WASHINGTON, July 8: Use of antibiotic drugs such as Bayer AG’s Cipro can lead to tendinitis and ruptured tendons, US health regulators said on Tuesday, calling for new strong warnings on the products.

The so-called black box warning would also apply to Bayer’s Avelox, Oscient Pharmaceuticals Corp’s Factive, Daiichi Sankyo Co Ltd’s Floxin, and Depomed Inc’s Proquin.

It would also affect Johnson & Johnson’s Levaquin and norfloxacin, which has been marketed as Noroxin by Merck & Co Inc. It was not immediately clear whether Merck still sells the product and representatives for the company had no immediate comment.After the warning, shares of Oscient fell more than 3 per cent on the Nasdaq before recovering to trade down 1.42 per cent at $1.39 in late morning trade. Shares of Bayer and Daiichi were both off less than 1 percent on the German and Tokyo exchanges. Depomed shares were up 5.4 per cent at $3.31, also on the Nasdaq.

Labels for the antibiotics already include cautions about the tendon problems, but the bolder, boxed warning would be stronger, the FDA said.

The risk is greater in patients 60 and older, those who have had certain organ transplants and those using concomitant steroid therapy, the agency said. It added doctors should restrict use of the drugs to conditions clearly caused by bacteria.—Reuters