May 14 (HealthDay News) -- The U.S. Food and Drug Administration has approved Cimzia (certolizumab pegol) to treat moderate-to-severe rheumatoid arthritis, Belgian drug maker UCB said Thursday in a news release.

The injected drug was approved in April 2008 to treat the inflammatory bowel disorder Crohn's disease.

Rheumatoid arthritis causes pain, swelling, stiffness and loss of function in the joints, the U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases says. It can affect any joint, but is most common in the wrist and fingers.

Cimzia can have side effects including headache, upper respiratory infection, abdominal pain, nausea and injection site reactions.