Hello joelle,
I was in the Antegren trials which is Tysabri. I was one of the lucky ones who actually was receiving the Tysabri, and I never premedicated with anything. After the first 2 or 3 infusions, I was extremely tired for the day or two afterwards. I didn't begin to notice a change in my symptoms until after about the third infusion. The first thing I noticed was an increase in my energy level and then I was able to decreased my Zanaflex dose and eventually I was able to discontinue it. I was off of it after the study was opened and then went back on it for just a little while until it was taken off the market. I haven't been back on it since, but I anticipate going back on it soon. I never pre-medicated with anything, and didn't have any trouble with the drug. I've spoken with a few people at the infusion center that experienced headaches and took either ibuprofen or tylenol prior to their infusions.

I would probably hold off on taking anything like Benadryl unless your Dr. suggests taking it, as you wouldn't want to mask an anaphylactic reaction to the drug which could become worse over time.

Good luck, and let us know how it goes. I hope to be joining you someday in the near future.

All the best,
Chris