It's a chemo drug. Personally, I wouldn't go near it. But that's just me.
I've learned that these Neuro's don't know any more about these drugs than we do. It's a crap shoot if it works for you. But, you have to try it to see. That's the scary part.
Have you considered LDN? It's the least scary drug out there, in my opinion, with next to no side effects and it's so inexpensive. I cannot figure out why the medical community cannot accept that this drug works for MS for the majority of people that try it. It's almost like they refuse to believe that something so easy will work.

If it doesn't help then you can just stop taking it......with no weaning off or no unpleasant side effects.
Good luck with whatever you decide to try, Barb.