 3A4 isoenzymes to varying degrees

A

INHIBIT

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13
Q

CI of azoles

A

Pregnancy: teratogenic

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14
Q

Fluconazole use

A

CRYPTOCOCCUS NEOFORMANS

CANDIDA

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15
Q

Adr of fluconazole

A

n/v ,headache, and skin rashes Hepatotoxicity

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16
Q

Adr of itraconazole

A
n/v,  rash
hypokalemia
hypertension
edema, headache
Hepatotoxicity 
Itraconazole  has a negative inotropic effect  and  should  be  avoided  in  patients  with  evidence  of  ventricular dysfunction, such as heart failure.
17
Q

Itraconazole use

A
Broad spectrum
drug of choice for the treatment of blastomycosis
sporotrichosis
paracoccidioidomycosis
 histoplasmosis
18
Q

Hepatoxicity os common to which class of antifungals

A

Azoles

19
Q

Posaconazole use

A

Candida
Aspergillus
Zygomycetes

20
Q

Voriconazole use

A

Broad spectrum

Doc for invasive Aspergillosis

21
Q

All azole inhibit CYP 450 isoenzymes

All azole are hepatotoxic

A

Yes

Yes

22
Q
Primary route of elimination of 
Flu
Itra
Vori
Posa
A

Renal

Rest Hepatic

23
Q

Echinocandins

A

Moa: interfere with synthesis of fungal cell wall leading to lysis of cell

Use: candida , aspergillus (little against others)

Eg: caspofungin , micafungin , anidulafungin

24
Q

Antifungal for Tinea capitis and unguim

Oral / topical

A

Oral

25
Q

Moa of squalene oxidase inhibitors

A

These agents act by inhibiting squalene epoxidase, thereby blocking the biosynthesis of ergosterol, an essential component of the fungal cell membrane

26
Q

Squalene oxidase inhibitors eg

A

Terbrnafine
Naftifine
Butenafine

27
Q

Kinetics of terbenafine

A

Oral terbinafine is extensively metabolized by several CYP450 isoenzymes and is excreted mainly via the urine . The drug should be avoided in patients with moderate to severe renal impairment or hepatic dysfunction.

28
Q

Adberse effects of terbenafine

A

gastrointestinal disturbances (diarrhea, dyspepsia, and nausea), headache, and rash.

Taste and visual disturbances

transient elevations in serum hepatic transaminases.

Terbinafine is an inhibitor of the CYP450 2D6 isoenzyme, and concomitant use with substrates of that isoenzyme may result in an increased risk of adverse effects with those agents.

29
Q

Moa of griseofulvin

A

causes disruption of the mitotic spindle and inhibition of fungal mitosis

30
Q

Polyene antifungals

A

Amphotericin B

Nystatin

31
Q

Use of nystatin

A

cutaneous and oral Candida infections.

The drug is negligibly absorbed from the gastrointestinal tract, and it is not used parenterally.

It is administered as an oral agent for the treatment of oropharyngeal candidiasis (thrush), intravaginally for vulvovaginal candidiasis, or topically for cutaneous candidiasis.

32
Q

Imidazoles

A
butoconazole 
 clotrimazole 
econazole
ketoconazole
 miconazole
oxiconazole
 sertaconazole
 sulconazole
33
Q

Moa of various antifungals

A

Echinocandins: inhibit cell wall

Azoles : inhibit cell membrane

Polyenes : inhibit cell membrane

Griseofulvin : mitotic spindle hence mitosos

Flucytosine: DNA synthsis