Pfizer Inc. said Monday the Food and Drug Administration approved and finalized prescription information of painkiller Celebrex (search) for the treatment of pain associated with ankylosing spondylitis, a form of arthritis that affects the spine.

The New York-based drug development company noted ankylosing spondylitis, which usually strikes people between the ages of 17 and 35, marks the sixth approved indication for Celebrex in the United States.

Pfizer noted that as expected, the final label for the drug contains a warning for potential cardiovascular and gastrointestinal risks.

The addition of a warning follows an FDA advisery panel recommendation that stronger warnings be added to Celebrex-type medicines, as well as to older, nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen.

Pfizer has seen Celebrex sales drop in recent months due to concerns about its effect on the heart. The drug has been linked to cardiovascular risks in studies and belongs to the same Cox-2 inhibitor (search) class as Merck & Co.'s Vioxx and Pfizer's own Bextra, which have been pulled from the market because of risks.