Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology > Antihelminthic > Flashcards

Antihelminthic Flashcards

1
Q

What are some unique characteristics of parasitic infections?

A

Worms multiply outside of their definitive host in contrast to other parasites
Evade immune system
Infections are chronic - last lifetime of the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What parasite has the high infection rate in the world?

A

Ascaris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where are anthropod-borne parasites endemic?

A

tropic and pets in the USA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two phyla?

A

Flatworms (Platyhelminths) - Tapeworms (Cestodes), Flukes and Schistosomes (Trematodes)
Roundworms (Nematodes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are examples of tapeworm infections?

A 
Beef Tapeworm (Taenia saginata)
Pork Tapeworm (Taenia solium)
Fish Tapeworm (Diphyllobothrium latum)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Facts about T. saginata - cestode

A

Global distribution

Transmitted by eating undercooked meat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Facts about T. solum - cestode

A

Global distribution
Bladder worms
Occasionally found in undercooked pork

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Facts about D. latum - cestode

A

Largest tapeworm (10m)
Transmitted by eating undercooked fish
Northern hemisphere
Robs host of nutrients, especial vit. B12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Life cycle of Taenia

A

Eggs/proglottids pass into environment –> cattle or pig become infected by eating contaminated vegetation –> oncospheres hatch –> penetrate intestinal wall –> circulate to musculature –> oncospheres develop into cysticerci in muscle –> human infected by eating raw or undercooked meat –> taenia use scolex to attack to intestine –> mature into adults –> release proglottids into feces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is cysticercosis

A

caused by autoinfection by ingesting eggs produced by T. solium
can go to the brain (instead of the muscle) and cause neurocysticercosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is Dwarf Tapeworm - cestode

A 
Hymenolepis nana
most common cestode infection 
can be transmitted directly between humans
found in temperate regions worldwide
children predominately infected 
infected by ingesting eggs
generally not serious
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is schistosomiasis - trematode

A

Bloodflukes
3 species: S. hematobium; S. mansoni; S. japonicum
Caribbean, S. America, Africa, Middle East
Can live for 5-10 yrs
Sx due to immune reaction to eggs (headaches, fatigue, fever, GI problems, ascites, hepatic fibrosis, bladder cancer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Praziquantel used for?

A

Highly effective against cestodes and trematodes
No activity against nematodes
MOA: disrupt calcium homeostasis, causes muscular contraction followed by spastic paralysis, immune response may be involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Praziquantel therapeutic uses

A

Drug of choice for all schistosomiasis
dramatically reduces egg burden in those not cured
Single does kills 100% of saginata, solium, and latum
DOES NOT KILL EGGS OF SOLIUM
Toxicity: mild and transient, avoid in pregnancy, and avoid driving(dizziness/drowsiness)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Facts about Hookworms

A

American hookworm (Necator americanus)
Old world hookworm (Ancyclostoma duodenale)
Found in soil
Infect by penetrating through the skin or ingestion
feed on intestinal tissue and blood
Cause pulmonary lesions, skin reactions, intestinal ulcerations, and anemia
Prevalent in regions w/ temp around 23-33C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Facts about Pinworms - Nematode

A

Enterobiasis
widespread in temperate regions
most common worm infection in US (household and institutions)
Live in GI tract: females migrate to rectum at night to deposit eggs
Causes perianal pruritus
Eggs infect fingers and bed sheets (infective for 3 wks)
INGESTION OF EGGS STARTS NEW LIFE CYCLE

17
Q

Facts about Roundworms - nematodes

A 
Ascariasis 
Common in developing countries 
Resides in small intestine
Life cycle: Ingest eggs --> larva hatch in small intestine --> penetrate intestinal wall --> transported to lungs --> after 10 days pass through lungs to trachea --> re-swallowed --> return to small intestine 
Associated with poor sanitation
18
Q

Facts about Whipworm infections - nematode

A

Trichuriasis
Infections are common in tourists who visit the subtropics and S.E US
Caused by ingesting eggs in contaminated food or liquid
Eggs are passed in feces
Reside in large intestine
Cause irritation and inflammation of colonic mucosa, abdominal pain. diarrhea, and distention

19
Q

Facts about Trichinosis - nematode

A

Trichina
Caused by Trichinella spiralis
Infection can be intestinal and systemic
Associated with undercooked pork (also wild boar, bear, and walrus)
Initial round of replication is in intestines
Progeny are distributed throughout the body

