Tuesday, July 8, 2008 --- 10:50 a.m.

WASHINGTON (AP) -- Federal drug safety officials have imposed the government's most urgent warning on Cipro and similar antibiotics, citing risks that they can cause tendon ruptures, a serious injury that leaves some patients incapacitated.

The Food and Drug Administration on Tuesday ordered makers of flouroquinolone drugs -- a potent class of antibiotics -- to add a 'black box' warning to their products, which include Cipro, Levaquin, Floxin and other medications.

Patients should immediately stop taking the medications if they develop any tendon pain, swelling or inflammation.

(Copyright 2008 by The Associated Press. All Rights Reserved.)