Burkin: Parasitic Pharmacology Flashcards
What are these drugs used for?
Quinine
Chloroquine
Primarquine
Antimetabolites
Malaria
What are other drugs used to treat protozoan parasites?
metronidazole
diloxanide
nifurtimox
suramin
Which antimalarial drug is active against malaria when it is NOT in RBCs? What about when it is in RBCs?
primaquine; chloroquine and quinine
Different antimalarial drugs act at different stages of the malarial parasite’s life cycle. Which drug works when the parasite is NOT within RBCs?
paraquine
What is the method of action of quinine? What is it used to treat?
blocks heme polymerization so that heme concentrations are at toxic levels to parasites; used to treat chloroquine resistant Plasmodium falciparum
What is an adverse reaction caused by quinine?
cinchonism (similar to salicylate toxicity), curare effect, myocardial depression
How does chloroquine work? What is it used to treat?
blocks polymerization of heme, leading to toxic heme concentrations (toxic to parasites); works against ERYTHROCYTIC forms - used for acute malarial attacks, prophylaxis (prevention)
What are the effects of chloroquine if used for prophylaxis? If used acutely? If used in large doses?
little toxicity; anorexia, vomiting, nausea, headache; photosensitivity, retinopathy, leukopenia
How does primaquine work?
binds to DNA –> damages mitochondria via oxidative stress –> inhibits protein synthesis
What is primaquine used for?
liver forms of P. vivax and P. ovale
**not very effective against P. falciparum or P. malariae
Adverse reactions for primaquine?
same as chloroquine + hemolytic anemia
What types of patients are particularly prone to hemolytic anemia while taking primaquine?
those with G6PDH deficiency
How does pyrimethamine-sulfadoxine work?
inhibits dihydrofolate reductase (in PABA/DHF/THF pathway) - no folic acid synthesis - can’t form DNA
What is the pathway that takes PABA to DNA and RNA?
PABA –> DHF acid via sulfadoxine
DHF –> THF via pyrimethamine
THF –> DNA and RNA
What is pyrimethamine-sulfadozine used to treat?
cholorquine-resistant P. falciparum
What is the mechanism of action of metronidazole?
prodrug that is activated by electron transport proteins in ANAEROBES and PROTOZOANS –> produces cytotoxic metabolites that damage DNA
What is metronidazole used for?
amebiasis
trichomoniasis
giardiasis
anaerobic bacterial infections
What is one adverse effect to keep in mind when talking about metronidazole?
potentially mutagenic to fetus
What is the mechanism of action of Nifurtimox? What is it used for?
oxidative damage to DNA; Chagas disease
What is the mechanism of action of suramin? What is it used for?
inhibits multiple enzymes, esp enzymes important for energy metabolism; African trypanosomiasis (pre-CNS)
What is the most common helminthic parasite infection?
ancylostoma and necator (hookworms)
What is praziquantel used for? Method of action?
broad spectrum for cestodes (tapeworm) and flukes; massive Ca++ influx causes muscle contraction of parasite
Side effects of praziquantel?
nausea
vomiting
abdominal pain
What is bithionol used for? Adverse effects?
alternative to praziquantel - uncouples oxidative phosphorylation - used for lung and liver fluke infections; causes nausea, vomiting, diarrhea, rashes, photosensitivity
This drug us useful in treating chloroquine and Fansidar-resistant strains of malaria
mefloquine
What are two antimetabolites used to treat malaria
chloroguanide
pyrimethamine-sulfadozine (fansidar)
Three drugs used to treat Entamoeba histolytica
Paramomycin
Iodoquinol
Diloxanide furoate
List four very important nematodes
Tricuris trichuria - whipworm
Ascaris lumbricoides - roundworm
Ancylostoma duodenale - hookworm
Strongyloides stercoralis - threadworm
How does mebendazole work? What is it used for?
binds to tubulin and disrupts microtubules; used broad spectrum - for trichuriasis, hookworms, enterobiasis, ascariasis
Should mebendazole/albendazole be taken during pregnancy?
no - potential teratogen
How does albendazole work? What is it used to treat?
disrupts microtubules; used for Strongyloidiasis; trichurasis; capillariasis, ascariasis, filariasis, toxocariasis; Taenium Solium and Cysticercus cellulosis; Echinococcosis (hydatid disease)
How does thiabendazole work? What is it used to treat?
binds to tubulin, also blocks helminth specific enzyme fumarate reductase; used to treat Strongyloidiasis
What are the filarial worms, or roundworms?
Trichinella spiralis
Wucheria bancrofti
Onchocerca volvulus
Brugia malayi
What drug is used for tissue and blood nematodes (filariasis)?
diethylcarbamazine
How does Ivermectin work? What is it used to treat?
tonic paralysis of musculature via Cl- channels opening; used for nematodes (Onchocerciasis, enterobius, strongyloides, trichuris, ascaris)
