Antifungals Flashcards

1
Q

Which two opportunistic fungal infections will be molds in the body?

A

Aspergillosis and Mucormycosis (there are no butterflies in either Sketch)

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2
Q

Although Aspergillus is found predominately in immunocompromised people, it is not found in those with HIV. Why?

A

Neutrophils can kill Aspergillus, so typically it occurs in people who are granulocytopenic.

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3
Q

Describe the structure of the fungal cell wall from outside to inside.

A
Outer surface 
• Mannoproteins
•Beta-1,3-glucan 
•Chitin
•Phospholipid bilayer with ergosterol
Inner surface
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4
Q

The name amphotericin can help you remember its chemical properties: _______________.

A

it is amphipathic, with a nonpolar and polar section

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5
Q

How exactly does amphotericin work?

A

It binds to the hydrophobic portion of ergosterol and then the hydrophilic portion of amphotericin makes a pore that destroys the membrane gradient.

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6
Q

Why can’t amphotericin be orally absorbed?

A

It has a large hydrophobic region and will not dissolve well.

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7
Q

Amphotericin can be administered two ways: ________________.

A

intravenously or intrathecally

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8
Q

Patients are often premedicated with _______________ to eliminate the adverse infusion reactions.

A

acetaminophen or hydrocortisone

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9
Q

Although amphotericin is occasionally used for ____________, there are newer drugs that are more effective.

A

Candida

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10
Q

True or false: amphotericin works synergistically with the azoles.

A

False. Azoles inhibit the synthesis of ergosterol and amphotericin relies on ergosterol to be fungicidal, so it wouldn’t make sense to co-administer them.

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11
Q

The newer azoles are of the _____________ type.

A

triazole

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12
Q

How do fungi become resistant to the azoles?

A

They can develop efflux pumps or point mutations in CYP.

Think of a bike pump on the road to Oz.

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13
Q

The azoles are good for _____________ because they are orally available.

A

outpatient treatment

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14
Q

Which azole can reach the CSF?

A

Fluconazole (like the flying monkey with the helmet)

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15
Q

Ketoconazole has what two side effects?

A

Gynecomastia and GI upset

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16
Q

Fluconazole has what side effects?

A

GI upset, teratogen, and drug interactions

17
Q

How is fluconazole metabolized?

A

Renally (with a long half-life of 25 hours)

Note: all other azoles are hepatically metabolized.

18
Q

Voriconazole has what unique side effects?

A

Visual changes: loss of color vision; flashes of light

19
Q

______________ are now used as empiric therapy for fungal septicemia in the immunosuppressed.

A

The echinocandins

20
Q

The echinocandins must be given _________________.

A

intravenously

21
Q

The dose of echinocandins must be altered in those with _____________ insufficiency.

A

hepatic

22
Q

Echinocandins cause what side effects?

A

GI upset, skin rashes, and headache (relatively safe overall)

23
Q

What antifungal is given as a prodrug that requires intracellular activation?

A

Flucytosine, which must be activated by cytosine deaminase

24
Q

How is flucytosine administered?

A

Orally

25
Q

______________, in addition to fluconazole, also distributes to the CSF.

A

Flucytosine

Just remember that the FLUs FLY to the CSF.

26
Q

True or false: amphotericin B is commonly given to pregnant women.

A

True! It’s one of the only antifungals shown to be safe in pregnancy.

27
Q

Describe the distribution of griseofulvin.

A

It is not absorbed well orally because it requires lots of fat, but because it accumulates in keratin-containing tissues it can be given orally for skin and nail infections.

28
Q

What are the side effects of griseofulvin?

A

Headache and CYP induction

29
Q

Which antifungals are fungicidal and fungistatic?

A

•Fungicidal:

  • Amphotericin
  • Terbinafine
  • Echinocandins
  • Nystatin

•Fungistatic:

  • Griseofulvin
  • Azoles

Flucytosine –not stated in the handout

30
Q

Amphotericin must be dose-limited in patients with _____________.

A

renal impairment

31
Q

True or false: IV nystatin can treat esophageal candidiasis.

A

False. Because of its toxicity, nystatin is limited to topical and oral treatment. It is poorly absorbed, so oral use does not lead to toxicity.

32
Q

Sketchy left an important side effect out of the azoles scene: ________________.

A

they are teratogens

33
Q

The echinocandins cannot be used to treat ______________.

A

CSF infections

34
Q

Which is absorbed better, terbinafine or griseofulvin?

A

Terbinafine

35
Q

Newer azoles can be used for ______________.

A

mucormycosis