WASHINGTON, D.C. – The U.S. Food and Drug Administration (FDA) should strongly warn the public about the risk of tendon rupture associated with Cipro and other fluoroquinolone antibiotics, Public Citizen said today in a petition to the agency. The FDA should do this by requiring a “black box” warning on the drugs’ packaging and requiring pharmacists to give patients FDA-approved medication guides that also carry the warning, the group said.

Public Citizen joined with Illinois Attorney General Lisa Madigan’s office, which also sent the FDA an addendum to its earlier petition urging the agency to act. Both Public Citizen’s petition and the Illinois Attorney General’s office letter to the FDA are available at www.WorstPills.org.

“The numbers are startling. Tendon ruptures associated with these drugs continue to occur at a disturbing rate but could be prevented if doctors and patients were more aware of early warning signals, such as the onset of tendon pain, and switched to other antibiotics,” said Dr. Sidney Wolfe, director of Public Citizen’s Health Research Group. “The FDA must act and require black box warnings and patient information guides.”

Public Citizen’s review of the FDA’s adverse event database shows 262 reported cases of tendon ruptures, 258 cases of tendonitis and 274 cases of other tendon disorders between November 1997 and Dec. 31, 2005, associated with the fluoroquinolone antibiotics, with 175 of those occurring since the beginning of 2003. Sixty-one percent of the ruptures were associated with Levaquin, which has accounted for 45 percent of all fluoroquinolone prescriptions in the past four years, while 23 percent of the ruptures were associated with Cipro.

The tendon that most frequently ruptures is the Achilles tendon, which causes sudden and severe pain, swelling and bruising, and difficulty walking. Other tendon ruptures have occurred in the rotator cuff (the shoulder), the biceps, the hand and the thumb. One theory is that fluoroquinolones are toxic to tendon fibers and may decrease blood supply in tendons that already have a limited blood supply.

These antibiotics, which are widely prescribed for gastrointestinal, respiratory and genito?urinary tract infections, include Cipro (Ciprofloxacin, made by Bayer), Penetrex (Enoxacin, made by Aventis), Tequin (Gatifloxacin, made by Bristol-Myers Squibb), Levaquin (Levofloxacin, made by Ortho-McNeil), Maxaquin (Lomefloxacin, made by Unimed), Avelox (Moxifloxacin, made by Bayer), Noroxin (Norfloxacin, made by Merck) and Floxin (Ofloxacin, made by Daiichi-Sankyo).

Public Citizen’s petition follows a 1996 petition the nonprofit group filed seeking a warning on the label of fluoroquinolones. The FDA that year granted the petition, but the warning is buried in the list of possible adverse reactions and so has been inadequate.

In April 2005, the Illinois Attorney General’s office petitioned the FDA to place a black box warning on the drugs, but the FDA has never responded substantively to the petition. A black box warning is in bold type and surrounded by a black box to make it stand out.

“Consumers and physicians have a right to know the adverse effects associated with prescription medicines,” Illinois Attorney General Lisa Madigan said.  “We join with Public Citizen in urging the FDA to take prompt action on these petitions.”