Levaquin (levofloxacin) is a fluoroquinolone antibiotic, manufactured by Ortho-McNeil, a subsidiary of Johnson & Johnson. Doctors prescribe Levaquin as an antibiotic to treat bacterial infections in many different parts of the body.

While patients taking Levaquin have reported a multitude of minor side-effects, common with just about all medication, the most serious side effect reported has been an increased risk of Achilles tendonitis among current and former patients. Several studies published in medical journals have listed studies where individuals have been affected by levofloxacin-induced tendonopathy and tendon rupture.

Most recently in July 2008, the FDA announced plans to require a "black box" warning on all prescriptions of Levaquin after the consumer group Public Citizen sued the FDA to require the agency to add warnings. It will caution patients of the risk of tendonitis and tendon rupture. These ruptures usually involve the Achilles tendon, but can also include ruptures of the hand, shoulder, thumbs, and biceps, according to the FDA.