My wife used Sativex for a few month period when it first got approved for use in Canada back in 2004 (I think it was around that time) She was suffering from numerous leg spasms and associated pain. It did work and the spasms and pain subsided significantly. There was no side effects and despite what some people have written on the net about getting "high" on Sativex, it simply did not happen.
While the medication did work, it was quite pricey back then. I can only assume that the price has increased in the meantime.
Hope this helps.