I too was on Vioxx and I have never been the same since. I went to hell in a handbasket when they took it off the market :-(
Prescription motrin when given some years ago was 800mg ibuprofen 3x /day.
The problem occurs if you take that much over a long period of time. If you needed for a couple of days should not be a problem- assuming you do not have kidney/liver problems.
Just my experience that I have never had a problem taking four 200 mg at each time. Then again later in the day, more than recommended. This class of drug causes stomach upset but ibuprofen never has for me. A more specific arthritis medication are the COX-2 inhibitors that were all new oh ten years ago. These proved much more effective but a danger was uncovered in that patients had an increased likelyhood of heart problems. I was on Vioxx and for the first week I felt likely I had a new body. No more arthiritis, it was great. Vioxx was taken off the shelves last year. It helped me for longer than that but so obvious the first week. In place of that I have tried the others that were competitors to Vioxx like Celebrex and two others but they dont help me. I usually just Google a drug for this info or one site is www.Rxlist.com. I am not a doctor so see what other info you can find and average it all out. Good luck. Oh, here is a good link,...
http://arthritis.about.com/od/arthritismedications/Arthritis_Medications_Drug_Information_Drug_Side_Effects.htm