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Fluoroquinolones
N/A
58
Microbiology
Professional
06/24/2012

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Cards

Term
What are the main QN used?
Definition
1. Ciprofloxacin (Cipro)
2. Levofloxacin (Levaquin)
3. Moxifloxacin (Avelox)
4. Gemifloxacin (Factive)
Term
When QN are combined with Beta lactams, how do you describe the efficacy of the combination?
Definition
Additive
Term
Are QN conc dependent or conc independent?
Definition
AG and QN are conc dependent
Term
QN are mostly used for what?
Definition
Double coverage!
Term
Describe the relationship between AG and QN with nephrotoxicity.
Definition
AG and QN both cause nephrotoxicity, however, QN induced nephrotoxicity is not as significant and common as AG

- QN are not very soluble and can crystalize and cause tubular necrosis
Term
What is the MOA of QN?
Definition
1. Selectively inhibit Type II Topoisomerase (DNA Gyrase and Topoisomerase IV)
Term
For gram (-) organisms, what is the primary target?
Definition
DNA Gyrase
Term
For gram (+) organisms, what is the primary target?
Definition
Topoisomerase IV
Term
What happens when you inhibit Topoisomerase IV?
Definition
Strand separation problems
Term
What happens when you inhibit DNA Gyrase?
Definition
Supercoiling problems
Term
What are we trying to do with the newer QN?
Definition
We are starting to manipulate the placement of fluoride to target DNA Gyrase or Topoisomerase IV
Term
How many generations of QN do we have?
Definition
3 generations
Term
What are the enzyme subunit and gene that codes for DNA Gyrase?
Definition
GyrA and GyrB
Term
What are the enzyme subunit and gene that codes for Topoisomerase IV?
Definition
ParC and ParE
Term
What is the oldest QN?
Definition
The oldest QN is CIPRO, then ofloxacin
Term
Cipro dominates which part of the market?
Definition
Gram neg: Enterobacter, klebsiella, ecoli
(sucks at targeting strep pneumo)
Term
Levoquin dominates which part of the market?
Definition
Gram pos (particularly CAP)
Term
What is classified as a normal QN?
Definition
Cipro
Term
What is classified as respiratory QN?
Definition
Levo, Moxi, Gemi - very selective for CAP bc these drugs are highly potent against strep pneumo which is the most common cause of CAP, COPD exacerbations, sinusitis)

Gram (+): Legionella, H. pneumoniae, Chlamydia/Mycoplasma pneumonia
Term
What is the advantage of QN?
Definition
They cover atypicals bc not all bacteria have peptidoglycan but all bacteria uses DNA Gyrase or Topoisomerase IV
Term
What is a problem of QN?
Definition
One simple mutation is all it takes for resistance
Term
What are the mechanisms of resistance for QN?
Definition
1. Chromosomal
- gyrA/B or parC/E mutations
- different QN have diff affinity for enzymes
- changes in binding affinity = increased MIC
- Gram (-) organisms seem to be more gyrA mutation prone
2. Permeability alterations
- seems to be mostly observed with gram (-) organisms
- the outer cell wall is altered or the porin expression is decreased
- QN target is in the cell and drug is unable to reach target or does so at lower than effective levels
3. Efflux
- transport QN and other antibiotics out of the cell
- associated with low to intermediate resistance
Term
How can you eliminate QN resistance?
Definition
By targeting 8-10 times above the MIC, bc these are conc dependent killing however, limited by seizures and nephrotoxicity
Term
What is a disadvantage of PO QN?
Definition
QN bind to Ca, VitD, and Mg, so the bioavailability of QN can be decrease when taken along with enteral feedings, antacids, Ensure, milk
Term
How do you decrease resistance to QN?
Definition
1. If initial MIC testing values are elevated, use max tolerated QN dose
2. Limit the use of QN in the animal population
3. Resistance can be eliminated for QN if the drug conc is 8-10x the MIC
4. Avoid interactions that decrease oral F
Term
What is the max MIC killing?
Definition
Max killing occurs at 15-20x MIC
Term
Describe the PK of QN?
Definition
1. Widely distributes to most body tissues
2. Cipro, Levo, Moxi obtain good conc in the liver, kidneys, feces, prostate, lungs, sinuses
3. Moxi is 50% metabolized by glucoronidation/sulfate conjugation, high fraction of drug eliminated via feces
4. Tissue conc > plasma
5. High intracellular concentrations
Term
What level of AUIC do you need for gram (+/-) to be effective?
Definition
Gram (+): AUIC > 30
Gram (-): AUIC > 125
Term
What level of AUIC is needed to prevent resistance for gram (+/-)?
Definition
Gram (+): AUIC > 50
Gram (-): AUIC > 100
Peak:MIC > 10:1
Term
Do QN have post-antibiotic effect?
Definition
Yes
Term
Which QN is used mostly for UTI?
Definition
Cipro and Levo - highest urine conc
(Cipro most used when SPACE is suspected)
Term
Ciprofloxacin
Definition
1. Increased Gram (-) coverage
Term
What can't Cipro be used for?
Definition
Never recommend Cipro for Pneumococcus
Term
Cipro has poor activity against what?
Definition
Cipro is poor against Enterococcus
Term
Cipro is combined with what for intra-abdominal infections?
Definition
Cipro + Flagyl
Term
Levo, Moxi, Gemi
Definition
Increased (+) coverage: S. pneumoniae, S. aureus
- Will work for MSSA, variable activity with MRSA
- E. faecalis coverage is good, E. faecium coverage is not reliable
(Amp & Gent for E. faecalis)
- Listeria coverage is good
Term
Moxifloxacin
Definition
1. Increased anaerobic coverage
2. Some use in intra-abdominal infections
3. Retains gram (+) activity
Term
Gemi and Moxi are mostly used for what?
Definition
1. CAP
2. AECB
3. DRSP CAP
Term
What is the only oral anti-pseudomonal drug?
Definition
Cipro!
Term
For serious infections, do you want to use QN?
Definition
No
Term
Will QN work for MRSA?
Definition
Not really
Term
What options do you have for drug resistant strep pneumo?
Definition
1. Gemi
2. Moxi
3. Ceftriaxone
4. Cefitaxime
5. Ceftaroline
Term
What does QN have poor to moderate activity against?
Definition
1. S. aureus
2. S. epidermidis
3. Resistance to staph develops rapidly
4. MRSA/MRSE coverage overall is rather poor
5. Moderately active in combination for Mycobacterium infections
Term
What does QN have excellent activity against?
Definition
1. Enterobacteriaceae
2. H. ducreyii
3. H. influenza
4. M. catarrhalis
5. Moxi and Gemi have increased Strep activity
6. N. gonorrhea resistance has increased
7. Covers atypicals: Chlamydia, Mycoplasma, Legionella
Term
How do you treat Pseudomonas aeruginosa UTI?
Definition
Cipro & Levo are adequate alone
Term
What is the efficacy against Pseudomonas?
What are their MIC?
Definition
Cipro > Gemi = moxi > Levo

