Antifungals Flashcards
amphotericin B mechanism
binds ergosterol –> forms pores –> electrolyte leakage
ampho B specrum
systemic mycoses (cryptococcus, blastomyces, coccidiodes, histoplasma, candida. supplement w/ K+ / Mg2+ due to altered renal tubule permeability
amp B toxicity
fever / chills, hypotension, IV phlebitis, arrythmias, nephrotoxicity.
hydration –> dec. nephrotoxicity
nystatin
too toxic for systemic use.
punches pores in ergosterol membrane.
used for oral thrush / diaper rash
azoles mechanism
inhibit fungal synthesis by inhibiting P450 conversion of lanosterol to ergosterol
azole spectrum
1) local / less serious mycoses. 2) chronic suppression of cryptococcal meningitis in AIDS / candidal infections of all types.
specific treatment for blastomyces, coccidiodes, histoplasma
itraconazole
azole toxicity
1) inhibits testosterone synthesis –> gynecomastia
2) inhibition P450 –> liver dysfunction
flucytosine mechanism
inhibit DNA / RNA biosynthesis by conversion to 5-FU by cytosine deaminase
fluctyosine spectrum
systemic fungal infections (cryptococcus menigitis) in combo w/ ampho B
flucytosine toxicity
bone marrow suppression
echinocandins (ends in fungin)
inhibits b-glucan –> cell wall synthesis inhibition
echinocandins clinical use
invasive aspergillosis / candida
echinocandins toxicity
flushing via histamine release / GI upset
terbinafine
1) squalene epoxidase inhibition
2) dermatophytes (onychomycosis)
3) hepatotoxicity, taste disturbance
griseofulvin
1) interferes w/ microtubules –> mitosis disruption
2) superficial infxn / dermatophytes (tinea, ringworm)
3) teratogenic, carcinogenic, incr. P450 / warfarin metabolism
chloroquine mechanism
blocks detoxification of heme into hemozoin –> heme accumulation leads to toxicity in plasmodia
chloroquine spectrum
1) ineffective in p. falciparum (too much resistance)
life-threatening malaria treatment
quinidine / artesunate
p. falciparum treatment
artemether / lumefantrine OR atoaquone/proguanil
