Brainscape's Knowledge GenomeTM

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


See full index

General Pharmacology 2 > Antifungals > Flashcards

Antifungals Flashcards

1
Q

Amphotericin B

A
  • Product of Streptomyces nodosus
    • discovered in soil fro Venezuela
  • Amphoteric Polyene Macrolide
  • Poorly soluble in Water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Amphotericin B:

MOA

A
  • Binds to ergosterol in cell wall
  • Increasing permeability leading to fungal death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Amphotericin B:

Adverse Effects:

A

Dose limiting nephrotoxicity

Tremors

Vomiting

Pyrexia

Anorexia

Phlebitis

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

Nephrotoxicity

A

Dose dependent and cumulative

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

Amphotericin B:

Pharmacokenetics

A
  • Poor Oral biovailability
    • parenternal administration for systemic effect
  • Poor Penetration of CNS and Viterous Humor
  • Good Penetration to aqueous humor
  • Long Half Life:
    • ~24hrs in people, EOD
  • Given IV
  • Primarily eliminated by hepatic metabolism
    • small amounts eliminated in urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Amphotericin B:

Sprectrum

A

Broad

  • Fungal and Yeasts:
    • blastomyces
    • Histoplasma
    • Cryptococcus
    • Coccidioides
    • Candida
    • Aspergillus
  • Protazoal:
    • Leishmania
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Amphotericin B:

Uses

A
  • Dogs / Cats
    • Severe systemic diseases, typically followed by oral azoles if initial response
      • 20kg dog, cost ~ $10 dose for 8-16 doses
  • Horses:
    • Systemic disease non-responsive to fluconazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

-Azoles

A

Synthetic Antifungals Including:

Ketoconazole

Itraconazole

Fluconazole

Voriconazole

Miconazole **

Clotrimazole **

** topical use only

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

-Azoles:

MOA

A

Reduce ergosterol synthesis by inhibiting fungal cytochrome P450 (CYP) enzymes

Greater affinity for fungal enzymes compared to mammalian enzymes

Effect: Cell wall damage, Increased permeability, death

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

-Azoles:

Spectrum

A

Broad

some specific drug differences

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

-Azoles:

Resistance:

Intrinsic

A

Organism was not susceptible to the drug to start with

Aspergillus resistance to fluconazole

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

-Azoles:

Resistance:

Acquired

A

Organism was susceptible originally, but over time the organisms became resistant to the drug

Aspergillus resistance to Ketoconazole

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

-Azoles:

Adverse Effects

A

Nausea

Anorexia

Vomiting

Hepatotoxicity

CYP inhibition

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

Ketoconazole:

A
  • Replaced amphotericin B for many indications when introduced due to lowe toxicity
    • however resistance has occurred, newer drugs have replaced ketoconazole for many uses
    • NOT used in horses
      • poor oral bioavailability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ketoconazole:

Spectrum

A

Broad

  • Fungal and Yeasts:
    • Blastomyces
    • Histoplasma
    • Cryptococcus
    • Coccidioides
    • Candida
    • Malassezia
    • Dermatophytes
  • Aspergillus is resistant
  • Resistance is common
  • Leishmania
  • Staphylococcus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ketaconazole:

Pharmacokinetics

A
  • GIT absorption dependent on acid environment
    • very poorly absorbed in horses, ineffective
    • Do NOT administer with acid suppression therapy
      • PPI’s
      • H2 antagonists
      • Antacids
      • Sucralfate
    • Variable GIT absorption in dogs and cats “GIVE W/ FOOD”
  • Hepatic Metabolism
  • Higher doses for CNS infections - fair penetration
17
Q

Ketoconazole:

Adverse Effects

A
  • Nausea, anorexia, vomiting
  • Hepatoxicity
  • Decrease Cortisol synthesis
  • Cataracts
  • Hair coat lightening
  • CYP3A inhibitor
    • decreased metabolism of CYP substrates
    • Includes: Cyclosporine, digoxin, Cisapride
  • P-gp inhibitor
18
Q

itraconazole

A

Similar to ketoconazole

  • inhibits CYP

Minimal effects on steroid synthesis

As dose increases, Adverse Effects increase

19
Q

Itraconazole:

Adverse Effects

A

Nausea, Anorexia, Vomiting

Heptaotoxicity

20
Q

Itraconazole:

Spectrum

A

Broad

Less resistance, higher efficacy in many organisms especially Aspergillus and other systemic diseases

Treatment of choice for many fungal organisms

Spectrum includes Leishmania

21
Q

Itraconazole:

