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Aztreonam is what type of b-lactam?
Monobactam
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Aztreonam has how many rings?
1 ring
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Aztreonam losses what activity due to a loss of one ring?
Gram positive activity
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What makes aztreonam unique?
It only has one ring
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What B-lactam only has one ring?
Aztreonam
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What is aztreonam active against?
Aerobic gram negative bacteria
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What kind of stability does aztreonam have against b-lactamases?
Some stability but not to all
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Aztreonam is inactive against what type of B-lactamases?
AmpC b-latamases
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Carbepenems have what level potency?
Most potent b-lactams
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What has teh highest level of potency of all B-lactam drugs?
Carbapenems
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What relative level of spectrum do Carbapenems have?
Very broad
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What are the four Carbapenems availbale?
- Imipenem
- Meropenem
- Ertapenem
- Doripenem
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What group of drugs do Iripenem, Meropenem, Doripenem and Ertapenem belong to?
Carbapenems
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What other type of molecule is similar to a Carbapenem?
Penicillin
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What is the major difference between Carbapenems and Penicillins (molecularly)?
A carbon instead of a sulfur (on carbepenem)
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What is the net charge of carbepenems?
no net charge
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What three Carbapenims have similar spectrums of activity?
- Imipenem
- Doripenem
- Meropenem
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What are Imipenem, Meropenem and Doripenem all naturally active against?
- Enterobacteriaceae
- Neisseris
- H. influenzae
- Pseudomonas aeruginosa
- Acinetobacter
- Anaerobes except clostridium
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What anaerobe does Imipenem, doripenem and meropenem not have activity against?
Clostridium
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What was the first Carbepenem?
Iripenem
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What is the reason for giving cilastatin with Imipenem?
To prevent DHP-1 renal enzymes from breaking down Imepenem to a toxin
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What drug do you give with Imipenem to prevent real breakdown and toxicity?
Cilastatin
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What Carbepenum has issues with seizures due to high doses, and poor renal function?
Imipenem
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Meropenem has a similar spectrum to Imipenem, except:
- It is less active towards gram positives
- more active against some gram negatives
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Doripenem has what spectrum?
- Gram positive = similar to Imipenem
- Gram negatives = similar to meropenem
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Ertapenem hsa what special features?
- long half life
- Similar spectrum to meropenem
- BUT poor activity against pseudomonas and acinetobacter
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What Carbapenem has a long half-life and can be dosed once a day?
Imipenem
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Doripenem is more potent against what?
Gram + and Gram - than Imi or Meropenem
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What is the advantage for Ertapenem?
It can be used on an outpatient basis
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What is the safety profile for Carbapenems?
Very safe
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Carbapenems are bacteriostatic or cidal?
Bacteriocidal
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What does T>MIC mean?
- The time above the MIC
- Expressed in a percent based on the treatment time
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A lower percent for T>MIC is better or worse?
Better, meaning it has effects sooner
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What does it mean when you have a larger percent for T>MIC?
You have an antibiotic that takes longer to have an effect
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What is the relative T>MIC of Carbapenems (bacteriostatic)?
Low (20%)
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What is the T>MIC for bacteriostatic effects on average for Penicillins and Cephalosporins ?
30-40%
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Do Cephalosporins or Carbapenems have a lower T>MIC?
Carbapenems
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Why are Carbapenems more potent?
- There are only 20 molecules of PBP2 in each e.coli
- So, you need less Carbapenem to have an effect
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Which type of B-lactam drug attacks PBP2?
Carbapenems
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Carbapenems are active against what molecule?
PBP2
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