Fluoroquinolones

Fluoroquinolones kill bacteria by blocking the enzymes they need to copy their DNA. Ciprofloxacin and levofloxacin treat urinary tract, respiratory, and gastrointestinal infections. They carry boxed warnings for tendon rupture, nerve damage, and effects on the brain, so they are reserved for cases where other antibiotics are unsuitable. Antacids, calcium, and iron block their absorption, and they can prolong the QT interval.

• CiprofloxacinKnown brand names include Cipro.