Anti-Helminthics Flashcards
MOA - inhibits microtubule polymerization which inhibits mitosis and causes immobilization or death of parasite.
Inhibits energy production (inhibits glucose uptake) mitochondrial fumarate reductase and uncouples oxidative phosphorylation.
MOR - switches B-tubulin isotype. Point mutation in B-tubulin isotype 1.
Albendazole
Physiologic disposition- erratic variable absorption- enhanced by fatty food and bile salts. Rapid 1st pass metabolism to active metabolite, readily penetrates tissues and hydatid cysts (tapeworm larvae). Used for GI and systemic.
Albendazole
Used against nematodes- roundworm (Ascaris), pinworm (enterobius), whipworm (Trichuris), Hookworm (Necator), and Lymphatic filariasis (elephantitasis). Kills eggs and larvae, evidence it also kills adult worms.
Albendazole
Side Effects/Toxicities- When used for 1-3 days, very few SE. Longer term use can lead to bone marrow suppression, alopecia and liver abnormalities.
CI in pregnancy, safety in
Albendazole
MOA - inhibits microtubule polymerization which inhibits mitosis and causes immobilization or death of parasite.
Inhibits energy production (inhibits glucose uptake), mitochondrial fumarate reductase and uncouples oxidative phosphorylation.
MOR -Switches B-tubulin isotype. Point mutation in B-tubulin isotype 1.
Mebendazole
Physiologic disposition- poorly absorbed. Used for GI tract infections.
Mebendazole
Used against nematodes- roundworm (Ascaris), pinworm (enterobius), whipworm (Trichuris), Hookworm (Necator), and Lymphatic filariasis (elephantitasis). Kills eggs and larvae, evidence it also kills adult worms.
Mebendazole
AE/Toxicities- Short term/low dose therapy has few side effects. High dose therapy can cause bone marrow suppression, alopecia, and transient liver abnormalities.
CI in pregnancy, kids
Mebendazole
MOA - activates an invertebrate specific glutamate-gated Cl- channel which leads to flaccid paralysis (Microfilariae can no longer move or feed).
MOR - ATP-dependent P-glycoprotein transporter mediated drug efflux out of the cells in the parasite. OR Mutations in the ligand gated Cl- channel leading to decreased drug binding.
Ivermectin
Physiologic disposition- readily absorbed, 1/2 life 57 hours, metabolized by CYP3A4
Ivermectin
Used against nematode infections like onchocerciasis (African River Blindness), lymphatic filiarisis (Elephantiasis). Administered every 6-12 months for 5-10 years. NOT effective against trematodes and cestodes. Kills microfilariae.
Ivermectin
AE/Toxicities- usually well tolerated. Can have a severe immune response to the dying microfilariae. CI in pts with impaired BBB and LoaLoa infected patients.
Ivermectin
MOA- depolarizing neuromuscular blocker causing spastic paralysis. 1) stimulates nicotinic receptor 2) increase in ACh release and spastic paralysis. MOR- typically not a problem.
Pyrantel pamoate
physiologic disposistion- poorly absorbed. Eliminated in feces.
Pyrantel pamoate
used against luminal parasites (nematodes) Pinworm Ascaris Trichostrongylus orientalis Kills larvae and adults but not eggs.
Pyrantel pamoate
AE/Toxicities- typically not a problem. Transient mild GI, HA. At high doses can cause neuromuscular blockade in host.
Pyrantel Pamoate
MOA- Stimulates host immune response. Alters worm surface membrane resulting in enhanced killing by host immune system. Worm paralysis, organelle damage and apoptosis. and MOR- typically not a problem.
Diethylcarbamazine (DEC)
physiologic disposition- rapidly absorbed. T1/2 2-10hrs. Renal excretion.
Diethylcarbamazine (DEC)
used against nematode that causes LoaLoa, kills microfilariae and adults. Used in combo with albendazole against lymphatic filariasis.
Only available from the CDC or PDDS.
Diethylcarbamazine (DEC)
AE/Toxicities- Rarely severe if administered at standard doses.
Can have severe adverse reaction to host immune/inflammatory response to dying microfilariae or adult worms.
CI in onchocerciasis.
Diethylcarbamazine (DEC)
MOA - Quinolone derivative. Increased membrane permeability to Ca++. Increased influx of Ca++ across tegument and muscle cells leading to host immune response and spastic paralysis. MOR- not a problem.
Praziquantal
Physiologic disposition- readily absorbed. T1/2
Praziquantal
used against trematodes and cestodes. Drug of choice for all schistosomiasis species. Not good against nematodes.
Praziquantal
AE/Toxicities- abdominal discomfort, HA, dizzy, drowsy.
CI- pregnancy.
Decrease dose with hepatic disease.
CI- intraocular cysticercosis- caused by larval pork tapeworm.
Praziquantal
