Therapeutics of Mid-Hindgut Infections Flashcards

1
Q

What is the use of Metronidazole and Tinidazole? what are acute and longterm adverse fx

A

Antiprotozoal and anti-obligate anaerobes (kills trophozoites, not cysts)

adverse fx
acute: nausea, diarrhea, alcohol intolerance, sleep disturbances
chronic - peripheral neuropathy, encephalopathy

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2
Q

What is the mechanism of fluoroquinolones? how is resistance mediated? Adverse Fx?

A

Ciprofloxacin, Levofloxacin
DNA gyrase inhibition (prevents transcription)

Resistance: plasmid mediated
adverse fx: long QT interval (arrhythmia), arthropathy (dont use in pts under 18)

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3
Q

What are 3 macrolides? mechanism? resistance? Metabolism/excretion? Adverse fx?

A

Erythromycin, Clarithromycin, Azithromycin (longest half life)
50s inhibitors (bacteriostatic)
resistance: plasmid mediated
Met: P-450
Excr: Excreted in bile
Adverse fx: Erythromycin can cause Cholestatic hepatitis

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4
Q

What drug group is Clindamycin in? What are adverse fx?

A

Macrolide-like

adverse fx: Impaired liver fxn, C. DIFF INFECTION

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5
Q

What is the mechanism of Vancomycin? What are adverse fx? uses?

A

Glycopeptide Abx: prevents cross-linking (bactericidal)
Uses: Abx a/w Colitis
adverse fx:
Red man syndrome - histamine release (flushing)
Ototoxicity
Renal toxicity

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6
Q

What bacteria most commonly causes Traveler’s Diarrhea? what is transmission? What are risk factors?

A
E. Coli (Montezuma revenge)
Food borne (fecal-oral): self limiting (3-7 days)
Risks:
Most significant = Travel Destination (S. America, Africa, Asia)
H2 blockers, PPI's
H. pylori
immunocompromised
age (very young, old)
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7
Q

When do you prescribe Abx for Travelers Diarrhea? What 2 Abx are they?

A

> 4 loose stools a day w/:
fever, blood/pus/mucus in stools

Fluoroquinolones (Ciprofloxacin)
Macrolides (Azithromycin, Rifaximin)

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8
Q

What is transmission and Sx of Shigella? and treatment?

A
Fecal oral
Diarrhea + Hemolytic Uremia
Tx:
rehydration
primary: Fluoroquinolone
secondary: Azithromycin
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9
Q

What is transmission of Salmonella? and treatment?

A

fecal oral
Tx:
drug resistant = Ceftriaxone
secondary: Azithromycin

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10
Q

How does Vibrio cholera cause diarrhea? what is primary and secondary therapy? what is transmission?

A
Oral-fecal - toxin mediated diarrhea
Tx:
Primary: Oral rehydration
Secondary: Macrolides (Azithromycin, Erythromycin)
then: fluoquinolones, tetracyclines
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11
Q

How does Death from bacillary diarrheas usually occur? which 2 bacteria are the most severe?

A

Dehydration + electrolyte imbalances
Salmonella typhi
Vibrio Cholera

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12
Q

Where is Giardia common? What is Tx for normal and pregnancy?

A

common in developed and under developed world
Tx: Metronidazole, Nitazoxanide, Albendazole
Pregnancy: Paromomycin

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13
Q

What is the life cycle for giardia?

A

Cyst is ingested
becomes trophozoite and multiplies in small bowel
becomes cyst and excreted in poop
*cysts can also come from COWS

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14
Q

What are Sx of Cryptosporidia? What is Tx?

A

Watery diarrhea, infxn goes away within week or two
one celled parasite burrows into intestine wall
Tx: Nitazoxanide, Parmomomycin

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15
Q

What are Sx of Cyclospora? Tx? how is it contracted?

A

Water/Explosive diarrhea, fever, muscle aches
Tx: Sulfamethoxazole, Trimethoprim

oocysts in water/food

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16
Q

What is the mechanism and adverse fx of Nitazoxanide?

A

metabolized to tizoxanide - inhibts pyruvate-ferredoxin pathway
Adverse fx: Pregnancy category B
Discolored urine, NVD (nausea,vomiting,diarrhea), Excessive urination

17
Q

What are the two main viruses that cause Enteritis? What is therapy

A

Rotavirus, Norovirus (astrovirus is least common)
therapy: rehydration + electrolytes
usually self limiting

18
Q

What are PPT factors for C. difficile infections? What is strongly contraindicated for C. diff infections?

A

Abx: Clindamycin, Amoxicillin, Cephalosporins, Fluoro, wide spectrum Abx

PPI, H2 antagonists
IBD
HIV, Age >65, Chemo, Immunosuppressants

Contra: Narcotic anti-diarrheals

19
Q

What are the 3 drugs of choice for C. Diff?

A
  1. Metronidazole
  2. Oral Vancomycin
  3. Oral Fidaxomicin
20
Q

What are characteristics of Fidaxomicin? (coverage, mechanism, use)

A

Narrow spectrum macrolide Abx
GRAM (+) aerobes & anaerobes

mech: binds/inhibits bacterial RNA polymerase
Use: C. difficile (least resistance)

21
Q

What are the two Tx for Cestode (tapeworm) infections?

A
  1. Praziquantel
  2. Niclosamide

only kill adults!

22
Q

What cestode has the highest risk of Cysticercosis (infection of muscle, brain, etc)?

A

Taenia solium

23
Q

What are characteristics of Praziquantel/Albendazole? (Use, mechanism, advere fx)

A

Use: Cestodes
Mech: increase calcium permeability (paralyzes)
Adverse fx: spontaneous abortions, NVD, drowsiness, pruritis