Pharmacokinetics

A
  • Liquid formulation better absorption than capsules
  • Absorbed bes in acidic envrinments (PO)
    • poor oral bioavailability in horses
    • Rarely used in horses due to cost
  • Compounded formulations drastically decrease PO
    • DO NOT USE
    • Itraconazole is an unstable drug
    • Little to no absorption from compounded forms
  • Clinically effective for CNS infections
  • Hepatic Metabolism
22
Q

Itraconazole:

Uses

A
  • Typically daily dosing for systemic fungal diseases
    • Aspergillus, Blastomyces, Histoplasma, Cryptococcus, Coccidioides, Candida
  • 20kg dogs ~ $1.50 per day
  • Dermatophyes
    • Trichyophyton, Microsporum
    • Pulse Dosing:
      • BID for week or week on/week off
      • High lipophilicity, incorporation into stratum corneum
23
Q

Fluconazole:

Spectrum

A

Broad:

  • Good activity:
    • Blastomyces
    • Histoplasma
    • Cryptococcus
    • Coccidioides
    • Candida
  • Poor activity:
    • Aspergillus
    • Filamentous Fungi
    • Dermatophytes
    • Malassezia
  • Activity against Leishmania
24
Q

Fluconazole:

Pharmacokinetics

A
  • Well absorbed orally (even in horses)
    • Water soluble
    • Some effect on mammalian CYP
    • Best GIT tolerance
    • Hepatotoxicity similar to itraconazole
  • Penetrates well into CNS
    • treatment of choice for CNS infections with susceptible organisms
  • Renal Elimination
  • Active in urine
    • fungal cystitis
  • 20kg dog ~$1.50 per day
25
Q

Fluconazole:

Drug Interactions

A
  • Tramadol
    • increases tramadol oral bioavailability in dogs
  • Methadone
    • Increases oral bioavailability and duration of effect in dogs
    • ~12hrs duration post dose
    • Makes methadone effective in controlling postoperative pain in canine spays
  • Ketamine/Midazolam
    • Increases time to standing from ~30 to ~90 minutes in dogs
26
Q

Voriconazole:

Spectrum

A

Broad

  • Used primarily for resistant organisms and topically for equine fungal keratitis
  • High intrinsic activity against Aspergillus and Fusarium
    • Treatment of choice in people
27
Q

Voriconazole:

Pharmacokinetics

A
  • Well absorbed orally:
    • horses, dogs, cats
    • Fluconazole derivative
  • Hepatic Metabolism
  • Penetrates into CNS and aqueous humor
    • Less than fluconazole, but likely therapeutic
  • 20kg dog ~$5 per day
28
Q

Voriconazole:

Uses

A
  • Topically -
    • penetrates cornea and acheives high concentrations in aqueous humor
  • Topical treatment
    • drug of choice for equine fungal keratitis
29
Q

Voriconazole:

Adverse Effects

A

Hepatotoxicity

Transient visual disturbances

rash

Less effect on mammalian CYP

30
Q

Terbinafine:

MOA

A
  • Inhibition of squalene epoxidase
  • Decrease ergosterol synthesis
  • Disruption of cell membrane
31
Q

Terbinafine:

Spectrum

A

Broad

  • Dermatophytes:
    • Trichyophyton
    • Microsporum
  • Cryptococcus
  • Aspergillus
  • Blastomyces
  • Coccidioides
  • Histoplasma
  • Malassezia
  • Poor activity:
    • Candida
32
Q

Terbinafine:

Pharmacokinetics

A
  • Poor penetration into CNS
  • Primarily eliminated by hepatic metabolism
  • Recent PK data available
    • dogs and horses
    • Higher concentrations in dogs, little effects expected in horses
    • Half-life ~8hrs
33
Q

Terbinafine:

Adverse Effects

A

Vomiting, Anorexia, Hepatotoxicity

34
Q

Terbinafine:

Uses

A
  • Limited Data in Animals
    • Some studies show efficacy in dogs / cats for dermatophytes
    • Use in horses
      • low concentrations may not be effective for Aspergillus, Fusarium spp.
      • Unproven safety, but has been used
    • Generics are available, affordable
    • 20kg dog ~$0.50 per day
35
Q

Topical Use Only Antifungals

A

Effective for lovalized infections only

36
Q

Nystatin:

A
  • Similar to amphotericin in spectrum
  • Primarily used for Malassezia otitis in dogs
  • High Renal Toxicitiy if administered systemically
  • Discovered on dairy farm in Fauquier County Va.
37
Q

Miconazole, Clotrimazole

A
  • Similar spectrum to itraconazole
  • Malassezia otitis, localized dermatophyte infections
  • Some formulations of clotrimazole infused into sinus cavities for canine nasal Aspergillus infections

General Pharmacology 2 (17 decks)

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