Antifungal Therapy Flashcards Preview

First Aid: Microbiology > Antifungal Therapy > Flashcards

Flashcards in Antifungal Therapy Deck (24):
1

Amphotericin B

mechanism 

Amphotericin "tears" holes 

  • binds ergosterol 
  • forms membrane pores 
  • allows leakage of electrolytes 

2

Amphotericin B 

clinical use 

  • serious, systemic mycoses 
  • Cryptococcus
  • Blastomyces
  • Coccidioides
  • Histoplasma
  • Candida 
  • Mucor 
  • intrathecally for fungal meningitis 
  • supplement K+ & M2+ (altered renal tubule permeability)

3

Amphotericin B 

toxicity 

  • fever/chills ("shake & bake")
  • hypotension
  • nephrotoxicity 
  • arrhythmias
  • anemia
  • IV phlebitis 
  • hydration decreases nephrotoxicity 
  • liposomal amphotericin decreases toxicity 

4

Nystatin

mechanism 

  • same as amphotericin B
  • topical form
  • too toxic for systemic use 

5

Nystatin

clinical use 

  • "swish & swallow" for oral candidiasis (thrush)
  • topical for diaper rash or vaginal candidiasis 

6

Azoles

  • fluconazole
  • ketoconazole
  • clotrimazole
  • miconazole
  • itraconazole
  • voriconazole

7

Azoles

mechanism 

  • inhibit fungal sterol (ergosterol) synthesis 
  • inhibit CYP450 enzyme that converts lanosterol to ergosterol 

8

Azoles

clinical use 

  • local & less serious systemic mycoses 
  • fluconazole - chronic suppression of cryptococcal meningitis in AIDS patients & candidal infections of all types
  • itraconazole - Blastomyces, Coccidioides, Histoplasma 
  • clotrimazole & miconazole - topical fungal infections 

9

Azoles

toxicity 

  • testosterone synthesis inhibition 
    • gynecomastia (ketoconazole)
  • liver dysfunction 
    • inhibits CYP450

10

Flucytosine 

mechanism 

  • inhibits DNA & RNA biosynthesis 
  • conversion to 5-FU by cytosine deaminase 

11

Flucytosine

clinical use 

toxicity 

  • systemic fungal infections 
  • combination w/ amphotericin B
  • bone marrow suppression

12

Echinocandins 

  • caspofungin 
  • micafungin
  • anidulafungin

13

Echinocandins 

mechanism 

inhibits cell wall synthesis 

inhibits synthesis of ß-glucan

14

Echinocandins

clinical use

toxicity 

  • invasive aspergillosis, Candida
  • GI upset, flushing (histamine release)

15

Terbinafine

mechanism 

inhibits the fungal enzyme squalene epoxidase 

16

Terbinafine

clinical use

toxicity 

  • dermatophytoses 
  • GI upset, headaches, hepatotoxicity, taste disturbance 

17

Griseofulvin

mechanism 

  • interferes w/ MT function
  • disrupts mitosis 
  • deposits in keratin-containing tissues (nails)

18

Griseofulvin

clinical use 

  • oral treatment of superficial infections
  • inhibits growth of dermatophytes 
    • tinea, ringworm 

19

Griseofulvin

toxicity 

  • teratogenic
  • carcinogenic
  • confusion
  • headaches
  • increased P450 & warfarin metabolism

20

Antiprotozoan therapy 

  • Toxoplasmosis 
  • Trypanosoma brucei 
  • T. cruzi
  • Leishmaniasis 

  • Toxoplasmosis 
    • pyrimethamine
  • Trypanosoma brucei 
    • suramin
    • melarsoprol
  • T. cruzi
    • nifurtimox 
  • Leishmaniasis 
    • sodium stibogluconate 

21

Chloroquine 

mechanism 

  • blocks detoxification of heme into hemozoin 
  • heme accumulates & is toxic to plasmodia 

22

Chloroquine

clinical use 

  • treatment of plasmodial species other than P. falciparum 
  • resistance due to membrane pump (decreases intracellular conc of drug)
  • treat P. falciparum w/ artemether/lumefantrine or atovaquone/proguanil
  • life threatening malaria: quinidine 

23

Chloroquine 

toxicity 

  • retinopathy
  • pruritis (esp dark skinned individuals)

24

antihelminthic therapy 

 

  • mebendazole, pyrantel pamoate, ivermectin, diethylcarbamazine, praziquantel (immobilize helminths)
  • flukes (schistosoma): praziquantal