Brainscape's Knowledge GenomeTM

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


See full index

GI II Final > Pharmacology of GI Infections: Abx and Anti-parasite Drugs > Flashcards

Pharmacology of GI Infections: Abx and Anti-parasite Drugs Flashcards

1
Q

Antimicrobial agents that may induce C.diff diarrhea and colitis

A

Frequently associated drugs include:

Fluoroquinolones
Clindamycin
Cephalosporins (broad-spectrum)
Penicillins

[macrolides and TMX are occasionally associated; rarely associated are aminoglycosides, tetracylcines, metronidazole, and vancomycin

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

_____ is the preferred pharmacologic tx for severe C.diff infection

_____ is the equivalent which is utilized in mild C.diff infection, sometimes chosen if oral administration won’t work for the pt

A

Vancomycin; metronidazole

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

_____ is the agent of choice for recurrent C.diff infection because it spares many anaerobic colonic flora

A

Fidaxomicin (macrolide family)

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

Key drugs in tx of H.pylori

A

Omeprazole (PPI)
Metronidazole
Tetracycline
Bismuth subsalicylate

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

The therapeutic goals of entamoeba histolytica tx are to eliminate the invading trophozoites and eradicate intestinal carriage of the organism (luminal amebicides); what drugs are utilized to accomplish these goals?

A

To eliminate the invading trophozoites: metronidazole (drug of choice) or tinidazole (better tolerated)

Eradicate intestinal carriage of the organism: paromomycin or iodoquinol

Both metronidazole and tinidazole must be given with a luminal amebicide to ensure eradication of E.histolytica!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Asymptomatic carriers of entamoeba histolytica have cysts or trophozoites without internalized RBCs. How are these pts treated?

A

With luminal amebicide agents — paromomycin or iodoquinol

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

Iodoquinol is used as a luminal amebicide, it has no effect against extraintestinal organisms. It is a halogenated hydroxyquinoline with an unknown MOA.

What is unique about its pharmacokinetics and what are some adverse effects?

A

90% of the drug is retained in the intestine and excreted in feces

AEs = diarrhea, anorexia, N/V, abdominal pain, HA, rash, pruritis

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

What clinical feature differentiates G.lamblia from E.histolytica?

A

No blood in stool (no invasion of intestinal wall)

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

Pharmacologic agents utilized in G.lamblia

A

Tinidazole (first-line agent)

Nitazoxanide

Metronidazole (not FDA approved for this but sometimes used)

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

MOA of nitazoxanide

A

Inhibition of pyruvate-ferredoxin oxidoreductase enzyme (essential to anaerobic energy metab)

[prodrug of tizoxanide]

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

Adverse effects of nitazoxanide

A

Nausea, anorexia, flatulence, increased appetite, enlarged salivary glands, yellow eyes, dysuria, bright yellow urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Cryptosporidium parvum tx

A

Antidiarrheal agents: loperamide

Antimicrobial agents: nitazoxanide (preferred) or paromomycin

Fluid management

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

How does cryptosporidium parvum tx change depending on immune status?

A

The main goal in an immunocompromised pt is to restore immune function

HIV: antiretroviral therapy may need to be reduced, add nitazoxanide if needed

Other: reduce dose of immunosuppressant + nitazoxanide

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

How does infection with necator americanus and ancyclostoma duodenale initially begin? What are some clinical features?

A

Penetration of skin between toes — results in intense itching at site of penetration

Other effects: diarrhea, abdominal pain, weight loss, anemia

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

How does infection with ascaris lumbricoides initially begin? What are some clinical features?

A

Consumption of eggs in contaminated food

Clinical features = abdominal cramping, malnutrition, worm invasion

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

Most helminth infections are diagnosed by presence of eggs in stool. How is Strongyloides stercoralis diagnosed?

A

Since Strongyloides eggs are not passed in the stool, it is diagnosed by larvae in feces or by enterotest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is strongyloides stercoralis infection started? What are some clinical features?

A

Larvae in soil penetrate human skin and travel to lungs —> coughed up and swallowed

Mature worms form in small intestine and release eggs

Clinical features: vomiting, abdominal bloating, diarrhea, anemia, weight loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why must you always check for strongyloides stercoralis in asthmatic patients when in endemic areas?

A

Patients with asthma may be on prednisone, which has immunosuppressive action that can lead to severe autoinfection with Strongyloides stercoralis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is unique about the lifecycle of trichuris trichiuria (whipworm)?

A

No larvae, no transit through intestinal wall, no lung involvement, no eosinophilia, no autoinfection

Simple life cycle with ingestion of food with infective eggs

20
Q

Diagnostic feature of trichuris trichiura

A

Football shaped eggs seen in feces

21
Q

Life cycle and features of enterobius vermicularis (pinworm) infection

A

Eggs ingested, pinworms mature in cecum and ascending large intestine

Female migrates to perianal area to lay eggs —> severe perianal itching and potential for hand to mouth transmission

Dx by scotch tape test; do not cause eosinophilia

22
Q

Drugs in general used to treat nematode infections

A 
Albendazole
Mebendazole
Ivermectin
Thiabendazole
Pyrantel pamoate
23
Q

MOA of albendazole and mebendazole

A

Inhibition of microtubule synthesis —> paralyzes worms which are then passed stool

Prodrug is turned into active metabolite after first pass effect

24
Q

The MOA of thiabendazole is the same as albendazole and mebendazole, but what is different about this drug?

