antihelminths/antiprotozoals

Question 1

Albendazole (Albenza®) MOA

Answer 1

~5% absorbed orally

• Bind with high affinity to free β-tubulin of the parasite–>inhibition of microtubule polymerization and an inhibition of microtubule-dependent glucose uptake (good selectivity, does not bind well to human β–tubulin)
• txs GI and systemical symptoms

Question 2

Albendazole (Albenza®) SEs

Answer 2

• GI: N/V/D/abd. pain
• Teratogenic
• hepatotoxicity, increases in liver enzymes (~16 % of patients) -do LFTs
• Leukopenia (

Question 3

Pyrantel (Antiminth®, Pin-X®)

Answer 3

Broad-spectrum OTC drug that is effective against a variety of nematodes
*activation of cholinergic nicotinic recs in the muscles of the nematode resulting in a depolarizing NM blockade–>worm becomes paralyzed (similar to succinylcholine in humans) and is expelled from the GIT during peristalsis

Question 4

Pyrantel (Antiminth®, Pin-X®) SEs

Answer 4

• GI: N/V/cramps
• CNS: ha, dizziness, drowsiness
• caution w. pre-ex. hepatic failure
• Use in pregnancy only when needed; Use in children

Question 5

Praziquantel (Biltricide®)

Answer 5

Broad spectrum drug with activity against shistosomes (trematodes) as well as tapeworms (cestodes), effective against neuroschistosomiasis

• ppx for travelers to endemic areas (Africa)
• induces muscle contraction then spastic paralysis of the musculature of worms by causing an increase in calcium ion influx–>With cestodes, this action causes the suckers to become dislodged. (good selectivity; little effect on human muscle)

Question 6

Praziquantel (Biltricide®)

Answer 6

• CNS: dizziness, drowsiness, headache, decreased mental alertness
• GI: N/V/abd. pain
• hepatic: inc. liver enzymes
• urticaria, rash, low-grade fever, arthralgia, myalgia
• Avoid with pregnancy if possible

Question 7

Metronidazole (Flagyl®)

Answer 7

-good oral absorption, only used if symptomatic: GI, amebic liver abscess
MOA: cidal, drug gets reduced and binds to IC macromolecules (e.g. DNA)–>inhibition of DNA synthesis
-anaerobic bac: B. fragilis, C. diff
-protozoa: E. histo, Trich vag*, Giardia
*resistance

Question 8

Metronidazole (Flagyl®) SEs

Answer 8

?

Question 9

Iodoquinol (Yodoxin®)

Answer 9

?

Question 10

Iodoquinol (Yodoxin®)

Answer 10

?

Question 11

Paromomycin (Humatin®)

Answer 11

?

Question 12

Nitazoxanide (Alinia®)

Answer 12

?

Question 13

Nitazoxanide (Alinia®)

Answer 13

?

Question 14

Paromomycin (Humatin®)

Answer 14

?

Question 15

know drugs and MOA

Answer 15

know spp best tx by drug

he will go over biology but will not be tested

Question 16

preferred drugs for Enterobius vermicularis

most common helminth infection in US

Answer 16

Albendazole (Albenza)
Pyrantel (Antiminth, Pin-X)
-need strict personal hygiene control

Question 17

preferred drugs for Ascaris lumbricoides

(2nd most common helminth inf. in US, most common WW, only inf. humans, egg is resistant (“night soil”, “wandering worms”))

Answer 17

2nd most common helminth inf. in US, most common WW, only inf. humans, egg is resistant (“night soil”)
Asymptomatic or mild infections: albendazole
Heavy infections: pyrantel (sx may be required i.e. if reach common bile duct), causes more paralysis, reduces wandering

Question 18

Taenia solium (pork tapeworm) Taenia saginata (beef tapeworm)

Answer 18

Helminth: Cestodes: (Tapeworms)
Adult worms can cause GI upset, loss of appetite, and larvae (cysticerci) can become encysted in visceral organs causing the disease cysticercosis (T. solium)
both tx w. Praziquantel (Biltricide)
T. solium tx may cause the disintegration of gravid segments of T. solium that can result in the release of embryos from the eggs and cysticercosis; give a purgative (magnesium sulfate 15 to 30 g) 2 hrs after praziquantel tx


Question 19

Necator americanus

Answer 19

Helminth: Nemotode: hookworm, feed on blood, cause iron-def. anemia (mental dullness)
-inf. thru skin (foot), don’t need to eat
Albendazole: also tx “creeping eruptions” as parasite moves under skin

Question 20

Entamoeba histolytica

Answer 20

Amebiasis; 1 – 5% USA; 10 % World’s population

• ingest cysts, typ. contaminated water, oral-anal contact
• cause sev. bloddy diarrhea, may spread to liver and cause hepatic abscess

Question 21

Entamoeba histolytica tx

Answer 21

asymptomatic carrier tx: (Luminal acting drugs):
iodoquinol, paramomycin

symtomatic tx: (e.g. gastrointestinal symptoms, amebic liver abscess) Tissue Amebicide + Luminal acting drugs:
Metronidazole followed by Iodoquinol or Paromomycin

Question 22

Giardia lamblia – Giardiasis

Answer 22

-Most commonly reported pathogen for causing infectious diarrhea in US
-contaminated water, sexual practices, poor hand washing
-causes profuse watery foul-smelling Diarrhea, abd. distension and cramping,
anorexia and nausea, constipation

Question 23

Giardia tx

Answer 23

metronidazole

nitazosanide

Question 24

Trichomonas vaginalis – trichomoniasis

Answer 24

5 - 10% in women in the general population; 50
– 70% in prostitutes
-sexually transmitted, treat the sexual partner(s) of the
infected individual to prevent recurrence
tx: Metronidazole

Question 25

Cryptosporidium parvum (Cryptosporidiosis)

Answer 25

GI protozoal infection, contaminated water

• affects liver, biliary system, pancreas, lymphatics, and lungs
• large amounts of watery diarrhea with vomiting, cramping and flatulence.

Question 26

Crypto tx

Answer 26

Nitazoxanide

Paromomycin