TBL 6 - Parasites and Antiparasitics Flashcards
What drug is used to treat asymptomatic Entamoeba histolytica?
Paromycin
What drug(s) are used to treat symptomatic Entamoeba histolytica?
Nitroimidazoles and Paromycin
What drug class does Paromycin belong to and what is its MoA?
It is an aminoglycoside, which is a 30s ribosomal inhibitor that blocks initiation complex formation.
What are some examples of aminoglycosides?
Gentamicin, Tobramicin, Amikacin, Streptomycin, and Paromycin.
What is the role of Paromycin when used for Entamoeba histolytica infections?
Eliminates intraluminal cysts/invading trophozoites.
What is an adverse effect of paromycin?
GI discomfort.
What are some examples of nitroimidazoles?
Metronidazole, Tinidazole, Benznidazole, and Fexinidazole.
What is the MoA of nitroimidazoles?
Generate reactive intermediates and free radicals.
What are some adverse effects of nitroimidazoles?
Metallic taste and disulfiram-like reaction (severe flushing, tachycardia, and hypotension).
What is the treatment of choice to treat Giardia duodenalis?
Nitroimidazoles (Metronidazole) or Nitazoxanide
What is the MoA of Nitazoxanide?
Same as nitroimidazoles; Generate reactive intermediates/free radicals.
What is the treatment for Leishmania?
Amphotericin B, Miltefosine, and Pentavalent Antimonial (Stibogluconate)
What is the MoA of Amphotericin?
Disrupts cell membranes by sequestering ergosterol which disrupts membrane integrity, leading to cell (fungal) death.
What are some adverse effects of Amphotericin?
Infusion reactions, nephrotoxicity, hypokalemia, hypomagnesemia, and arrhythmias.
What is the MoA of Miltefosine?
Interferes with cell membrane phospholipids, inhibits cytochrome c oxidase (mitochondrial function), and induces apoptosis-like cell death.
What is the MoA of Pentavalent Antimonial (Stibogluconate)?
Inhibits parasitic glycolysis.
What combination of drugs are used to treat Toxoplasma gondii?
Pyrimethamine, Sulfadiazine, and Leucovorin
What is the MoA of SMX (Sulfamethoxazole) and Sulfadiazine?
Dihydropteroate synthase inhibitor.
What is the MoA of Trimethoprim (TMX) and Pyrimethamine?
Dihydrofolate reductase inhibitor.
What is the MoA of Leucovorin?
Is a reduced form of folic acid that is used to restore active folate stores.
What are the adverse effects of Pyrimethamine, Sulfadiazine, and Leucovorin?
Sulfa allergies
Hypersensitivity reactions
Hemolytic anemia; avoid in G6PD deficiency
Photosensitivity
Kernicterus in infants
Avoid in pregnancy
Hyperkalemia
Bone marrow suppression
What is the prophylactic treatment for Toxoplasma gondii?
TMP-SMX
What medicine is used to treat taeniasis (from larvae and cysts)?
Praziquantel
What is the MoA of praziquantal?
Increases cell permeability to Ca2+ causing strong contractions and paralysis, leading to detachment.
What drugs are used to treat neurocysticercosis (from eggs)?
1-2 cysts: albendazole
More than 2 cysts: albendazole and praziquantel
What is the MoA of albendazole (Triclabendazole)?
Inhibit microtubule synthesis and function causing decreased glucose uptake, leading to decreased ATP production.
