Fluoroquinolones

Fluoroquinolones

Fluoroquinolones are structurally similar synthetic antibiotics.They are primarily administered to treat UTIs, upper respiratory tract infections, pneumonia, and gonorrhea and include:

·                 ciprofloxacin

·                 levofloxacin

·                 moxifloxacin

·                 norfloxacin

·                 ofloxacin.

Pharmacokinetics

After oral administration, fluoroquinolones are absorbed well.

Metabolism and excretion

Fluoroquinolones aren’t highly protein-bound, are minimally me-tabolized in the liver, and are excreted primarily in urine.

Pharmacodynamics

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.

Pharmacotherapeutics

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).

Drug interactions

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.)