Osteoarthritis is a joint disease that gradually wears down cartilage and bone. It is the most common joint disorder worldwide, affecting both men and women as they grow older. Symptoms include pain and stiffness of the fingers and weight-bearing joints, such as the knees, back, and hips. Patients often take medicines, such as naproxen or ibuprofen, to reduce or take away the pain. These medicines are called traditional nonsteroidal anti-inflammatory drugs (NSAIDs). Sometimes, NSAIDs cause gastrointestinal side effects, such as stomach pain, ulcers, or bleeding. More recently developed NSAIDs (called coxibs) are thought to have less frequent and less damaging side effects.