Antifungal Agents Flashcards
Name the drug:
Binds ergosterol –> forms pores –> alter membrane permeability –> Leak Na+, K+, H+ –> cell death
Polyene antibotics: amphotericin B, nystatin
Name the drug:
Polymerized microtubules –>disrupt fungal mitosis
Griseofulvin
Name the drug:
Pyrimidine analog –> inhibits fungal DNA and RNA synthesis
Antimetabolites: flucytosine
Name the drug:
Blocks ergosterol synthesis by binding to and inhibiting fungal
cytochrome P450 enzyme lanosterol 14-alpha-demmthylase
Azoles: imidazoles, triazoles
Name the drug:
Block ergosterol synthesis at a step other than inhibited by azoles
Allylamines: terbinafine
Name the drug:
Inhibit synthesis of glucan
Caspofungin
Drug of choice for most life threatening systemic fungal infections (Candida, Aspergillus, Cryptococcus)
Amphotericin B
Amphotericin B
Fungicidal or fungistatic?
Fungicidal
Fungistatic depending on low pH, concentration, fungal organism
T/F: Amphotericin B is poorly absorbed in GI tract
True
Oral admin only for infections within GI lumen (topical)
Which of the follow is true about Amphotericin B?
A. It is highly soluble
B. It is excreted by the liver over a short amount of time
C. Resistance rarely develops
D. It is well absorbed from skin and mucous membranes
C
A. It is insoluable. Must be dissolved in bile salt detergent solution.
B. Excreted by kidney over prolonged amount of time
D. Poorly absorbed. Topical for superficial Candida infections
Lipid formulation of Amphotericin B is used to target ___
High concentrations found in:
Low concentration found in:
reticuloendothelial system
High concentration in liver, spleen, lung
Low concentration in kidney
Useful for pts w/ renal dysfunction requiring long term amph B
What adverse effect is nearly always associated w/ Amphotericin B?
Nephrotoxicity
Which of the following is NOT a drug interaction of Amphotericin B? A. Digitalis B. Griseofulvin C. Azoles D. Aminoglycosides E. Cyclosporine
B.
All others are drug interactions of Amphotericin B
Which of the following is TRUE?
A. Nystatin has a wider spectrum than amph B
B. Nystatin is administered parenterally, orally and topically
C. Amphotericin B has a bitter, unpleasant taste
D. Nystatin is drug of choice for candida infection of oral cavity.
E. It is well absorbed from skin, mucous membranes and GI tract
D
A. Narrower
B. Orally and topically. Too TOXIC to be used parenterally
C. Nystatin has a bitter, unpleasant taste
E. It is NOT well absorbed from skin, mucous membranes and GI tract
Griseofulvin
Fungicidal or fungistatic?
Fungistatic
Griseofulvin administration
Oral
Uses of Griseofulvin
Dermatophytosis (hair, nails, skin)
Name the drug:
Contraindicated for men who want children
Griseofulvin
Flucytosine
Fungicidal or fungistatic?
Fungistatic
Flucytosine administration
Oral
Flucytosine treats ___
systemic fungal infections, Severe Candida infections and Cryptococcus meningitis
T/F Flucytosine rarely develops resistance.
False. Resistance is common
Should be used in combination w/ amph B
Flucytosine is used in combination w/ ___
Amph B
Which of the following is FALSE about Flucytosine? A. Good oral bioavailability B. Poor CNS penetration C. Renal excretion D. GI intolerance is an adverse effect
B. GOOD CNS penetration: meningitis
T/F: Azoles bind to ergosterol to inhibit ergosterol synthesis.
False. Azoles do NOT bind to ergosterol.
It inhibits ergosterol synthesis by blocking fungal CYP enzyme activity
T/F: Azoles have a lot of drug interactions
True
Name 3 Imidazoles
Ketoconazole
Micronazole
Clotrimazole
Which azole?
Greater propensity to inhibit mammalian CYPs
Ketoconazole
Interfere w/ metabolism of other drugs –> enhance toxicity
Limited use
Which azole?
Effective topically against cutaneous candidiasis
Miconazole
Uses: Jock itch, ringworm, athlete’s foot, vaginal infections, oral thrush
Limited use due to toxicity
Which of the following is FALSE about Clotrimazole?
A. Liver metabolized
B. Highly effective alternative to fluconazole
C. May cause minor GI upset
D. Oral/topical administration
B. good alternative for nystatin
Drug of choice for oropharyngeal candidiasis in AIDS patients
Clotrimazole
Which of the following is NOT a triazole? A. Fluconazole B. Itraconazole C. Voriconazole D. Ketoconazole E. Efinaconazole
D. Ketoconazole is an imidazole
Posaconazole is also a triazole
Which of the follow is TRUE about Itraconazol?
A. It has a narrower spectrum than fluconazole
B. It has poor GI tract absorption
C. Oral and topical administration
D. Treatment of Aspergillus, fluconazole-resistant Candida infections
D
A. Broader
B. Good GI absorption
C. Oral, IV
Name the drug:
Better CNS penetration than other azoles
Fluconazole
Fluconazole resistance in: (3)
C. krusei
C. glabrata
NOT active against molds
Fluconazole administration
Oral, IV
First line agent for invasive infections by Candida and refractory mucocutaneous candidiasis
Fluconazole
Voriconazole is more potent in vitro against ___ (2)
Yeast
Mold
Voriconazole administration
Oral, IV
T/F: Voriconazole has low toxicity
True
Only azole w/ significant activity against zygomycoses
Posaconazole
T/F: Voriconazole has very little drug interactions
False. Inhibits CYP3A4
First line therapy for aspergillosis
Voriconazole
Name the drug:
A side effect that causes dose related, transient vision side effects
Voriconazole
T/F: Posaconazole is poor oral bioavailability
False
Better when diet contains high fat
Posaconazole uses
Prophylaxis of invasive fungal infection in BMT w/ GVHD and hematologic maligancy and prolonged neutropenia
Topical treatment of onychomycosis
Efinaconazole
Allylamines
Fungicidal or fungistatic?
Fungicidal
Which of the following is FALSE about allylamines? A. Good GI absorption B. Metabolized by liver C. Oral, IV administration D. Limited drug interaction
C. Topical, oral
D. True but co-admin w/ rifampicin and cimetidine affects clearance of terbinafine
Caspofungin, micafungin, anidulafungin are ___
glucan synthesis inhibitors
Used for invasive candidiasis resistant to other antifungals
Caspofungin: glucan synthesis inhibitors
Only azole w/ significant activity against zygomycoses
Posaconazole
Use for invasive aspergillosis/mold infections
Caspofungin: glucan synthesis inhibitors
Azole of choice for crytococcal meningitis
Fluconazole
Terbinafine is a ___
Allylamine
Mechanism of action of terbinafine
Inhibit cell membrane synthesis
