Anti-Helminthics

Question 1

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.

Answer 1

Albendazole

Question 2

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.

Answer 2

Albendazole

Question 3

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.

Answer 3

Albendazole

Question 4

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

Answer 4

Albendazole

Question 5

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.

Answer 5

Mebendazole

Question 6

Physiologic disposition- poorly absorbed. Used for GI tract infections.

Answer 6

Mebendazole

Question 7

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.

Answer 7

Mebendazole

Question 8

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

Answer 8

Mebendazole

Question 9

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.

Answer 9

Ivermectin

Question 10

Physiologic disposition- readily absorbed, 1/2 life 57 hours, metabolized by CYP3A4

Answer 10

Ivermectin

Question 11

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.

Answer 11

Ivermectin

Question 12

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.

Answer 12

Ivermectin

Question 13

MOA- depolarizing neuromuscular blocker causing spastic paralysis. 1) stimulates nicotinic receptor 2) increase in ACh release and spastic paralysis. MOR- typically not a problem.

Answer 13

Pyrantel pamoate

Question 14

physiologic disposistion- poorly absorbed. Eliminated in feces.

Answer 14

Pyrantel pamoate

Question 15

used against luminal parasites (nematodes)
Pinworm
Ascaris
Trichostrongylus orientalis
Kills larvae and adults but not eggs.

Answer 15

Pyrantel pamoate

Question 16

AE/Toxicities- typically not a problem. Transient mild GI, HA. At high doses can cause neuromuscular blockade in host.

Answer 16

Pyrantel Pamoate

Question 17

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.

Answer 17

Diethylcarbamazine (DEC)

Question 18

physiologic disposition- rapidly absorbed. T1/2 2-10hrs. Renal excretion.

Answer 18

Diethylcarbamazine (DEC)

Question 19

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.

Answer 19

Diethylcarbamazine (DEC)

Question 20

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.

Answer 20

Diethylcarbamazine (DEC)

Question 21

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.

Answer 21

Praziquantal

Question 22

Physiologic disposition- readily absorbed. T1/2

Answer 22

Praziquantal

Question 23

used against trematodes and cestodes. Drug of choice for all schistosomiasis species. Not good against nematodes.

Answer 23

Praziquantal

Question 24

AE/Toxicities- abdominal discomfort, HA, dizzy, drowsy.
CI- pregnancy.
Decrease dose with hepatic disease.
CI- intraocular cysticercosis- caused by larval pork tapeworm.

Answer 24

Praziquantal