Well the pain spasm in my legs have returned all on their own. The doctors informed me that constipation couldn’t have caused them anyway but they are not interested in pursuing it further. My Osteopath checked it out but because I drink 2-3 litres of water daily, take a magnesium supplement and have a good diet he is concerned it may be Herceptin related (I had herceptin on Monday, cramps started Wednesday) which is rare but a possibility. So now I wait until my next herceptin in two weeks and see whether my legs cramp again. The cramps are currently easing up. In the meantime I have to do breathing and relaxation exercises before bed to reduce lactic build up. Has anybody else had this problem with Herceptin?