quinolones and fluoroquinolones Flashcards Preview

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Flashcards in quinolones and fluoroquinolones Deck (10):
1

Mechanism of action
Cidal or cidic?


A quinolone antibiotic is any member of a large group of broad-spectrum bactericides.
Nearly all quinolone antibiotics in modern use are fluoroquinolones, which contain a fluorine atom in their chemical structure and are effective against both Gram-negative and Gram-positive bacteria.

Nucleic acid inhibitors!

Quinolones and fluoroquinolones inhibit topoisomerase II, also called DNA-gyrase+ and topoisomerase 4.

Concentration dependent bactericidal effect!
Long PAE

2

non-fluorinated quinolones
Used in?
Spectrum
ADverse effects
Contraindications!

e.g. nalidixic acid (oxolinic acid) which has low antibacterial action

Due to rapid excretion in the urine-> used mainly for lower urinary tract infections.

Narrow spectrum- gram - aerobs.

Genrally not a used drug anymore... just for UTI.

Adverse effects:
GI disturbances
CNS disturbances

Contraindications
1) Pregnancy
2) Children under 18 years
3) Quinolones allergy
4) CNS diseases.

3

flouroquinolones general
Kinetics of them (2-4 generation)

4 generation, with a common precursor: nalixdixic acid which improved antibacterial activity and broader spectrum
Better kinetics- achieving high levels in blood and tissues

High oral bioability, and impairment is by food.
CNS low penetration
Elimination mainly by renal mechanism
Dose has to be above 30 to improve bactericidal activity.




4

clinical use of 2-4 generation drugs

1) UTI
2) diarrhea, skin and soft tissue ifnfection and intraabdominal infection
3) respiratory tract infections
4) Gonococcal infection
5) Anthrax
6) Chronic or nosocomial infections

5

adverse effect of 2-4 generation:

well tolreated drugs
may damage growing cartilage (not given below age 18)
tendinitis
photosensivity
gi symtpoms
nerulogical (insominia, dizziness, headache)
cardiotoxicity- QT prolongation

6

contraindication for this drugs

pregnancy and children below 18 (inhibition of chondrogenesis)

7

First generation drug!
name
spectrum
Kinetics
Admin
Clinical use
Adverse

Norfloxacin

Spectrum: Good activity against most gram - aerobs (E.coli, K pneumonia, P mirabilis, shigella etc).

No / limited activity aganst pseudomonas, gram + cocci anerobs and more.

Kinetics:
Low bioavailability and rapid renal excretion which is why it's hard to achieve systemic concetration, but still hjigh in urinary tract

Admin: oral 2x a day

Clinical use:
UTI
enteritis

Adverse effect
GI AND CNS EFFECTS

8

2nd generation name 2 drugs
spectrum
clinical use
kinetics
Adverse

ciprofloxacin, enoxacin, olfoxacin, perflorxain, lomefloxacin

Spectrum:
1) excellent activity against gram - anerobs bacteria (ciprofloxacin is even good against Pseudo
2) B anthrax
3) Modedate / better activity against gram + cocci
4) LEgionella
5) Atpical bacteria
6) Mycobacerium

anerobs are resistant!

Clinical use:
UTI
bacterial diarrhea caused by shigella, salmonella,
Soft tissue, bone joint and systemic infections (including sepsis)
2nd option for TB

Kinetics
Oral parental and topical admin

Adverse:
GI
CNS
Bone cartilage distubances in adosclents

9

3rd generation drugs

Spectrum
Clinical use
Same adverse

Levofloxacin, sparfloxacin

Spectrum:
Similar to 2nd generation but less activity against pseudomonas
better activity against some gram + (Strep pneumona) and atypical baceria
Mycobaceria

Clinical use:
Mainly respiratory- due to the usefulness against atypical pneumonia agents (chlamydia, mycoplasma, legionella),
Prostatitis, skin infections and more.

Same shit adverse

10

4th generation

Moxifloxacin, gemifloxacin, prulifloxacin

Spectrum:
Similar to 3rd group
Further improved activity against some gram + (strep pneumoniae)
MOxifloxacin has some acitvity against anerobs aswell
INTRACEULLAR PATHOGENS!!

Clinical use:
Indications are the same as third but no UTI INDICATIONS (not efficient).
Community aquired and nosocomial RTI
Mixed infections (aerobe and anerobs) in monotherapy