Thanks folks---for all the info. That's much more than I asked for--and it is appreciated.
Another question: Is Ritalin related to these drugs? --- The extreme effects of fatigue and heat on us people with MS prompted my neurologist to prescribe Ritalin for me twice a day----20 mg. It seems to be a regulated drug. Possibly addictive. But it works -- I am much more focused. Even may lose some weight---a GOOD side effect from my point of view. Wears of very quickly and doesn't get in the way of nightly sleep at all.