34)Quinolones. Fluoroquinolones Flashcards
Quinolones
Broad spec bactericides
Have a bicyclic core structure related to 4-quinolone
- Almost all contain a Fluorine atom ⇢ known as Fluoroquinolones
- Effective against both G+ & G-ve bacteria
Classification
1st gen ⇢ Nalidixic acid + Oxalinic acid (Not used anymore)
2nd gen ⇢ Norfloxacin, Ciprofloxacin + Ofloxacin
3rd gen ⇢ Levofloxacin
4th Gen ⇢ Trovafloxacin
Pharamcodynamics
Broad spec + B-lactase resistant drugs
Bactericidal
- Inhibition of DNA replication ⇢ inhibition of type II (G-ve) + IV (G+) bacterial topoisomerases
Resistance
- Due to point mutations ⇢ E.coli has high resistance
- Change in porin structure in G-ve bacteria
Pharmacokinetics
Well absorbed
High bioavailability
Antacids ⇣ availability
⇣ binding ability to serum proteins
- Fluoroquinolones ⇢ eliminated by tubular secretion or GF
- Ciprofloxacin + Norfloxacin ⇢ partly hepatic exertion via P450 + party renal excretion
- Ofloxacin ⇢ Urine excretion
Accumulates in tissues ⇢ kidneys, prostate + lungs
All quinolones concentrated in phagocytes ⇢ fail to cross BBB
Clinical uses in dentistry
UTIS - nor + oxofoloxacin
Bacterial diarrhoea + Intrabdominal infections - norfloxacin + oxofloxacin
RT infections - cipro, oxox + moxifloxacin
STI gonococcal infections - oxo + ciprofloxacin
H. Pylori - levo, moxi + sparfloxacin
Tuberculosis - ciprofloxacin
Anthrax treatment - Ciprofloxacin
Adverse reactions
Nausea, vomiting diarrhoea + headache
Risk of tendinitis, muscle damage + nervous system involvement
Abnormal liver functions
Nephrotoxicity - crystaluria
Contraindiactions
Heart disorders
epilepsy
CNS inflammation
Kidney/heart/lung transplants
Corticosteroids
Pregnancy
< 18 years ⇢ cartilage erosion
Drug interactions
⇡ serum levels of ⇢ warfarin, caffeine + cyclosporine ⇢ inhibits their metabolism
Ciprofloxacin, ofloxacin + Enaxicin inhibit P450 enzyme in liver
Mg, Al, Ca, Fe ⇢ ⇣ oral absorption of fluoroquinolones
