Actually, it would be helpful to know all the circumstances around the muscle spasms such as: do you have muscle spasms because of cerebral palsy, paralysis, possibly too strenuous workout, eating too much salt in the diet, calcium supplements or just a back sprain? These separate problems would be treated differently so it always helps to tell us as much information as you can share in your question.
As a simple answer, I would say that the best product to use for muscle spasms would be the cannabis salve because it is very effective in blocking the pain from the muscle spasm and it is not psychoactive, so with discretion, you can use it even when you are away from home.
drolson