ellano,when I first asked my GI about taking methotrexate with Humira, he told me that new research was showing you shouldn't take the two together. My rheumy, on the other hand, said they have been using the combination for years and that she is comfortable with it. After exhausting all of our other options, my GI said I could do both together. It really helped my arthritis to add the methotrexate, but then my liver enzymes elevated and I was told I had to stop the mtx.
I too am scared of the risks associated with Tysabri (I think that's the only drug I'm scared to take) and have decided that I'm not ready for that option yet. But, if I become the way I was before the mtx again, I may decide the risk is worth it. It's really an individual decision based on how bad you feel and how much risk you are willing to take to feel better. My GI did tell me that we would probably know within a few months in the Tsyabri was going to work and, if it didn't, we would stop it then so that the risk was avoided. So, it may be something that you try and then decide if it works enough to be worth it.