Drug safety officials are calling for an urgent safety warning for Cipro and similar antibiotics.

The Food and Drug Administration is ordering the "black box" wording due to evidence the drugs may lead to tendon ruptures. They say the ruptures could result in serious injury that can leave patients incapacitated and in need of extensive surgery.

The makers of the potent class of antibacterials will also need to develop new literature for patients to emphasize the risks. The two leading drugs covered by the warning are Cipro, made by Bayer, and Levaquin, which is made by Ortho-McNeil.

Tendon ruptures normally result from sports injuries. The link to treatment with the antibiotics is highly unusual, and scientists still don't fully understand why it happens.

FDA officials said they had received several hundred reports of tendon ruptures. However, FDA officials say many of the serious injuries could be preventable if patients stop taking the drug at the first sign of pain or swelling in a tendon, call a doctor, and switch to another antibiotic.