Two things I have discovered will help: for immediate relief, especially cramp in the leg muscles, rub in pure essential oil of lavender. This does ease the cramp.
To prevent cramp, however, try this:
That's right, tonic water. Just one glass a day helps to prevent cramp. Apparently it is the quinine in the tonic (just 67mg/l) that does the trick.
I ran out of tonic a week or so ago, and the cramp came back.
"If you think nobody cares whether you're alive or dead, try missing a couple of payments"