I am now on a "management" program to keep my MG @ bay - 1 week a month for several months now.
The FIRST time I had it, I felt it IMMEDIATELY! I am not joking about that!
Now when I receive it, it tkes a few days to fully feel the effects - effects that last about 3-4 weeks.
I was told by one of the nurses that IV IG is still considered "experimental" therefore lots of neuro's do not use it. I swear by it though!
I was also told that it can be had on the kidneys - so when you have it done, make sure to drink lots and lots of water!
I get 500 mL for 5 days in a row.......much better than the mega doses that other people get!
Take care and hope this helps!