Antibiotics can harm tendons, FDA warns

By Susan Heavey

WASHINGTON (Reuters) - Certain antibiotic drugs such as Bayer AG's Cipro need stronger "black box" warnings about the risk of tendonitis and ruptured tendons, U.S. health regulators said on Tuesday.

The warnings also would apply to Bayer's Avelox, Oscient Pharmaceuticals Corp's Factive and Depomed Inc's Proquin XR.

They would also affect Johnson & Johnson's Levaquin and Floxin and Merck & Co Inc's Noroxin. The drugs are members of a family known as fluoroquinolones.

Cipro is sold by various generic makers as ciprofloxacin and Floxin is sold generically as ofloxacin.

Labels for the antibiotics already include cautions about the tendon problems. Despite those warnings, "the FDA continues to receive a considerable number of reports of tendon-related adverse events," Edward Cox, director of the agency's antimicrobial products office, told reporters.

"The FDA believes that these new labeling changes will better inform health-care providers and patients about the risk," Cox said.

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

Patients with tendon pain should immediately stop taking the drug, halt any exercise and call a doctor, the FDA said.

The estimated risk of tendon ruptures is about three to four times higher with fluoroquinolones, said Dr. Renata Albrecht, head of the FDA's division of special pathogen and transplant products. The rate in the general population is about 1 in 100,000, Albrecht said.

Most cases involve the Achilles tendon, which attaches the calf muscle to the heel. Less frequent ruptures affected tendons in the shoulders, biceps, hands and elsewhere.

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.

The FDA was sued earlier this year by consumer group Public Citizen, which had petitioned for the boxed warnings in 2006.

At the time, the group said government data showed 262 reported tendon ruptures, 258 cases of tendonitis and 274 other tendon disorders through the end of 2005. Since then, roughly 100 more cases have been reported, Sidney Wolfe, head of Public Citizen's Health Research Group, told Reuters on Tuesday.

The FDA's Albrecht said several hundred cases of tendon- related problems had been reported.

Public Citizen, which was calling for tendon warnings as far back as 1996, also sued the FDA to require companies to notify doctors directly about the risk, something the FDA did not order on Tuesday.