Public Citizen has filed a federal court suit asking that the FDA be forced to act on a petition the group says has been unanswered for 16 months, seeking a black-box warning on fluoroquinolone antibiotics (e.g., Cipro, Levaquin, and others) on the risk of serious tendon injury associated with the drug's use.

Public Citizen says the FDA has failed to act on its petition despite “long-standing evidence that fluoroquinolone antibiotics can cause tendon ruptures.”

It says a black-box warning would help make doctors and patients more aware of the risk before tendons actually rupture. The petition also asked the FDA to send a warning letter to physicians and to require an FDA-approved medication guide to be dispensed with prescriptions.

“While FDA sits idly by and ignores the problem, more people will suffer serious tendon ruptures that could have been prevented,” says Public Citizen Health Research Group director Sidney Wolfe. “The current warning is buried in a long list of possible adverse reactions and is far too easy to miss.”

Public Citizen reports that from November 1997 to December 2005, the FDA received 262 reports of tendon ruptures, mainly of the Achilles tendon; 258 cases of tendonitis; and 274 cases of other tendon disorders in patients using fluoroquinolone antibiotics. An additional 74 tendon ruptures, it says, have subsequently been reported to the FDA, for a total of 336.