WHITEHOUSE STATION, N.J. -(Dow Jones)- Merck & Co .'s (MRK) Arcoxia received approval in the U.K. as a once-daily medicine for the treatment of osteoarthritis and rheumatoid arthritis.

Aroxia also relieves chronic musculo-skeletal pain, including chronic low back pain. It also treats acute pain associated with dental surgery and primary dysmenorrhea, or painful menstruation.

In a press release Monday, Merck said the U.K. is the first country in the European Union to grant medical approval to Arcoxia. Arcoxia currently is approved for similar indications in Mexico , Brazil and Peru .

(This story was originally published by Dow Jones Newswires)

In the U.S. , Merck has withdrawn its original application for Arcoxia and plans to submit an expanded New Drug Application to the Food and Drug Administration .

The new application will include new efficacy data to support an indication for ankylosing spondylitis - a disease that affects joints in the spine.

The company believes this indication will better position the product to compete successfully in the coxib class in the U.S. , where there already are three entrants: its own Vioxx and two drugs co -produced by Pharmacia Corp. (PHA) and Pfizer Inc. (PFE), Celebrex and Bextra.