Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GI II Exam 2 > Lecture 14: Pharm. of GI Infections: Antibiotic and Anti-Parasitic > Flashcards

Lecture 14: Pharm. of GI Infections: Antibiotic and Anti-Parasitic Flashcards

1
Q

What is the preferred tx for severe C. difficile infection?

i.e., first-line tx

A

Vancomycin (glycopeptide)

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

What is the preferred tx for mild C. difficile infection or if oral administration won’t work for the patient?

A

Metronidazole

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

What is the preferred tx for recurrent C. difficile infection?

A

Fidaxomicin (macrolide)

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

What are the adverse effects associated w/ Metronidazole?

A
  • Metallic taste in mouth
  • Disulfiram-like effect = vomiting if alcohol is ingested
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the MOA (3 of them) of the macrolide: fidaxomicin used in the treatment of recurrent C. difficile infections?

A
  • Prevent translocation of tRNA from A-site to P-site on bacterial ribosome = halts protein synthesis
  • Elicit conformational change in bacterial ribosome –> inhibit transpeptidation
  • Inhibit formation of the 50S ribosomal subunit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are 2 major adverse effects associated with Vancomycin?

A
  • Red-man syndrome
  • Nephrotoxicity (dose-dependent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the MOA of Vancomycin?

A

Binds D-alanyl-D-alanine terminus of cell wall precursor units, inhibits transglycolase and prevents extension and cross-linking of peptidoglycans = inhbits cell wall synthesis

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

What do you need to see to determine that a E. histolytica infection is pathogenic?

A

RBC’s in the cytoplasm of trophozoites (stool sample)

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

What 2 drugs can be used to eliminate invading trophozoites associted w/ E. histolytica?

A
  1. Metronidazole or
  2. Tinidazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What 2 drug choices can be used to eradicate intestinal carriage of E. histolytica?

A
  1. Paromomycin (drug of choice) or
  2. Iodoquinol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

If an individual with E. histolytica infection is an asymptomatic carrier (aka cyts or trophozoites w/ no internalized RBC’s) how are they treated?

A
  • Eradication of intestinal carriage of the organism (luminal amebicide)
  • Using either paromomycin or iodoquinol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the drug of choice for treating extraluminal E. histolytica?

Luminal amebicide of choice?

A
  • Metronidazole = extraluminal
  • Paromomycin (aminoglycoside) = luminal amebicide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What must be done when giving either metronidazole or tinidazole to treat extraluminal amebiasis associated w/ E. histolytica infection?

A

MUST be given w/ a luminal amebicide (paromomycin or iodoquinol) to ensure eradication

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

Why are Paromomycin and Iodoquinol useful for treating intraluminal E. histolytica?

Effect on extraintestinal organisms?

A
  • They are NOT absorbed in the GI
  • NO effect on extraintestinal organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which antibiotic class does paromomycin belong to?

What are unique adverse effects of this class?

A
  • Aminoglycosides
  • Nephrotoxicity and ototoxicity!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 2 steps to treatment of G. lamblia infections?

A
  1. Supportive = correct fluid and electrolyte imbalances
  2. Pharmacological = Tinidazole, Metronidazole, or Nitazoxanide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which 3 antibiotics are indicated in treating G. lamblia infections?

Distinguish the first line treatment.

A
  1. Tinidazole = first-line agent
  2. Metronidazole = not FDA approved
  3. Nitazoxanide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the MOA of Nitazoxanide?

A

Inhibition of the pyruvate-ferredoxin oxioreductase enzyme

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

Is Nitazoxanide biologically active?

A
  • No, is a prodrug
  • Converted to active metabolite, Tizoxanide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are unique adverse effects associated w/ Nitazoxanide?

A
  • Enlarged salivary glands
  • Yellow eyes
  • Dysuria
  • Bright yellow urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Oocyst w/ 4 motile sporozoites describes which protozoa?

A

Cryptosporidium parvum

22
Q

What is the treatment of choice for Cryptosporidium infection in a patient with HIV as well as someone on immunosuppressive therapy?

A

- HIV = Antiretroviral therapy + nitazoxanide (if needed)

  • Other = Reduce dose of immunosuppressant + nitazoxanide
23
Q

What is the main goal in treating Cryptosporidium infection in an immunocompromised patient?

A

Restore immune function! So they can fight the bug.

24
Q

Which 2 antibiotics can be used for Cryptosporidium infection and what is the first line agent?

