Fluoroquinolones are structurally similar synthetic antibiotics.They are primarily administered to treat UTIs, upper respiratory tract infections, pneumonia, and gonorrhea and include:
After oral administration, fluoroquinolones are absorbed well.
Fluoroquinolones aren’t highly protein-bound, are minimally me-tabolized in the liver, and are excreted primarily in urine.
Fluoroquinolones interrupt deoxyribonucleic acid (DNA) synthe-sis during bacterial replication by inhibiting DNA gyrase, an essen-tial enzyme of replicating DNA. As a result, the bacteria can’t re-produce.
Fluoroquinolones can be used to treat many UTIs. Each drug in this class also has specific indications.
§ Ciprofloxacin is used to treat lower respiratory tract infections, infectious diarrhea, and skin, bone, and joint infections.
§ Levofloxacin is indicated for the treatment of lower respiratory tract infections, skin infections, and UTIs.
§ Moxifloxacin is used to treat acute bacterial sinusitis and mild to moderate community-acquired pneumonia.
§ Norfloxacin is used to treat UTIs and prostatitis.
§ Ofloxacin is used to treat selected sexually transmitted dis-eases, lower respiratory tract infections, skin and skin-structure infections, and prostatitis (inflammation of the prostate gland).
Several drug interactions may occur with the fluoroquinolones.
§ Administration with antacids that contain magnesium or alu-minum hydroxide results in decreased absorption of the fluoro-quinolone.
§ Some fluoroquinolones, such as ciprofloxacin, norfloxacin, and ofloxacin, interact with xanthine derivatives, such as amino-phylline and theophylline, increasing the plasma theophylline lev-el and the risk of theophylline toxicity.
§ Giving ciprofloxacin or norfloxacin with probenecid results in decreased kidney elimination of these fluoroquinolones, increas-ing their serum levels and half-life.
§ Drugs that prolong the QT interval, such as antiarrhythmics, should be used cautiously during moxifloxacin therapy. (See Ad-verse reactions to fluoroquinolones.)