Antifungals/Antiprotazoal Flashcards
Mechanism of amphotericin B
binds ergosterol (unique to fungi) forms membrane pores that allow leakage of electrolytes
Use of amphotericin B
serious, systemic mycoses
Crypto - w/wo flutocytosine for meningitis
Blasto, Histo, Candida, Mucor
Intrathecally for fungal meningitis
what electrolytes should you supplement with amphotericin B use?
K+ and Mg2+ because of altered renal tubule permeability
Toxicity of amphotericin B
fever/chills hypotension nephrotoxicity arrhythmias anemia IV phlebitis hydration decreases nephrototixicty liposomal amphotericin decreases toxicity
Mechanism of nystatin
same as amphotericin B
topical use only as too toxic for systemic use
Use of nystatin
“swish and swallow” for oral candidiasis (thrush); topical for diaper rash or vaginal candidiasis
Mechanism of flucytosine
inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase
Use of flucytosine
systemic fungal infections (especially meningitis caused by cryptococcus) in combination with amphotericin B
Toxicity of flucytosine
bone marrow suppression
Name the azoles
clotrimazole, fluconazole, itraconazole, ketoconazole, miconazole, voriconazole
Mechanism of the azoles
inhibit fungal sterol (ergosterol) synthesis by inhibiting cytochrome p450 enzyme that converts lanosterol to ergosterol
Use of azoles
local and less serious systemic mycoses
Use of fluconzaole
chronic suppression of cryptococcal meningitis in AIDS patients and candidal infections of all types
Use of itraconazole
blastomycoses, coccidioides, histo
Use of clotrimazole and miconazole
topical fungal infections
Mechanism of terbinafine
inhibits the fungal enzyme squalene epoxidase
Use of terbinafine
dermatophytoses (especially onychomycosis - fungal infection of finger or toe nails)
Toxicity of terbinafine
GI upset, headache, hepatotoxicity, taste disturbance
Name the echinocandins
anidulafungin, caspofungin, micafungin
Mechanism of echinocandins
inhibit cell wall synthesis by inhibiting synthesis of beta-glucan
Use of echinocandins
invasive aspergillosis, Candida
Toxicity of echinocandins
GI upset, flushing (by histamine release)
Mechanism of griseofulvin
interferes with microtubule function, disrupts mitosis
deposits in keratin-containing tissues (e.g. nails)
Use of griseofulvin
oral treatment of superficial infections; inhibits growth of dermatophytes (tinea, ringworm)
Toxicity of griseofulvin
teratogenic, carcinogenic, confusion, headaches, increased cytochrome p-450 and warfarin metabolism
Use of pyrimethamine
toxoplasmosis
Use of suramin and melarsoprol
trypanosoma brucei
Use of nifurtimox
T. cruzi
Use of sodium stibogluconate
Leishmaniasis
Drugs to treat scabies and lice
permethrin
malathion
lindane
Mechanism of permethrin
blocks Na+ channels –> neurotoxicity
Mechanism of malathion
acetylcholinesterase inhibitor
Mechanism of lindane
blocks GABA channels –> neurotoxicity
Mechanism of chloroquine
blocks detoxification of heme into hemozoin
heme accumulates and is toxic to plasmodia
Use of chloroquine
tx of plasmodial species other than P. falciparum (frequency of resistance in P. falciparum is too high)
Mechanism of resistance to chloroquine
membrane pump that decreases intracellular concentration of drug
Tx of resistant malaria?
arthemether/lumefantrine or atovaquone/proguanil
Tx for life-threatening malaria?
quinidine (in US) or quinine (elsewhere) or artesunate
Name antihelminthic drugs
mebendazole, pyrantel pamoate, ivermectin
diethylcarbamazine, praziquantel
