Antifungals Flashcards Preview

Step 1 Flash Cards > Antifungals > Flashcards

Flashcards in Antifungals Deck (14):
1

amphotericin B mechanism

- binds ergosterol (unique to fungi)- forms membrane pores that allow leakage of electrolytes

2

amphotericin B clinical use

- serious, systemic mycoses
- cryptococcus, coccidiodes, histoplasma, candida, mucor
- intrathecally for fungal meningitis
- supplement K and Mg because of altered renal tubule permeability

3

amphotericin B toxicity

- fevers/chills "shake and bake", hypotension, nephrotoxic (dose-dependent), arrhythmias (hypoMg, hypoK), anemia, IV phlebitis
- hydration decreases nephrotoxicity, liposomal amphotericin decreases tox

4

nystatin mechanism and use

- same mech as amphotericin B, topical form because too toxic for systemic use
- "swish and swallow" for oral canidiasis, topical form for diaper rash or vaginal candidiasis

5

azoles mechanism

mech - inhibit fungal sterol (ergosterol) synthesis by inhibiting cytochrome P450 enzyme that converts lanosterol to ergosterol

6

azoles clinical use

local and less serious systemic mycoses
- fluconazole for suppression for cryptococcal meningitis in AIDS pts and candidal infections of all types
- itraconazole for blastomycoses, coccidioides, histoplasma
- clotrimazole and miconazole for topical fungal infections

7

azoles toxicity

testosterone synthesis inhibition (gynecomastia), liver dysfunction

8

flucytosine

- mech: inhibits DNA and RNA biosynthesis by conversion to 5FU by cytosine deaminase
- use: systemic fungal infections (esp cryptococcal meningitis) in combo with amphotericin B
- tox: BM suppression

9

echinocandins

- caspofungin, micafungin, anidulafungin
- mech: inhibits cell wall synthesis by inhibiting synthesis of b-glucan
- used for invasive aspergillosis, candida
- tox: GI upset, flushing

10

terbinafine

- mech: inhibits the fungal enzyme squalene epoxidase - inhibits ergosterol synthesis
- use: dermatophytoses (esp onychomycoses)
- tox: GI upset, headaches, hepatotoxicity, taste disturbance

11

griseofulvin

- interferes with microtubule function, disrupts mitosis, deposits in keratin-containing tissues (nails)
- used for oral treatment of superficial infections, inibits growth of dermatophytoses
- tox: teratogenic, carcinogenic, confusion, headaches, inc P450 metabolism

12

antiprotozoan therapy

- pyrimethamine (toxo), suramin and melarsoprol (typanosoma brucei), nifurtimox (t. cruzi), sodium stibogluconate (leishmaniasis)

13

chloroquine

- blocks detoxification of heme into hemozoin
- heme accumulates and is toxic to plasmodia
- used for treatment of plasmodial species other than falciparum (they have resistance due to membrane pump)
- for life-threatening malaria, treat with quinidine or artesunate
- tox: retinopathy, pruritis

14

antihelminthic therapy

- mebendazole, pyrantel pamoate, ivermectin, diethylcarbamazine, praziquantel
- immobilize helminths
- use praziquantel against flukes (trematodes) like schistosoma