<unk> s are not recommended in people with epilepsy, Marfan's syndrome, Ehlers-Danlos Syndrome, QT prolongation, pre-existing CNS lesions, or CNS inflammation, or who have had a stroke. They are best avoided in the athlete population. Safety concerns exist for fluoroquinolone use during pregnancy, so they are contraindicated unless no other safe alternative<unk>  exists. However, one meta-analysis looking at the outcome of pregnancies involving<unk>  use in the first trimester found no increased risk of malformations. They are also contraindicated in children due to the risks of damage to the musculoskeletal system. Their use in children is not absolutely contraindicated, however. For certain severe infections where other<unk> s are not an option, their use can be justified.<unk> s should also not be given to people with a known hypersensitivity to the drug class. The basic pharmacophore, or active structure, of the fluoroquinolone class is based upon the<unk>  ring system. The addition of the fluorine atom at C6 distinguishes the successive-generation fluoroquinolones from the first-generation of<unk> s. The addition of the C6 fluorine atom has since been demonstrated not to be required for the antibacterial activity of this class (circa 1997).
Quinolone antibiotic
Polypeptide antibiotic
Beta-lactam antibiotics
Lipase inhibitors
Nonsteroidal anti-inflammatory drug
Antiviral drug
Protease inhibitor 
Antibiotic