I am on sust @ 500/week for 6 weeks now, and my knees are killing me. I have tried advil (up to 1200mg/day), tylenol, tylenol3, darvon, and vioxx. Vioxx is the only one that really helps. Is it normal for joint pain like this on sust? I am prone to pain in my knees naturally, but this is almost unbearable.