Me too! I went to see my GP last week as I could not bear the pain of the 'tendon cramps' any more - I would be struck in the night and my feet and toes too seemed to find strange angles. i just did not know where to put myself - I then was frightened to sleep, as it did seem to come on more than once a night..I could also almost guarantee that any walking exercise would cause this. I explained that it was different to muscle cramp, which although unpleasant, I could cope with, and whilst the GP is unsure as to whether it is a side effect of any of my tablets, I have now had blood tests as she believes it could be a Magnesium deficiency. I take Metformin SR, gliclazide, Simvastatin, and Arimidex. She prescribed Quinine sulphate tablets, and 'touch wood' I have had realatively better night. I have woken with a small twinge, but it has not progressed as before. Quinine leaves a disgusting taste in the mouth in the morning, but that's a small niggle, compared to the awful pain before. I am now awaiting the results, so we will see..