The best treatment I have found for muscle spasms is heat, either baths (can't actually get in/out one any more), hot showers, hot water bottles, heat pads, wheaties and so on. The most effective way though is to try and work out what is causing the spasms, and try to prevent them in the first place. Not easy, I know. When I was still working, mainly sat at a computer, I had bad muscle spasms across the top of my back/shoulders. It was only after an 'Access to Work' assessment that I found this was caused by the weight of my arms in my shouders as I was working at my desk. I was supplied with lower arm rests and they helped me no ens. I also drive with my left elbow resting on the arm rest and this helped as well.
When I gave up work and was able to pace myself better, that helped as well, but I am unfortunately back to muscles spasms each day cos I am currently doing too much.
Diagnosed HEDS December 1st 2005. DD1 (20) HEDS and scoliosis (now corrected by surgery), diagnosed June 2006. DD2 (18) mild HMS. Son (11) some hypermobile joints, poor muscle strength and seems to be developing scoliosis as well, woopee!