antihelminths/antiprotozoals Flashcards
Albendazole (Albenza®) MOA
~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
Albendazole (Albenza®) SEs
- GI: N/V/D/abd. pain
- Teratogenic
- hepatotoxicity, increases in liver enzymes (~16 % of patients) -do LFTs
- Leukopenia (
Pyrantel (Antiminth®, Pin-X®)
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
Pyrantel (Antiminth®, Pin-X®) SEs
- GI: N/V/cramps
- CNS: ha, dizziness, drowsiness
- caution w. pre-ex. hepatic failure
- Use in pregnancy only when needed; Use in children
Praziquantel (Biltricide®)
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)
Praziquantel (Biltricide®)
- 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
Metronidazole (Flagyl®)
-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
Metronidazole (Flagyl®) SEs
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Iodoquinol (Yodoxin®)
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Iodoquinol (Yodoxin®)
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Paromomycin (Humatin®)
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Nitazoxanide (Alinia®)
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Nitazoxanide (Alinia®)
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Paromomycin (Humatin®)
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know drugs and MOA
know spp best tx by drug
he will go over biology but will not be tested
preferred drugs for Enterobius vermicularis
most common helminth infection in US
Albendazole (Albenza)
Pyrantel (Antiminth, Pin-X)
-need strict personal hygiene control
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”))
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
Taenia solium (pork tapeworm) Taenia saginata (beef tapeworm)
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

Necator americanus
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
Entamoeba histolytica
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
Entamoeba histolytica tx
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
Giardia lamblia – Giardiasis
-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
Giardia tx
metronidazole
nitazosanide
Trichomonas vaginalis – trichomoniasis
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
Cryptosporidium parvum (Cryptosporidiosis)
GI protozoal infection, contaminated water
- affects liver, biliary system, pancreas, lymphatics, and lungs
- large amounts of watery diarrhea with vomiting, cramping and flatulence.
Crypto tx
Nitazoxanide
Paromomycin
