8 Anti-Helmintics Flashcards
trematodes and cestodes are both considered flatworms but more specifically are
- trematodes= flukes
2. cestodes=tapeworms
what are the 3 groups of helminths
- nematodes= round worms
- trematodes= flat worms
- cestodes= flat worms
drugs for nematodes/roundworms
- albendazole
- pyrantel
- thiabendazole
- ivermectin
- diethylcarbamazine
albendazole is the DOC for–> nematodes/ roundworms=
- whipworms= Trichuris trichura
- pinworms= Enterobius vermicularis
- hookworms= Necator americanus
- round worms= Ascariasis lumbricoided
MOA for albendazole= vs. nematodes/round worms
binds to and interferes with microtubules
decreases glucose uptake–> parasite being expelled in feces
where is albendazole metabolized
liver
if its pinworm…
give albendazole to everyone in the household–> treat everyone
pyrantel (vs. nematodes/roundworms) is good vs.
- round worms
- pinworms
- hookworms
BUT nowhere near as effective as albendazole
what is the issue with pyrantel
its OTC drug–> so pts can self-medicate
MOA pyrantel (for nematodes/roundworms)
depolarizing m. blocking agent
- -> its + parasites nicotinic receptors
- this paralyzes the worm which gets expelled by the hosts intestinal tract
pyrantel is…
not advised in preg women bc there has been no established safety
if you have pinworms, WHAT DO YOU DO?
treat the whole family and anyone that came in contact
side effects of pyrantel (nematodes)
- dizziness, headaches
- abd cramps, vomiting
- increased liver enzymes–>liver disease
use thiabendazole (nematodes/roundworms) vs.
- threadworms= strongyloides stercoralis
- cutaneous larvae migrans= creeping eruption
- early stages trichinosis= Trichinella spiralis
MOA of thiabendazole
similar to albendazole?
-interferes with synthesis of parasites microtubules and decreases glucose intake
side effects of thiabendazole
LIVER DAMAGE–> jaundice
-bad smelling urine
STEVEN-JOHNSON SYNDROME–> skin layers separate
would you give thiabendazole to preg women?
NO
ivermectin (nematode/roundworms)= DOC for
Onchocerca volvulus–> riverblindness/onchocerciasis
scabies
MOA of ivermectin (river blindness)
targets GABA a receptors= mostly everywhere
–>causes Cl influx–> hyperpolarization–> paralysis of worm–> expelled
characteristics of ivermectin (river blindness)
- doesnt cross BBB
- metabolized in liver
- poop out
side effects of ivermectin (river blindness<– nematode)
- dizziness
- diarrhea
- LEUKOPENIA= decreased leukocytes
if you rapidly start killing worms with ivermectin you will see…
worms in the whites of the eye= MAZZOTTI RXN
when would it be contraindicated to give a pt ivermectin
if the patient is taking
- benzos
- barbs
or if the pt is pregnant
Diethycarbamazine is the DOC for
treating filariasis= Wuchereria bancrofti
MOA of diethylcarbamazine
decrease the muscular activity of parasites
What drug would you use for a trematode (flatworm–> fluke) infections
praziquantel
Praziquantel is the DOC for
- schistosomiasis
- trematodes= flatworms–> flukes
- cestode (flatworms–> tapeworms) infections= cysticercosis
MOA of praziquantel (used for trematodes and cestodes)
increase permeability of cell membrane to calcium
–> contracture and paralysis of parasite
which antihelminth has significant 1st pass effect
praziquantel–> for trematodes and cestodes
-also metabolized by the liver
contraindications for praziquantel
- dont give to preg women
2. dont use with cimetidine= p450 –> will increase plasma levels of praziquantel
what else can praziquantel be used for?
cestodes= tapeworms
- beef tapeworm
- pork tapeworm
- fish tapeworm
SOUNDS LIKE CHINESE BUFFET
how are trematodes and cestodes similar
they both lack a mouth and digestive tract
praziquantel is the DOC for trematodes and cestodes in the US but in other countries the DOC for cestodes/tapeworms is…
niclosamide–> which - parasites mitochondrial anaerobic phosphorylation (uncouples the rxn from ADP to ATP
what do you have to do before administering niclosamide
administer laxative prior to oral administration to purge bowel of dead segments
AVOID ALCOHOL W/I 1 DAY OF ADMINISTRATION OF DRUG
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