C14

Question 1

what about Quinolones?

Answer 1

• Broad-spectrum bacterioCIDals
• Nearly all quinolones in use are fluoroquinolones (contain a fluorine)

Question 2

name Fluoroquinolones

Answer 2

1st generation (narrow spectrum ) : Nor-floxacin

2nd gen (wide spectrum ) - ciprofloxacin, Ofloxacin

3rd gen (wide spectrum) - Levo-floxacin, Moxifloxacin

Question 3

1stG Fluoroquinolone

Answer 3

Norfloxacin

*does NOT achieve adequate plasma levels for use in most systemic infections*

Question 4

Norfloxacin spectrum?

Answer 4

1st gen narrow spectrum !
the common pathogens causing UTIs

Question 5

2ndG Fluoroquinolone?

Answer 5

Ciprofloxacin and ofloxacin

Question 6

Ciprofloxacin and ofloxacin spectrum?

Answer 6

• aerobic gram negatives
• Pseudomonas
• Atypical pneumonia ( H.influenza, M.catarrhalis)
• G-‘s cocci
• Mycoplasma pneumoniae
• Chlamydophila pneumoniae

*effective in GUT, GIT, some respiratory infections
*Rapidly declining activity against gonoccocus

ofloxacin- UTI

Question 7

3rdG fluoroquinolones?

Answer 7

Respiratory fluoroquinolones

• levo.floxacin
• moxi.floxacin

Question 8

Levofloxacin & Moxifloxacin spectrum?

Answer 8

• Respiratory tract infections
• enhanced activity against gram + cocci :
  (1. S.pneumoniae
  2. Enterococci
  3. MRSA)
• activity against Atypicals (chlamydia, mycoplasma)
• less active against G-‘s (than 2nd gen)

Question 9

broadest spectrum fluoroquinolones?

Answer 9

moxifloxacin

• enhanced activity against anaerobes
• NOT recommended for UTIs

Question 10

fluoroquinolones pharmacoKinetix?

Answer 10

oral, IV
- oral bioavailability: good

• distribution: penetrate most body tissues
• Elimination: kidneys (active tubular secretion) (elimination blocked by probenecid.)

***moxifloxacin: eliminated partly by hepatic and biliary excretion***

Question 11

fluoroquinolones MOA?

Answer 11

• bactericidal
• Inhibits DNA replication via:
• in G-‘s: binding to DNA gyrase (topo 2) >inhibit bacterial DNA synthesis
• in G+’s: binding to topoisomerase IV –> inhibit with bacterial DNA synthesis
• exhibit postantibiotic effects

Question 12

what is PostAntibiotic effect?

Answer 12

bacterial growth continues to be inhibited even after the plasma concentration of the drug has fallen below the min inhibitory concentration of the bacterium

Question 13

Resistance against fluoroquinolones?

Answer 13

• Efflux pumps or changing porin structure –> decreased intracellular accumulation of the drug
• Point mutations in the ABx binding regions –> Changes in the sensitivity of the target enzymes (eg. dna gyrase)

Question 14

Fluoroquinolones Clinical use?

Answer 14

• mainly in urogenital and GITIs by G-‘s:
  (gonococci, E coli, P aeruginosa, Salmonella, shigella)
• meningococcal carrier state
• tuberculosis

Question 15

Ofloxacin clinical use?

Answer 15

UTI

• eradicates Chlamydia trachomatis
• 7d of treatment is required

Question 16

Levofloxacin clinical use?

Answer 16

RTI
enhanced activity against gram + cocci

• community-acquired pneumonia
• against atypicals :
  1. Chlamydiae
  2. Mycoplasma
  3. Legionella

Question 17

fluoroquinolones Toxicity?

Answer 17

• GI distress
• Neurotoxicity
• dizziness, headache
• prolong the QT interval (levofloxacin, moxifloxacin)
• CONTRAINDICATED: children or pregnant women (damage growing cartilage & cause arthropathy)