Cause diarrhea, abdominal pain, nausea (intestinal stage)
and muscle pain, edema, and weakness (muscular stage)

20
Q

Facts about Filariasis

A 
lymphatic dwelling filaria include:
Wuchereia bancrofti - tropical regions worldwide
Brugia malayi - Asia 
Brugia timori - Indonesia 
Transmitted by mosquitos
Cause elephantiasis
21
Q

What is Loa Loa

A 
Eyeworm 
transmitted by deer flies 
often asymptomatic 
ocular lesions can cause blindness
Primarily found in Africa
22
Q

What is River blindness

A

Onchocerca volvulus
Transmitted by female blackflies
Renders parts of Africa uninhabitable
750,000 blinded/impaired

23
Q

What is the reasonable goal of Tx:

A

reasonable goal is to reduce the burden of infection

24
Q

What drugs are used to treat helminth infections:

A 
Diethylcarbamazine 
Ivermectin
Mebendazole or Albendazole 
Praziquantel 
Pyrantel Pamoate
25
Q

What are benzimidazoles

A

broad spectrum activity
Ex: mebendazole, thiabendazole, albendazole
Thiabendazole most toxic
MOA: binds to tubulin; inhibits formation of microtubules by capping them
Are able to bind to mammalian tubulin

26
Q

What are the pharmacokinetics of benzimidazoles

A

poorly absorbed in the GI tract (fatty meal can increase absorption)
luminal parasites –> empty stomach
tissue infections –> admin with fatty meal

Rapidly metabolized in liver
Albendazole –> sulfoxide form (active)
Metabolites of mebendazole and thiabendazole are NOT ACTIVE

27
Q

Toxicity of benzimidazoles

A

albendazole and mebendazole well tolerated in short-term treatments
thiabendazole more toxic (dizziness, anorexia, nausea, committing, don’t give during pregnancy)
mebendazole is teratogenic (not used in pregnant women)

28
Q

Therapeutic uses of benzimidazoles

A

Albendazole is the drug of choice for cysticercosis (also for pinworms, hookworms, ascariasis, trichuriasis, and strongyloides)

Mebendazole used for pinworms, hookworms, ascariasis, and trichuriasis

Thiabendazole NO LONGER preferred due to toxicity

29
Q

What is diethylcarbamazine?

A

MOA unknown
Drug of choice for filariasis and loiasis (elephantiasis and eye worm)
microfilariae are rapidly killed; adults are killed slowly
must be careful in high burden (Mazzotti rxn)
well absorbed in GI tract
Generally well tolerated
reaction to dying worms can be severe –> may lead to systemic inflammation from release of bacterial endosymbiont –> Tx with Doxy

30
Q

What is Ivermectin?

A

Drug of choice for strongyloidiasis and onchocerciasis (river blindness)
good oral availability
semisynthetic macrocyclic lactone
MOA: paralyzes microfilariae; intensifies GABA-mediated transmission of signals in peripheral nerves
allows host cytotoxic cells to adhere
Does not kill adult worms
Block release of progeny
affects similar channels in mammalian brain but requires higher concentration –> therefore selective only for parasite

31
Q

What are the therapeutic uses of Ivermectin

A

primarily used for onchocerciasis
single dose
Tx must be continues for lifespan of adult worm
Can also be used in Pets (many collies)?

32
Q

What is pyrantel pamoate

A

broad spectrum antihelminth
available OTC
bioavailability extremely low, acts in gut
highly effective for treatment of PINWORMS and ASCARIS
moderately effective against hookworms
active against adult and immature worms (not against migratory stages or ova)

33
Q

What is the MOA and Clinical uses of Pyrantel pamoate

A

MOA: neuromuscular blocking agent
causes release of Ach and inhibition of cholinesterase
worms are paralyzed and expelled

Clinical uses: Ascaris - 1 dose; Pinworms- drug of choice - 2 doses 2 weeks apart

34
Q

What drug is used for Trichinosis

A

Mebendazole + corticosteroids

35
Q

What drug is used for Strongyloidiasis

A

Mebendazole or albendazole

36
Q

What drug is used for Onchocerciasis

A

Ivermectin

37
Q

What drug is used for Filariasis

A

Diethylcarbamazine

Pharmacology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions