Hi, I am 68, female, married, living in Virginia, with secondary progressive MS. I have been taking Tysabri for 3 years with my JCV + at just a little bit. I haven't had any side effects other than pain when injected and a big bruise. For the second month in a row, I have experienced lost time. I go home and I don't remember anything after leaving, including not knowing what happened during that evening. It is kinda freaky and I have mentioned to the staff, who don't seem concerned. I really would like to try something else, but neurologist says it is the best for slowing down the progression. Has anybody ever experienced anything like that or with other other medications?