Antiparasitic Agents Flashcards
Drugs used to tx malaria
Artemether/lumefantrine
Chloroquine
Primaquine
Malarial prophylaxis
Chloroquine
Primaquine
Antimalarial schinzonticides blood stage: clinical cure
Chloroquine
Artemisinins
Antimalarial schinzonticides liver stage, radial cure:
Primaquine
Cure of relapsing malaria
Blood stage Antimalarials are ______ against liver stage parasites
Ineffective
2 agents who also have gametocidal activity, no clinical benefit but disrupts transmission
Artemether
Primaquine
Chloroquine
Antimalarial
Weak base that becomes trapped in acidic parasite food vacuoles, accumulates in infected RBC
-digestion of hemoglobin liberates heme which is toxic to the parasite
Chloroquine resistance due to
Mutated vacuolar efflux transporter (PfCRT)
Chloroquine beneficial for …
Treating pregnant women
Chloroquine adverse rxns
Generally well tolerated with prophylaxis
In doses for clinical cure-pruritis, HA, GI effects, cardiovascular toxicity
Artemether
Antimalarial
Derived from Chinese plant qinghao
Not useful for prophylaxis
Artemether therapeutic use and adverse rxns
Used in combo with lumefantrine to slow resistance
First line oral tx of MDR falciparum malaria
Neurotoxicity
Potential embryotoxicity
Primaquine
Antimalarial - used in the liver stage
Used with chloroquine to achieve clinical and radical cure
Terminal prophylaxis after travel to endemic areas (vivas/ovale)
Primaquine adverse rxns
Induces hemolytic anemia in G6PD deficiency
Can’t use in pregnant women,
Makes it hard to use in endemic areas
Metronidazole (antiprotazoal)
Treats systemic protozoans Used for: 1) amebiasis - given w/ luminal amebicide (metronidiazole levels low in GI tract 2) giardiasis 3) trichomoniasis
Paromomycin
Luminal antiprotazoal agent
Aminoglycoside that binds to 30s ribosomal subunit
Not absorbed from GI tract so not for systemic infections
Paromomycin therapeutic uses
Alone - asymptomatic amebiasis
In combo w/metronidazole for amebic colitis/dysentery
1st trimester pregnant females being tx for giardiasis
Albendazole
Antihelminthic (parasitic worms)
Inhibits polymerization of parasitic tubulin, preventing formation of cytoplasmic micro tubules, disrupts nematode motility and DNA replication
Albendazole uses and effects
Cestode infections
Roundworm
Pinworms
Teratogenic
Liver toxicity with long term use
Praziquantel
Increases permeability of Trematode and Cestode cell membranes to Ca = paralysis, dislodgement and death
Drug of choice for schistosomiasis
Pyrantel pamoate
Depolarizing neuromuscular blocking agent
Persistant activation of parasite nicotinic ACh receptors and inhibition of AChE - spastic paralysis of worms
Available OTC
Ivermectin
Immobilization of worms by tonic muscle paralysis
Cl- channels (glutamate-gated) only found in invertebrates
= hyperpolarization of cell membrane
Ivermectin use
Used in veterinary medicine to tx infections by nematodes and arthropods (insects, ticks, fleas, mites)
River blindness (onchocerciasis) in humans -mazzotti rxn from dying worms
