Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Personal Deck > Antifungals > Flashcards

Antifungals Flashcards

1
Q

What are the two groups of antifungals required for this course?

A

Azoles & Allylamines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the four azole’s required for the course?

A

Fluconazole, Itraconazole, Voriconazole, Ketoconazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the main Allylamine required for the course?

A

Terbinafine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the unique component in fungal cell walls targeted by antifungals?

A

cholesterol ergosterol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the MOA of azoles?

A

Reduce ergosterol production by inhibiting 14-Ademethylase (the fungal CYP450 enzyme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which major enzyme group is inhibited by the azoles?

A

CYP450

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the MOA of Allylamines?

A

They interfere with synthesis of ergosterol through inhibition of squalene epoxide → squalene builds up and causes cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the main organisms targeted by azoles?

A

-Candida

-Cryptococcus

-Mycoses: blastomycosis, coccidioidomycosis, histoplasmosis

-Dermatophytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Use of Itraconazole is now limited to combat these organisms:

A

histoplasmosis & blastomycosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Voriconazole has an extended spectrum of coverage & is used to treat:

A

Most yeasts & molds including fluconazole resistant Candida, Aspergillus and Zygomyces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Terbinafine is only approved for the treatment of:

A

Onychomycosis (fungal infection under nails)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe Fluconazole’s absorption & distribution:

A

Well absorbed with a bioavailability of 90%. Wide distribution into CSF, eye, & perineum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Itraconazole can be taken as a capsule or solution. which one is preferred and why?

A

Solution is preferred because bioavailability not affected by food or antacids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe the PO absorption of Itraconazole

A

Capsule bioavailability is 55% when taken with food; 30% on empty stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What instructions should be given to a patient when taking PO Itraconazole?

A

DO NOT TAKE with H2 Blockers or PPI’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the distribution of Itraconazole?

A

Higher distribution to tissues than plasma. Does not enter CSF; enters breast milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is Voriconazole’s absorption?

A

Bioavailability of 90% in adults; 45-64% in children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is Ketoconazole’s absorption?

A

99% protein bound. 75% bioavailability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe Terbinafine’s absorption & distribution?

A

-Bioavailability 70-85%; not affected by food
-Lipophilic & widely distributed: outer layers of skin, hair follicles, skin & nails

Enters breast milk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe fluconazole’s metabolism:

A

Inhibits CYP3A4 & 2C9 (BUT, less than the other antifungals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Describe fluconazole’s excretion:

A

Heavy renal excretion (80% as unchanged drug, ~11% as metabolite)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which parameters should be taken into account before prescribing fluconazole?

A

Renal impairment; dose adjustment (reduce by 50%) required when CrCl <50mL/min

23
Q

Describe Itraconazole’s metabolism

A

Extensive metabolism & inhibition of CYP3A4

24
Q

How is Itraconazole excreted?

A

40% in urine as metabolites; 3-18% in feces

25
Q

Describe Voriconazole’s metabolism:

A

Extensive metabolism by CYP450

26
Q

What is a special consideration for some patients taking Voriconazole?

A

Dose should be adjusted for patients who are poor metabolizers of CYP2C19

27
Q

How is Voriconazole excreted?

A

almost entirely non-renal

28
Q

How is Ketoconazole metabolized?

A

Very strong CYP3A4 inhibitor

29
Q

How is Ketoconazole excreted?

A

85-90% in bile & feces; 10-15% in urine

30
Q

What is unique about Terbinafine’s metabolism?

A

Undergoes extensive first pass metabolism & CYP450 only does about 5% of metabolism

31
Q

Is Terbinafine affected by drugs that undergo CYP450 metabolism?

A

No; CYP450 only does about 5% of metabolism

32
Q

What are important considerations when prescribing Terbinafine?

A

Requires dose reduction in liver & renal impairment

33
Q

How is Terbinafine excreted?

A

80% in urine as metabolites; 20% in feces

34
Q

Describe the blackbox warning for Ketoconazole:

A

Can cause severe hepatotoxicity that can lead to death or liver transplant; only use this medication if other anti fungal therapies are available

35
Q

What are general precaution for the azoles & allylamines?

A

-All have been associated with hepatotoxicity
-Caution in preexisting liver & renal disease

36
Q

Which antifungals are excreted in breast milk?

A

Fluconazole
Itraconazole
Terbinafine

37
Q

Is Voriconazole safe to use in pregnancy?

A

It should only be used in pregnancy when potential benefits to mom outweigh risk to fetus

38
Q

Can Voriconazole be used in children?

A

Yes. May be used in neonates with severe fungal infection; higher doses may be required in children <50kg or less than 15 years old

39
Q

Can Fluconazole be used in children?

A

Yes. Safe & effective for children & infants

40
Q

What are common ADR’s for Azoles?

A

May cause QT prolongation

41
Q

Itraconazole should be used with caution in these patients:

A

patients with preexisting HF & ventricular dysfunction; has been Rarely associated with development of HF

42
Q

ADR for Voriconazole:

A

Visual disturbances in 19% of patients:
-Flashes of light, photophobia, color changes
-Neurological symptoms (associated with toxic drug levels)
Visual hallucinations, confusion, myoclonus

43
Q

How can you assume a patient has toxic drug levels of Voriconazole?

A

They would experience neurological symptoms such as
visual hallucinations, confusion, myoclonus

44
Q

ADR’s for Ketoconazole:

A

PO tablets may cause hepatotoxicity leading to death

45
Q

ADR’s for Terbinafine:

A

-Hepatoxocity
-Loss or change of taste (can require 2-6 months to recover)
-Hypersensitivity, hepatitis, blood dyscrasias, Steven Johnson’s

46
Q

To a general extent, we could state that all antifungals inhibit:

A

CYP3A4

47
Q

Ketoconazole should not be used with these medications:

A

-Rifampin, Isoniazid
-Hepatotoxic drugs
-Drugs that increase gastric pH (antacids, PPI’s, H-2 Blockers)

48
Q

Fluconazole should not be used concurrently with these meds:

A

Cimetidine & Hydrochlorothiazides

49
Q

These drugs are contraindicated when taking voriconazole:

A

Carbamazepine, Rifamycin, St. John’s Worth, Ergot Alkaloids, Rifabutin, Sirolimus

50
Q

Which drugs are contraindicated when taking Terbinafine?

A

alcohol, hepatotoxins

51
Q

We should avoid concurrent use of these drugs when taking Terbinafine:

A

phenytoin, rifampin

52
Q

What are indications for fluconazole?

A

-candidiasis (vaginal, oropharyngeal, esophageal)
-other candida infections

53
Q

What is voriconazole indicated for?

A

Invasive aspergillosis

54
Q

What is Terbinafine indicated for?

A

Onychomycosis (toenail & fingernail)
Off label: Tinea: capitis, corporis or cruris, pedis

Personal Deck (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions