Methotrexate falls into the category of medications called DMARDs (Disease modifying anti-rheumatic drugs). This is a medication that has been shown to slow down the destructive process in joints of patients with rheumatoid arthritis.
Vioxx (no longer available) is in a class of medications called NSAIDS (Nonsteroidal Antiinflammatory Drugs). Many other NSAIDS are still used in treating musculoskeletal problems (some of these are naproxen, ibuprofen, diclofenac, Celebrex, and many others). In rheumatoid arthritis these medicaions may help in relieving symptoms but are not disease modifying.
You may find more information about NSAIDS on the website: