Quinolone antibiotic
Quinolone antibiotics constitute a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone.[1] They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry, specifically poultry production.[2]
Quinolone
Nearly all quinolone antibiotics in use are fluoroquinolones, which contain a fluorine atom in their chemical structure and are effective against both Gram-negative and Gram-positive bacteria. One example is ciprofloxacin, one of the most widely used antibiotics worldwide.[3][4]
Interactions[edit]
Products containing multivalent cations, such as aluminium- or magnesium-containing antacids, and products containing calcium, iron, or zinc invariably result in marked reduction of oral absorption of fluoroquinolones.[44] Other drugs that interact with fluoroquinolones include sucralfate, probenecid, cimetidine, theophylline, warfarin, antiviral agents, phenytoin, cyclosporine, rifampin, pyrazinamide, and cycloserine.[44]
Administration of quinolone antibiotics to a benzodiazepine-dependent individual can precipitate acute benzodiazepine withdrawal symptoms due to quinolones displacing benzodiazepines from their binding sites.[45] Fluoroquinolones have varying specificity for cytochrome P450, so may have interactions with drugs cleared by those enzymes; the order from most P450-inhibitory to least, is enoxacin > ciprofloxacin > norfloxacin > ofloxacin, levofloxacin, trovafloxacin, gatifloxacin, moxifloxacin.[44]
Contraindications[edit]
Quinolones are not recommended in people with epilepsy, Marfan's syndrome, Ehlers-Danlos Syndrome,[46] QT prolongation, pre-existing CNS lesions, or CNS inflammation, or who have had a stroke.[31] They are best avoided in the athlete population.[47] Safety concerns exist for fluoroquinolone use during pregnancy, so they are contraindicated unless no other safe alternative antibiotic exists.[48] However, one meta-analysis looking at the outcome of pregnancies involving quinolone use in the first trimester found no increased risk of malformations.[49] They are also contraindicated in children due to the risks of damage to the musculoskeletal system.[50] Their use in children is not absolutely contraindicated, however. For certain severe infections where other antibiotics are not an option, their use can be justified.[51] Quinolones should also not be given to people with a known hypersensitivity to the drug class.[52][53]
The basic pharmacophore, or active structure, of the fluoroquinolone class is based upon the quinoline ring system.[54] The addition of the fluorine atom at C6 distinguishes the successive-generation fluoroquinolones from the first-generation of quinolones. The addition of the C6 fluorine atom has since been demonstrated not to be required for the antibacterial activity of this class (circa 1997).[55]