A
  1. Nitazoxanide (first line)
  2. Paromomycin
25
Which nematodes are associated with intense itching at the site of penetration (i.e., in between the toes)?
- *Necator americanus* - *Ancylostoma duodenale* \*The **hookworms**
26
Which nematodes can be diagnosed based off on **eggs** in the stool?
- *Ancylostoma duodenale* - *Necator americanus* - *Ascaris lumbricoides*
27
How is the diagnosis of *Strongyloides stercoralis* made?
**LARVAE** in the stool (eggs are not passed in the stool!)
28
Which nematode must you take caution with when prescribing immunosuppressive agents, such as prednisone for asthma?
* - Strongyloides stercoralis* - Immunosuppressive agents can cause **severe autoinfection!**
29
Which 3 nematodes cause infection after ingestion of food w/ infective eggs?
- *Ascaris lumbricoides (roundworm)* - *Trichuris trichiura (whip worm)* - *Enterobius vermicularis (pinworm)*
30
What is the characteristic finding in the stool that can help with diagnosis of *Trichuris trichiura (whip worm)?*
**Eggs** in stool (**FOOTBALL shaped**)
31
What is the MOA of the agents for nematodes: Albendazole and Mebendazole?
Inhibit microtubule synthesis, **paralyze worms**, worms passed in stool
32
Which agents used for treatment of nematodes exist as a prodrug with an active metabolite only produced by first pass effect?
- Albendazole - Mebendazole
33
Why is Thiabendazole not used anymore for nematodes?
**Much more** **toxic effects** than albendazole and mebendazole
34
What is the MOA of the agent for nematodes: Ivermectin?
**Intesifies** GABA-mediated transmission of signals in peripheral nerves of the nematodes = paralysis
35
Which drug-drug interaction must be accounted for when prescribing Ivermectin for a nematode infection?
Do **NOT** combine w/ other GABA-enhancers (i.e., barbiturates, benzodiazepines, valproic acid)
36
What is the MOA of the agent for nematodes: Pyrantel pamoate?
**Neuromuscular blocking agent**, causes release of ACh and inhibits AChE = paralysis and expulsion of nematode
37
What is the drug of choice for *N. americanus* and *A. duodenale?* Alternatives?
- Albendazole (**primary**) - Mebendazole or Pyrantel Pamoate = **alternatives**
38
What are the primary treatments for *A. lumbricoides?* Alternative?
- Albendazole and Mebendazole = **primary** - Ivermectin = **alternative**
39
What is the primary treatment for *S. stercoralis?* Alternative?
- Ivermectin = **primary** - Albendazole = **alternative**
40
What is the primary treatment for *T. trichiura?* Alternative?
- Mebendazole = **primary** - Albendazole = **alternative** - Ivermectin = **2nd alternative**
41
What is the primary treatment for *E. vermicularis?*
- Albendazole - Mebendazole - Pyrantel pamoate \*ALL primary treatments!
42
What are the clinical manifestations immediately, weeks, and years later following Schistosoma spp. infection?
- **Immediate** = dermatitis - **4-8 weeks** = Katayama fever --\> hepatosplenomegaly, bronchospasm - **Years** = chronic fibrosis
43
What is the drug of choice for Schistosoma infections?
Praziquantel \*Say it in **japanese accent!**
44
What is the MOA of Praziquantel?
**Increases permeability** of the nematode and cestode cell membrane to **Ca2+ ---\> paralysis and death!**
45
What are the immediate adverse effects and after several days of Praziquantel?
- **Immediate** = headache, dizziness, drowsiness and lethargy - **Several days** = low-grade fever, pruritus, skin rash (effects of dying parasite)
46
Which parasites can be diagnosed via proglottids in stool?
- *T. solium* - *T. saginata* - *D. latum*
47
What is special about the life cycle of *Echinococcus granulosus?* Ingested how and what happens in humans?
- Humans ingest **eggs** from dog feces - Eggs hatch in the intestine and larva form **hydatid cysts!**
48
What are the 3 drugs of choice for Cestodes (i.e., *T. solium/saginata, D. latum, and E. granulosus)?*
- Praziquantel = **first-line** - Albendazole = **good choise** - Niclosamide (not effective against hydatid cysts) = **alternative tx** for tape worms
49
Niclosamide is not effective against which cestode?
- *Echinococcus granulosus* - **Not effective** against hydatid cysts
50
What is the MOA for Niclosamide? Why is its use as a therapy limited?
- Uncouples OxPhos, blocking uptake of glucose - Use limited by **side effects**, **long duration**, and **limited availability**

GI II Exam 2 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions