US Food and Drug Administration (FDA) Tuesday requested makers of certain antibiotics to add "black box" warnings -- strongest on FDA scale -- to a handful of drugs about the risk of tendinitis and ruptured tendons.

They are fluoroquinolone drugs including Cipro, Levaquin, Avelox, Noroxin and Floxin.

"The FDA believes that these new labeling changes will better inform health-care providers and patients about the risk," said Edward Cox, director of the agency's antimicrobial products office.

The companies that make the fluoroquinolone drugs will be required to submit label safety changes and the medication guide within 30 days of receiving the FDA notification or provide a reason why they do not believe such labeling changes are necessary, Cox said.

The fluoroquinolones drugs can increase the risk of tendonitis and tendon rupture by three to four times, according to FDA's Dr. Renata Albrecht.

The risk is greater in patients ages 60 and older, those who have had certain organ transplants and those using steroid therapy, the FDA said.

Patients should stop taking fluoroquinolone antibiotics at the first sign of tendon pain, avoid exercise and contact their doctor, the FDA said.

Normally, FDA's Dr. Renata Albrecht said, patients experience some pain or inflammation "a week or two before the patient will rupture."

Patients may recover if they act before a rupture, while others need surgery to repair a torn tendon. Even with surgery some patients may not return to normal, Albrecht said.

(Agencies via Xinhua News Agency July 9, 2008)