Pharm - GI Infections Flashcards Preview

Maddy - GI II Exam I - some pharm > Pharm - GI Infections > Flashcards

Flashcards in Pharm - GI Infections Deck (53)
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1
Q

compare effects of toxin A and toxin B in c. diff

A

toxin A: diarrhea

toxin B: cytotoxic to colonic cells

2
Q

what are the antibiotics frequently associated with c. diff

A
  • fluoroquinolones
  • clindamycin
  • later gen cephalosporins
  • later gen penicillin
3
Q

preferred tx for severe, mild, and recurrent c. diff infection

A

severe: vancomycin
mild: metronidazole
recurrent: fidaxomicin

4
Q

compare administration b/w vancomycin and metronidazole when treating c. diff

A

vancomycin: oral
metronidazole: IV or oral; used if oral administration won’t work

5
Q

what are the families of the three main drugs used to treat c. diff

A

vancomycin: glycopeptide
metronidazole: 5-nitroimidazole
fidaxomicin: macrolide

6
Q

when treating e. histolytica, what are the drugs used to:

1) eliminate invading trophozoites
2) eradicate intestinal carriage of the organism

A

eliminate invading trophozoites: metronidazole or tinidazole

eradicate intestinal carriage of organism: paromomycin or iodoquinol

7
Q

how to treat asymptomatic carriage of e. histolytica

A

luminal amebicide

8
Q

what is the drug of choice for extraluminal amebiasis with e. hystolytica

A

metronidazole

9
Q

what must you give with metronidazole or tinidazole when eradicating e. histolytica

A

luminal amebicide

10
Q

adverse effects iodoquinol

A

diarrhea, anorexia, N/V, abd pain, HA, rash, pruritis

11
Q

what is iodoquinol used for and why

A

used as a luminal amebicide

- 90% retained in intestine and excreted in feces, so good for treating intraintestinal organisms

12
Q

what families are paromomycin and iodoquinol in

A

paromomycin: aminoglycoside
iodoquinol: 8-hydroxyquinolines

13
Q

first line agent for treating giardia lamblia

- 2nd and 3rd line agents

A

first line: tinidazole

then nitazoxanide and metronidazole

14
Q

MOA nitazoxanide

A

inhibition of pyruvate-ferredoxin oxidoreductase enzyme (which is essential to anaerobic energy metabolism)
- it’s a prodrug

15
Q

adverse effects nitazoxanide

A

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

16
Q

what antidiarrheal and antimicrobial agents are used to treat cryptosporidium parvum

A

antidiarrheal: loperamide
antimicrobial: nitazoxanide (preferred) and paromomycin

17
Q

compare treatment for cryptosporidium parvum between HIV patients and otherwise-immunocompromised patients

A

HIV: antiretroviral therapy + nitazoxanide

other: reduce dose of immunosuppressant + nitazoxanide

18
Q

diagnosis for nematodes requires ______

A

visualization of microscopic eggs in feces

19
Q

describe life cycle of necator americanus and ancylostoma duodenale (hook worms)

A

penetrates skin in between toes –> larvae travel to lungs –> coughed up and swallowed –> adult worms develop in small intestine –> worms repopulate and release eggs –> eggs excreted in feces –> eggs hatch and larvae live in soil

20
Q

describe the life cycle of ascaris lumbricoides

A

consumption of eggs in contaminated food –> larvae penetrate intestine and travel to lung –> coughed up and swallowed –> adult worms develop in small intestine –> worms release eggs –> eggs excreted in feces –> eggs hatch and larvae live in soil

21
Q

describe the life cycle of strongyloides stercoralis

A

larvae in soil penetrate human skin –> travels to lungs –> coughed up and swallowed –> mature worms form in small intestine and release eggs –> eggs hatch in intestine (EGGS DO NOT PASS IN STOOL) –> larvae can autoinfect, excrete in feces and infect, or excrete in feces, mature, lay eggs, and new larvae infect

22
Q

what medications can lead to severe autoinfection with strongyloides stercoralis

A

immunosuppressive meds

- prednisone in asthma patients

23
Q

how to diagnose strongyloides stercoralis

A

larvae in feces and enterotest

24
Q

describe the life cycle of trichuris trichiura (whip worm)

A

ingestion of food with infective eggs –> eggs hatch in small intestine –> migrate to cecum and ascending large intestine –> mature adult produces thousands of eggs per day for 1 year

25
Q

how to diagnose trichuris trichiura (whip worm)

A

eggs in feces (football shaped)

