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anti-parasitic drugs
GI
43
Medical
Graduate
09/09/2010

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Term
what is the most deadly spp of plasmodium? where is it found?
Definition
plasmodium falciparum - found in africa
Term
which pts are resistant to infection by plasmodium vivax?
Definition
pts who lack the duffy coat receptor for binding
Term
which forms of plasmodium can cause relapsing malaria? why?
Definition
vivax and ovale - b/c they form hypnozoites
Term
what kind of parasite is plasmodium?
Definition
intra-erythrocytic
Term
what is the usual route of transmission for malaria?
Definition
female anophelene mosquitoes
Term
what is the simplified plasmodium lifecycle?
Definition
an infected female anophelene mosquito is itself infected, it then bites a human and injects sporozoites which go to the liver and mature through an asexual cycle and are released as merozoites which infect the RBCs
Term
why is malaria vaccine hard to produce?
Definition
b/c the life cycle is complex and there are many antigenic changes
Term
what is the MOA for the anti-malarial chloroquine?
Definition
plasmodium has to convert heme (which is toxic to it) into hemazoin during its intra-erythrocytic phase, and chloroquine blocks this conversion.
Term
what kind of immunity do pts living in countries where malaria is endemic have?
Definition
partial and non-sterilizing, due to repeated challenges. they are for the most part immune, but if they leave their country, they become naive
Term
what is a common side effect of chloroquine?
Definition
hypotension, pruritis in africans, and hair hypopigmentation
Term
how was quinine administered before its rx-potential was known? where does it come from?
Definition
as a tea, quinine comes from the cinchona tree
Term
what is the MOA for quinidine?
Definition
same as chloroquine: plasmodium has to convert heme (which is toxic to it) into hemazoin during its intra-erythrocytic phase, and quinine blocks this conversion.
Term
what is cinchonism?
Definition
tinnitus, headache, dizziness, impaired high tone hearing, vertigo, uticaria, skin flushing, fever, dysphoria, and visual disturbances
Term
what are the ADRs for quinine?
Definition
cinchonism, hypoglycemia (due to parasites consumption of glucose/release of insulin from pancreas by quinine), blackwater fever (massive hemolysis due to malaria/anti-malarials, presents as hematuria and esp in G6PD pts), and hemoglobinuria
Term
when is malaria a medical emergency?
Definition
when more than 5% of RBCs are parasitized
Term
why are anti-malarials so greatly researched?
Definition
so western countries can fight in tropical areas
Term
can mefloquine/lariam be given prophylactically or as tx?
Definition
either
Term
what are the ADRs for mefloquine/lariam?
Definition
neuropsychiatric
Term
what happens if a pt vomits after taking mefloquine/lariam?
Definition
they should repeat the dose if it was w/in the first hr
Term
what is malarone?
Definition
a fixed dose combination of atovaquone (also used in pneumocycstis jirovecii, t. gondii, babesia microti) and proguanil
Term
what are ADRs for malarone?
Definition
skin rash, insomnia, hyponatremia - will interact with other rxs. also not recommended in children or pregnant/breastfeeding women due to renal impairment
Term
what is useful about malarone?
Definition
you can start it the day before you need it
Term
what other disease besides malaria is dapsone used in?
Definition
leprosy
Term
what is dapsone syndrome?
Definition
rash, fever, jaundice, and eosinophilia
Term
can tetracycline/doxy be used against malaria? what might ADRs be?
Definition
yes, for tx/prophylaxis. ADRs: photosensitivity, tooth discoloration, and cannot be used in children <9 or pregnant women
Term
what drug is used for plasmodium vivax and ovale, the spp responsible for hyponozoite formation/relapsing malaria?
Definition
primaquine
Term
what is an ADR for primaquine?
Definition
it can cause hemolytic anemia in pts with G6PD deficiency (which is how the disorder was discovered)
Term
what drugs work at the hepatic stage of the schizonticide?
Definition
malarone, primaquine
Term
what drugs work at the blood stage of the schizonticide?
Definition
malarone, doxy, mefloquine, choroquine
Term
is plasmodium falciparum drug resistant?
Definition
yes, it is amount the top 10
Term
what is beneficial about the combination pill of artesunate and mefloquine?
Definition
it is color coded and pts only have to take it x2/day -> better compliance
Term
what are the artemisinins?
Definition
lactones extracted from sweet wormwood which is a potent and rapidly acting blood schizonticide. derivatives are artemether, artemotil, and artesunate. it was even prescribed by chinese physicians.
Term
what is one reason for resistance to anti-malarials?
Definition
HIV initially presents as a fever, so it is over prescribed
Term
what is useful about combining arteminsins with other anti-malarials?
Definition
they can attack different portions of the parasite's life cycle
Term
which drugs can be prescribed to pregnant pts?
Definition
chloroquine, quinine (abortive in high dosages), and clindamycin
Term
which are the big 3 anti-malarials?
Definition
mefloquine, doxy, and malarone
Term
what is complicated malaria?
Definition
this is a medical emergency and involves: unarousable coma, hypoglycemia, oliguria, renal failure, DIC, ARDS, circulatory shock, severe anemia, PE, and jaundice
Term
what is tx for complicated malaria?
Definition
quinidine gluconate or artesunate
Term
what is metronizadole (or tinidazole) good for? ADRs?
Definition
anaerobic, protozoan, and H. pylori. ADRs: disulfiram-like effect (abd distress, vomiting, flushing, headache if pts drink alcohol w/in 3 days)
Term
what is pentamidine good for?
Definition
pneumocystis jirovecii via inhaled aerosol
Term
what is nitazoxanide good for?
Definition
cryptosporidiosis and giardiasis
Term
what is furazolidone good for?
Definition
giardiasis
Term
what is paromomycin good for?
Definition
amebiasis (it is a luminal agent like idoquinol)
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