antihelminthic drugs

Question 1

taenia saginata

Answer 1

beef tapeworm, global, undercooked meat, cysticercosis

Question 2

taenia solium

Answer 2

pork tapeworm, global, uncooked pork, cysticercosis

Question 3

diphyllobothrium latum

Answer 3

largest tapeworm, undercooked fish, robs host of B12, northern hemisphere

Question 4

schistosomiasis

Answer 4

schisosoma hematobium, mansoni, japonicum
symptoms due to immune reaction to egg - headaches, fatigue, fever, gastrointestinal problems, hepatic fibrosis, ascites, bladder cancer

Question 5

praziquantel use against

Answer 5

against flatworms (cestodes and trematodes), no action against nematodes

Question 6

praziquantel mechanism of action

Answer 6

disrupts clacium homeostasis, muscular contraction and spastic paralysis, worms dislodge and die

Question 7

praziquantel dosing

Answer 7

two or three doses for schistosomiasis

single doses for T. saginata, solium and D. latum (doesn’t kill eggs of T. solium)

Question 8

praziquantel toxicity

Answer 8

reaction to dying worms, avoid if pregnant, dizziness and drowsiness (avoid driving)

Question 9

american hookworm

Answer 9

necator americanus, nematode

Question 10

old world hookworms

Answer 10

ancylostoma doudenale, nematode

Question 11

hookworm infection

Answer 11

found in soil
infect by penetrating through skin or oral ingestion
feed on intestinal tissue and blood
live up to 15 yrs
pulmonary lesions, skin reactions, intestinal ulcerations, anemia

Question 12

pinworms - nematode

Answer 12

enterobiasis, widespread in temperate (US)
live in GI, migrate to rectum to lay eggs, causes perianal pruritis, eggs infect fingers/sheets, ingestion of eggs cause new infection cycle

Question 13

roundworms - nematode

Answer 13

ascariasis
developing countries 
reside in small intestine
penetrate intestinal wall, transported to lungs, trachea and reswallowed
poor sanitation

Question 14

whipworm

Answer 14

trichuriasis
subtropics, SE USA
ingesting eggs in contaminated food/liquids
eggs passed in feces, reside in large intestine, 5 cm length
live 5 years in host
irritation, inflammation of colonic mucosa, abdominal pain diarrhea, distension

Question 15

trichinella spiralis (nematode) causes

Answer 15

trichinosis - diarrhea, abdominal pain, nausea, muscle pain, edema, weakness 
infection can be intestinal and systemic
undercooked pork (feeding on untreated garbage)
first round of replication in intestines
progeny distributed throughout body

Question 16

filariasis

Answer 16

lymphatic dwelling filaria, elephantiasis, transmitted by mosquitoes

Question 17

organisms causing filariasis

Answer 17

nematodes: wuchereria bancrofti (tropical), brugia malayi (asia), brugia timori (indonesia)

Question 18

eyeworm

Answer 18

loa loa, transmitted by deer flies, often asymptomatic, ocular lesions can cause blindness, africa

Question 19

river blindness

Answer 19

onchocerca volvulus, transmitted by female blackflies, africa, blindness, dangerous and infects millions in africa/some areas uninhabitable

Question 20

types of benzimidazoles

Answer 20

mebendazole, thiabendazole, albendazole

Question 21

benzimidazoles mechanism

Answer 21

binds to tubulin, inhibits formation of microtubules

Question 22

benzimidazoles pharmacokinetics

Answer 22

poorly absorbed in GI, fatty meal increases absorption
luminal parasites - empty stomach
tissue infections - with fatty meal

Question 23

albendazole

Answer 23

converted to sulfoxide form - active metabolite
well tolerated in short term treatments
drug of choice for cysticercosis
also used for pinworms, hookworms, ascariasis, trichuriasis, strongyloidiasis

Question 24

mebendazole

Answer 24

metabolites not active 
well tolerated in short term treatments
teratogenic 
pinworms, hookworms, ascariasis, trichuriasis (whipworm)
strongyloidiasis

Question 25

thiabendazole

Answer 25

no longer prefered - toxicity (dizziness, anorexia, nausea, vomiting, should not be used in pregnant women) metabolites not active

Question 26

diethylcarbamazine

Answer 26

filariasis and loiasis microfilariae rapidly killed well absorbed from GI well tolerated but reactions to dying worms can be severe systemic inflammation from release of bacterial endosymbiont

Question 27

ivermectin

Answer 27

strongyloidiasis, primarily onchocerciasis (single dose) mass treatment programs - once a year, treat for lifespan of adult worm semisynthetic macrocyclinc lactone good oral availability

Question 28

ivermectin mechanism of action

Answer 28

paralyzes microfilariae, allows host cytotoxic cells to adhere doesnt kill adult worms, blocks release of progeny intensifies gaba-mediated transmission of signals to peripheral nerves in worm affects similar channels in mammalian brain but requires 100-fold higher concentration

Question 29

pyrantel pamoate

Answer 29

OTC broad spectrum antihelminth highly effective for pinworms and ascaris moderately effective for hookworms against adult and immature worms (not against migratory stages or ova)

Question 30

pyrantel pamoate mechanism of action

Answer 30

neuromuscular blocking agent, release of acetylcholine and inhibits cholinesterase - worms paralyzed and expelled

Question 31

pyrantel pamoate - ascariasis

Answer 31

one dose 11mg/kg, 85-100% effective

Question 32

pyrantel pamoate - pinworms

Answer 32

two doses, two weeks apart, 95% cure rate

Question 33

scabies

Answer 33

itch from female burrowing feces | treat with 5% permethrin cream, may need to soften skin/bites with salicylic acid first

Question 34

lice treatment

Answer 34

1% permethrin or pyrethrin, 2nd application 10 days later | spinosad - newer

Question 35

trichinosis treatment

Answer 35

mebendzole plus corticosteroids