Antiparistics Flashcards
Antimalarials
Chloroquine, primaquine, artemether
Prophylactic antimalarials
Chloroquine and primaquine
Treatment antimalarials
Artemether/lumefantrine
Chloroquine
Primaquine
Blood stage antimalarials
Chloroquine
Artemether
Liver stage antimalarials
Primaquine
3 characteristics of prophylactic agents
Low toxicity
Orally effective
Long half-life
Prophylaxis prevents what stage of malaria?
Blood stage
Chloroquine MOA
Weak base trapped in acidic parasite
Inhibits biocrystallization to increase heme concentration in food vacuole
Heme toxic to parasite
Chloroquine uses
Clinical cure & Prophylaxis against sensitive strains
Is chloroquine safe for pregnancy?
Yes
Chloroquine side effects
CV toxicity
Chloroquine resistance due to…
Mutated vacuole efflux transporter (PfRCT)
Chloroquine does not work for…
P. Falciparum in Asia, Africa, S. America
Artemether MOA
Maybe converted to toxic free radicals by heme
Artemether Uses
Fixed dose w/ lumefantrine
Oral drug for MDR falciparum
Artesunate (IV)
Artemether side effects
Neurotoxicity & embryotoxicity
Artemether PK (when not w/ lumefantrine)
Absorbed from GI tract —> short half-life
Does NOT work as prophylactic
Artemether Fun Fact
Inactive counterfeit to mimic drug
Liver Antimalarial
Primaquine
Primaquine MOA
Unknown
Primaquine Uses
Clinical & radical cure of vivax/ovale (take w/ chloroquine)
Terminal prophylaxis for vivax/ovale regions
Primary prophylaxis if other drugs inappropriate
Primaquine side effects
Mild cyanosis in normal G6PD
Hemolytic anemia in G6PD deficiency
Primaquine contraindications
G6PD deficiency
Pregnancy
Antiprotozoal Drugs
Metronidazole
Paromomycin
Common protozoans in USA
Trichomoniasis
Giardiasis
Amebiasis
Cryptosporidiosis
Classifications of antiprotozoal agents
Systemic
Luminal - agents not absorbed
Metronidazole classification
Systemic
Metronidazole MOA
Prodrug
DNA damaging metabolite by anaerobic organism
Metronidazole Uses
Amebiasis, giardiasis, trichomoniasis, anaerobic bacteria
For amebiasis, add luminal amebicide to eradicate luminal “survivors”
Metronidazole side effects
Metallic taste
Red/brown urine
Carcinogenic
Nitazoxanide uses
Diarrhea caused by cryptosporidiosis or giardiasis
Nitazoxanide MOA
Pyruvate Ferrell in oxidoreductase inhibitor
Paromomycin classification
Luminal antiprotozoal
Paromomycin MOA
Binds 30s subunit of S hisolytica
Inhibits protein synthesis (not absorbed by GI, so can’t treat systemic infections)
Paromomycin uses
Asymptomatic amebiasis (solo)
Amebic colitis/dysentery (combo w metro)
1st trimester pregnant pts w/ giardiasis
Antihelminthics
Albendazole
Praziquantel
Ivermectin
Nematodes
Round worms
Cestodes
Tapeworms
Trematodes
Flukes
How do humans get worms?
Ingestion of eggs/larvae in food or soil to skin
Worms lodge in digestive tissue
Neurocysticercosis
Ingestion of undercooked pork or feces contaminated w/ Taenia solium tapeworm eggs
Cysts in brain cause seizures
Most common infection in kids in USA age 5-10 years old
Enterobiasis (pinworm)
Single dose antihelminthic
Expels worms from GI tract
Extended treatment antihelminthic
Systemically eradicate adults or developmental forms in other tissues
Antihelminthic prototype
Albendazole
Albendazole MOA
Block polymerization of B-tubulin, disrupts nematode motility and uptake of glucose
Cell death in ~3 days
Best way to improve albendazole absorption
Take with fatty meal
Active form of albendazole
Albendazole sulfoxide
Albendazole uses
Cestode infections
Roundworm infections
Pinworm (400mg dose, two weeks apart)
Albendazole side effects
Teratogenic
Liver toxicity
Bone marrow suppression
Albendazole contraindications
Pregnancy
Praziquantel MOA
Increases perm of trematode & cestode membrane to Ca, causes paralysis, dislodgement, and worm death
Praziquantel use
Schistosomiasis
Most trematodes and cestodes
Cysticerosis
Praziquantel side effects
Fever, rash, itching associated w/ protein release from dying worms
Ivermectin MOA
Tonic muscle paralysis, activates glutamate gated Cl channels, hyperpolarization of cell
Why does Ivermectin not effect human cells?
Human cells have p-glycoprotein efflux transporters
Ivermectin uses
Fleas, ticks, mites
Onchocerciasis (river blindness)
Strongyloidiasis
Scabies, head lice
Ivermectin side effects
Mazzotti reaction
Cleft palate
Ivermectin contraindications
Pregnancy