Chapter 36- Antiparasitics Flashcards
What is the clinical application of chloroquine
Malaria, all species
What are some adverse reactions seen with chloroquine
Retinopathy, prolonged QT interval, methemoglobinemia, pruritis
What is a contraindication to chloroquine use
Visual field changes
What is the exact mechanism of action of chloroquine
Protonated chloroquine accumulates inside the parasite’s food vacuole, where it binds to ferriprotoporphyrin IX (heme) and inhibits its polymerization
What stage of plasmodia infections does chloroquine kill
Erythrocytic stage only
What is the clinical application of quinine (quinidine)
Malaria, especially P. Falciparum
What antimalarial agent that is an inhibitor of heme metabolism can cause cinchonism (tinnitus, deafness, headaches, nausea, vomiting, visual disturbances)
Quinine
What are some contraindications for quinine use
G6PD, myasthenia gravis
What specific type of malaria is quinine used for
Acute blood-stage malaria, but not used prophylactically
What is the clinical application of mefloquine
Chloroquine-resistant malaria
What anti-malarial agent that inhibits heme metabolism has neuropsychiatric symptoms
Mefloquine
What are is the proposed mechanism of mefloquine
Appears to disrupt polymerization of heme to hemozoin inside intraerythrocytic malarial parasites
What is the mechanism of action of primaquine
Disrupts metabolism in plasmodia mitochondria, likely by inhibiting ubiquinone and by non-specific oxidative damage
What is the clinical application of primaquine
P. Vivax and P. Ovale (attacks hepatic form)
What is a contraindication for primaquine
G6PD- it crosses placenta and DNA induce fatal hemolysis in fetal erythrocytes independent of maternal G6Pd status
What antimalarial drug can also target toxoplasmosis and babesiosis
Atovaquone
What is the mechanism of action of atovaquone
Inhibits the interaction between reduced ubiquinone and the cytochrome Bc1 complex (disrupts pyrimidine synthesis)
What analogues are sulfadoxine and sulfalene
PABA analogues that competitive inhibit plasmodial dihydropteroate synthetase
What analogue is pyrimethamine
Folate analogue that competitively inhibits plasmodial dihydrofolate reductase
What stage of P. Falciparum infection is sulfadoxine/sulfalene-pyrimethamine effective against
Schizont stage