I have recently started suffering from quite bad cramp attacks, say over the last 18 months or so. I am now on Simvastatin for Cholesterol reduction and more recently on a Seretiide inhaler for Asthma control. Both these I think have increased the frequency and strength of my cramps which are now very painful. The cramps occur mainly in bed but the other day I was riding my cycle (to the Doctors) and my left leg completely froze with painful cramp. I wobbled to the curb and rested but it was a couple of minutes before I could straighten my leg and continue....this was quite scary! My Doctor suggested 'Tonic water' which she later refured to as 'Sparkling water'. I have been taking Tonic Water for a few days now, just two small glasses a day, and it does seem to be improving the situation.
Will see how it goes.... 
Crampon.
I get leg cramps bad for a few days then it eases for a few weeks then comes back. If you act fast you can ease the cramp before it gets locked in your leg. You need to straighten the leg out hard infront of you.. as soon as you feel the cramp begin. Lock your knee and raise the front of your foot with your leg muscles as if you are going to touch your shin with your toes (obviously not possible).... but the effort pulls hard on the back of your leg..painfull at first. but it can stop calf and thighs from knotting bad.
It works for me most times.
Thanks for the info. I suffer from feet and toe cramps, especially when I move while sleeping. I usually have to quickly get out of bed and walk. Happens almost every night and isn't helping me to get a restful nights sleep. I will try the tonic water (ugh) or sparkling water.
Medication for high cholesterol caused me such painful thigh cramps I had to stop taking them. I tried every pill made for the problem and all of them caused thigh cramps. Doctors know this...................
I frequantly get leg cramps and would guzzle back a can of tonic water to help relieve them while walking it off. I then looked up info on quinine and it said that a prescription for quinine usually contains 200-300 mg. A Litre of tonic water contains 83 mg of quinine so you would have to drink at least 10-8 oz glasses to get the same effect. Kind of burst my bubble.