What are the supposed advantages of COX 2 inhibitors like Vioxx?

Vioxx was a medicine created and marketed by Merck. Vioxx was prescribed as a medicine that could treat pain due to osteoarthritis, menstruation caused pain in women and acute pain in adults. It belonged to a class of drugs known as COX-2 inhibitors. COX-2 inhibitors were thought to be much more effective in treating pain and inflammation without the gastrointestinal side effects such as stomach ulcers and bleeding. These types of problems were thought to be much more prevalent in users of other NSAIDs such as ibuprofen and naproxen. Before it was taken off the market, Vioxx was one of the most popular anti-inflammatory drugs in the world. It is estimated that 84 million people worldwide have used the drug, including 20 million in the United States.