26
Q

describe the life cycle of enterobius vermicularis (pinworm)

A

eggs ingested –> pinworms mature in cecum and ascending large intestine –> females migrate to perianal area at night to lay eggs

27
Q

what are the 5 nematode tx drugs

A

1) albendazole
2) mebendazole
3) thiabendazole
4) ivermectin
5) pyrantel pamoate

28
Q

MOA albendazole, mebendazole, and thiabendazole

A

inhibits microtubule synthesis which PARALYZES the worms which are then passed in the stool
- a prodrug

29
Q

compare adverse effects b/w thiabendazole and abendazole and mebendazole

A

thiabendazole is much more toxic, causes:

  • dizziness
  • anorexia
  • N/V
  • can cause irreversible liver failure and stevens johnson syndrome
30
Q

MOA ivermectin

A

intensifies y-aminobutyric acid (GABA)-mediated transmission of signals in peripheral nerves of the nematode –> causing PARALYSIS

31
Q

administration of ivermectin

A

oral only

32
Q

MOA pyrantel pamoate

A

neuromuscular blocking agent causing release of ACh and inhibition of cholinesterase –> causing PARALYSIS

33
Q

pharmacokinetics pyrantel pamoate

A

poorly absorbed in GI tract (stays in GI), half of administered dose recovered unchanged in feces

34
Q

primary, alternative, and poor choice of drugs to treat N. americanus and A. duodenale

A

primary: albendazole
alternative: mebendazole or pyrantel pamoate
poor: ivermectin

35
Q

primary and alternate tx for A. lumbricoides

A

primary: albendazole or mebendazole
alternate: ivermectin

36
Q

primary and alternate tx for S. stercoralis

A

primary: ivermectin
alternate: albendazole

37
Q

primary, alternate, and second alternate tx for T. trichiura

A

primary: mebendazole
alternate: albendazole

second alternate: ivermectin

38
Q

primary tx for E. vermicularis

A

primary: albendazole, mebendazole, and pyrantel pamoate

39
Q

how to schistosoma mansoni trematodes infect

A

invade venous system through exposed skin

- eggs must reach fresh water to hatch

40
Q

describe geographic distribution of S. japonicum, S. mansoni, and S. haematobium (schistosoma spp)

A

S. japonicum: east asia

S. mansoni: south america and africa

S. haematobium: africa

41
Q

describe where the organisms reside in S. japonicum, S. mansoni, and S. haematobium (schistosoma spp)

A

S. japonicum: intestinal tract

S. mansoni: intestinal tract

S. haematobium: bladder

42
Q

describe where the organism deposits eggs in S. japonicum, S. mansoni, and S. haematobium (schistosoma spp)

A

S. japonicum: feces

S. mansoni: feces

S. haematobium: urine

43
Q

describe the life cycle of schistosoma spp. (blood flukes)

A

eggs hatch in fresh water –> larvae infect and mature within a snail –> mature larvae leave snails and infect humans through exposed skin –> mate in intrahepatic portion of portal venous system –> migrate to veins surrounding intestine or bladder to lay eggs –> eggs enter lumen of intestine or bladder

44
Q

tx of choice for schistosoma

A

praziquantel

45
Q

MOA praziquantel

A

increases permeability of nematode and cestode cell membranes to calcium –> cause PARALYSIS

46
Q

adverse effects praziquantel

A

immediate: HA, dizziness, drowsiness (all from drug)

after several days: low grade fever, pruritis, skin rash (all from dead worm)

47
Q

describe life cycle of Taenia solium and Taenia saginata

A

pigs/cows ingest egg from field contaminated by human feces –> larvae disseminate through intestine into muscle –> larvae develop into cysticerci –> human ingests undercooked meat –> tapeworm matures in intestine

48
Q

compare T. solium and T. saginata in how they infect

A

T. solium: hooks

T. saginata: suckers

49
Q

life cycle of diphyllobothrium latum

A

adult tape worm in human ingestion excretes proglottids w/ eggs –> eggs hatch in water and convert to motile larvae –> ingested by human

50
Q

how does echinococcus granulosus infect

A

humans ingest eggs from dog feces –> eggs hatch in intestine and larva form hydatid cysts

51
Q

tx for cestodes (tapeworms)

A

praziquantel, niclosamide, albendazole

52
Q

MOA niclosamide

A

uncouples oxidative phosphorylation, blocking uptake of glucose –> results in DEATH of parasite

53
Q

why is niclosamide an alternative tx for tapeworms

A

it is not effective against hydatid cysts