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Pharm 2 - Exam 4 > Lecture 5 - Antifungals > Flashcards

Lecture 5 - Antifungals Flashcards

1
Q

What are azoles MOA?

A

Inhibit lanosterol from becoming ergosterol which is used like cholesterol in the membrane for stability

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2
Q

Amphotericin B

A

Indications:
Used for serious life threatening systemic mycotic infections because it has the broadest spectrum of action

MOA:
Binds to ergosterol (B for Binds)
Forms artificial membrane pores and leakage of intracellular ions and macromolecules out of the fungal cell
Very broad spectrum of action, fungicidal

Toxicities (all are common):
After infusion:
-chills, fever, muscle spasms, HA, vomiting, hypotension

Longer term:
RENAL DAMAGE

Pregnancy: amphotericin B is preferred to azoles (teratogenic) and caspofungin (embryotoxic)

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3
Q

What is the MOA of amphotericin B?

A

Binds to ergosterol
Forms artificial membrane pores and leakage of intracellular ions and macromolecules out of the fungal cell
Very broad spectrum of action, fungicidal

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4
Q

What toxicities are associated with amphotericin B?

A

After infusion:
Chills, fever, muscle spasms, HA, vomiting, hypotension

Longer term:
RENAL DAMAGE

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5
Q

Can amphotericin B be used in pregnancy?

A

Yes

It is preferred over azoles which are teratogenic and preferred over caspofungin which is embryotoxic

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6
Q

Azole antifungals

A

Synthetic compounds of 2 classes:

  • imidazoles: topical only
  • triazoles: systemic

Broad spectrum

MOA: decrease the synthesis of ergosterol by inhibiting fungal a cytochrome P450 enzyme (14 alpha sterol demethylase)

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7
Q

Fluconazole

A

PO or IV
Best penetration of all azoles into the CSF

Bioavailability is high and therapeutic index is highest of the azoles

Clinical uses:
Drug of choice for cryptococcal meningitis
Drug of choice for prophylaxis

Potent inhibitor of CYP2C9 - phenytoin, warfarin

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8
Q

Itraconazole

A

Poor penetration into CNS

Clinical uses:
Drug of choice for dimorphic fungi histoplasma, blastomyces and sporothrix

Drug induced CHF

Potent inhibitor of CYP3A4 (statins, midazolam, triazolam)

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9
Q

What is the clinical use of itraconazole?

A

Drug of choice for dimorphic fungi histoplasma, blastomyces, and sporothrix

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10
Q

What are SE of itraconazole?

A

Drug induced CHF

CYP3A4 inhibitor

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11
Q

Which azole is the best to use for CSF infections?

A

Fluconazole

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12
Q

Can fluconazole be used in pregnancy?

A

No

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13
Q

What is the indication for fluconazole?

A

Drug of choice for cyptococcal meningitis

Drug of choice for prophylaxis

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14
Q

What is the clinical use for itraconazole?

A

Drug of choice for dimorphic fungi histoplasma, blsatomyces and sporothrix

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15
Q

Voriconazole

A

PO/IV
Broadest spectrum of the 3 on the list

Indications:
Drug of choice for treatment of invasive aspergillosis: better outcomes and less toxicity than amphotericin B

Toxicity:
Visual disturbances common including blurring and changes in color vision or brightness —usually only during the first 30 minutes of dose - reversible

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16
Q

What is the indication for voriconazole?

A

Drug of choice for treatment of invasive aspergillosis: better outcomes and less toxicity than amphotericin B

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17
Q

What toxicity is seen with voriconazole?

A

Visual disturbances common

Include blurring and changes in color vision or brightness - usually only during first 30 min of dose and reversible

18
Q

Caspofungin

A 
Echinocandin (newest class of agents) 
IV

MOA:
Inhibits synthesis of Beta(1-3) glucan (cell wall synthesis inhibitor)
Disrupts the fungal cell wall

Indications:
Limited to aspergillus and candidia sp
Used in invasive aspergilloss in pts not responsive to voriconazole

Toxicity:
Hepatotoxicity (increase in combo with cyclosporine)

19
Q

What is the MOA of caspofungin?

A

Aka echinocandin

Inhibits synthesis of Beta (1-3) glucan (cell wall synthesis inhibitor)
Disrupts the fungal cell wall

20
Q

What is the indication for caspofungin?

A

Limited to aspergillus and candida

Used in invasive aspergillosis in pts not responsive to voricanazole

21
Q

What toxicities are seen with caspofungin?

A

Hepatotoxicity (increased in combo with cyclosporine)

22
Q

Griseofulvin

A

Derived from PCN
MOA:
A mitotic inhibitor (fungistatic)
Interferes with microtubule assembly

Deposited in newly growing keratin of skin and nails

Indication:
For dermatophytosis only
Treatment must persist for almost a year because it doesnt treat the infected nail but prevents the newly forming nail from being infected

Toxicity:
P450 inducer

23
Q

What is the MOA for griseofulvin?

A

A mitotic inhibitor (fungistatic)
Interferes with microtubule assembly

Deposited in newly growing keratin of skin and nails

24
Q

What is the indication for griseofulvin?

A

For dermatophytosis only

Treatment must persist for about a year

25
Q

What are the toxicities seen with griseofulvin?

A

P450 inducer

26
Q

Terbinafine

A

PO
Keratophilic (like griseofulvin), also has direct fungicidal
-only needed for about 3 months

Indications:
Treatment of dermatophytoses, especially onychomycosis (fingernail and toenail infections)

MOA:
Inhibits fungal enzyme (squalene epoxidase) which results in increased levels of squalene which is toxic to the fungus

27
Q

What is the MOA of terbinafine?

A

Inhibits a fungal enzyme (squalene epoxidase) which results in increased levels of squalene which is toxic to the fungus

Only need treatment for 3 months

28
Q

What is the indication for terbinafine?

A

Treatment of dermatophytoses, especially onychomycosis (fingernails and toenail infections)

29
Q

Flucytosine

A

Anti-metabolite

MOA:
In fungal cells, flucytosine is taken up by cytosine permease
Converted to 5-FU by cytosine deaminase
5-FU metabolized to nucelotide that blocks DNA and RNA synthesis

Used only in combinations

Hematoxicity

30
Q

Which antifungal has the best CNS penetration?

A

Fluconazole

31
Q

Which antifungal would you use for a systemic mycotic infection?

A

Amphotericin B

Although cryptococcal meningitis is treated with fluconazole

32
Q

Which antifungal is used for prophylaxis in high risk pts with neutropenia?

A

Fluconazole

33
Q

Of the azoles, which one is no longer approved for IV use?

A

Itraconazole

34
Q

Imidazole vs traizoles

A

Imidazole: topical only

Triazoles: systemic

35
Q

Which fungal treatment has a risk of SJS?

A

Fluconazole

36
Q

What is a major risk factor of amphotericin B?

A

Renal damage

At first its reversible with decreased perfusion and then its irreversible with tubular damage

37
Q

Which azole has the broadest spectrum?

A

Variconazole

38
Q

What is a common side effect seen with variconazole?

A

Visual disturbances

Usually within the first 30 minutes of dose (blurring, color changes)

39
Q

Which antifungal blocks the synthesis of Beta (1-3) glucan?

A

Capsofungin (a echinocandin) newest class of drug

Cell wall synthesis inhibitor

40
Q

Which antifungal can only be used if its used in combination with other drugs?

A

Flucytosine

Narrow spectrum of action

SE: hematotoxicity (anemia, leukopenia)

Pharm 2 - Exam 4 (9 decks)

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