MIC
Cipro = 4; Gemi = 4-5; Moxi = 8; Levo = 16
Term
What is the efficacy against S. pneumoniae?
Definition
Gemi > Moxi > Levo
MIC
Gemi < 0.03, Moxi <.25, Levo 1
Term
What is the efficacy of Staph aureus?
Definition
Moxi > Levo
Term
Which QN has efficacy against anearobes?
Definition
Moxifloxacin
Term
Which QN can be used for intra-abdominal infections?
Definition
Cipro and Moxi but Cipro doesnt have anaerobic cover so must be combined with flagyl
Term
Should QN be combined with AG for double coverage?
Definition
NO! No synergy or additive effects
Term
Are QN ADE tolerable?
Definition
Yes, QN are rarely d/c bc of ADR
Term
What are the ADR of QN?
Definition
1. GI
2. CNS
3. Dermatologic
4. Renal
5. Arthropathy
6. Tendonitis of Achilles, shoulder & hand
7. Chondrotoxicity
8. Vasculitis
9. Cardiotoxicity prolongation
10. Hypo/hyperglycemia
11. Teratogenicity

(Gee, CDR are ATC, VCr Have to be Tossed)
Term
What are DDI's of QN?
Definition
1. Multi-valent cation-containing products: Al, Mg, Ca, Fe, Zn
2. Sucralfate (aluminum gum)
3. Cimetidine (decreases tubular secretion of renally eliminated QN: cipro, levo)
4. Didanosine: Buffered by Al carbonate and MgOH
5. Theophylline/Caffeine (CYP1A2 interaction: Cipro)
6. Warfarin: Cipro/Levo
7. Foscarnet
8. QT prolonging medications
- Amiodarone, atypical antipsychotics, TCAs, TKIs
Term
What would you use for complicated Pseudomonal UTI?
Definition
Oral Cipro
Term
When would you use QN?
Definition
1. Drug resistant strep pneumo
2. Complicated pseudomonal UTI
3. Prostate infections
Term
What are alternative uses of QN?
Definition
1. Traveler's Diarrhea
2. Osteomyelitis
3. Otitis media
4. Bioterrorism related anthrax post exposure prophylaxis
5. Empiric therapy for severe CAP in a high risk patient or those requiring hospitalization
Term
What are some patient counseling tips?
Definition
1. Finish all medication
2. Minimize UV exposure
3. Hydrate/water
4. Bioavailability issues & arthropathy
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