Today I had my second Tysabri infusion and it went well. The drug caused a bit of burning in the beginning due to the initial rapid push, but then calmed down with the slower drip.
The only side effect of note occurred two weeks ago, midway between my first and second infusion: an outbreak of genital herpes that had not flared up in three years. I asked the nurse to check the side effects list and sure enough, it was listed as a possible consequence of Tysabri--along with a plethora of other infections, from gingivitis to vaginitis (both of which I battle as well).
On a positive note: I also battle hypertension, but my BP went from normal (126/63) to low (103/53) during my 3 hours at the infusion center. When the nurse read off those very low digits, I said "shouldn't I be in a coma or something?" Apparently not, since she was quite pleased.
In other words, infusion therapy is a downright meditative experience!