quinolones and fluoroquinolones Flashcards
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
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.
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.
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
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
contraindication for this drugs
pregnancy and children below 18 (inhibition of chondrogenesis)
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
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
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
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