A

Rapidly absorbed after ingestion, largely excreted in urine, and can be absorbed from the skin

MUCH MORE TOXIC than albendazole and mebendazole —> dizziness, anorexia, nausea, vomiting

Less common effects include irreversible liver failure and fatal Stevens-Johnson syndrome

25
Q

MOA of Ivermectin

A

Intensifies GABA-mediated transmission of signals in peripheral nerves of the nematode

26
Q

Pharmacokinetics and adverse effects of ivermectin

A

Rapidly absorbed, oral only, wide distribution, excretion in feces

Adverse effects are uncommon; this drug should not be combined with other drugs that enhance GABA activity (barbiturates, benzodiazepines, valproic acid, etc)

27
Q

MOA of pyrantel pamoate

A

Neuromuscular blocking agent, causes release of ACh and inhibits cholinesterase —> paralysis and expulsion of nematode

28
Q

Pharmacokinetics and AEs of pyrantel pamoate

A

Poorly absorbed from GI tract, half of administered dose is recovered unchanged in feces

AEs are infrequent and transient

29
Q

What is the primary drug of choice to treat infection with N.americanus or A.duodenale?

A

Albendazole

[alternate options: mebendazole, pyrantel pamoate]

30
Q

What is the primary drug of choice to treat infection with A.lumbricoides?

A

Albendazole or Mebendazole

[alternate: ivermectin]

31
Q

What is the primary drug of choice to treat infection with S.stercoralis?

A

Ivermectin

[alternate: albendazole]

32
Q

What is the primary drug of choice to treat infection with T.trichiura?

A

Mebendazole

[alternate: albendazole then ivermectin]

33
Q

What is the primary drug of choice to treat infection with E.vermicularis?

A

Albendazole OR Mebendazole OR Pyrantel Pamoate

[all considered primary options]

34
Q

Which of the parasites invades the venous system through exposed skin and maintains the ability to survive and release eggs for years due to molecular mimicry?

A

Schistosoma spp. (blood flukes)

Considered Trematodes

35
Q

Clinical manifestations of Schistosoma spp. infection

A

Dermatitis (immediate), Katayama fever including fever, hives, HSM, and bronchospasm (4-8 weeks in), chronic fibrosis (years)

36
Q

Drug of choice for tx of Schistosoma spp. Infection

A

Praziquantal (effective against Schistosoma spp. and most other trematode and cestode infections)

37
Q

MOA of Praziquantel

A

Increases permeability of nematode and cestode cell membranes to calcium —> paralysis, dislodgement, and death

38
Q

Pharmacokinetics and AEs associated with praziquantel

A

Oral administration, rapid absorption, renal excretion

AEs: Immediate — headache, dizziness, drowsiness, lassitude; after several days — low-grade fever, pruritis, rash

39
Q

Taenia solium and Taenia saginata are acquired by ingestion of undercooked meat containing larvae. What are some differences between the two?

A

T.solium = undercooked pork; attaches via hooks

T.saginata = undercooked beef; attaches via suckers

Both clinically manifest as weight loss and malnutrition

40
Q

Which parasite is acquired by ingestion larvae in raw freshwater fish, exhibits few abdominal symptoms, and absorbes vitamin B12 causing anemia?

A

Diphyllobothrium latum

41
Q

D.latum is dx by ___ and ___ in feces

A

Proglottids; eggs

42
Q

Echinococcus granulosus is an extraintestinal tapeworm infection caused by ingestion of eggs from dog feces. What is the main clinical feature seen w/ E.granulosus?

A

Hydatid cysts in the intestines — formed by larvae

43
Q

3 drugs used in tx of cestodes

A

Praziquantel
Niclosamide
Albendazole

44
Q

_____ is an alternative durg used for tx of most tape worm infections because it is not effective against hydatid cysts; its MOA is uncoupling of oxphos and blocking uptake of glucose causing death of the parasite

A

Niclosamide

[note: use also limited by side effects, long duration of therapy, and limited availability]

45
Q

Which parasites are considered Nematodes?

A 
Necator americanus
Ancyclostoma duodenale
Ascaris lumbricoides
Strongyloides stercoralis
Trichuris trichiura
Enterobius vermicularis
46
Q

Which parasites are considered platyhelmintes?

A

Trematodes (blood flukes):
Schistosoma

Cestodes (tapeworms):
Taenia solium
Taenia saginata
Diphyllobothrium latum
Echinococcus granulosus

GI II Final (8 decks)

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