Tagrisso causes cramps in my legs, feet and hands. Very painful. I keep a bottle of Magnesium oil with me at all times. Spray it on the cramp, rub it in, and the cramp is generally gone in a few seconds. Wash your hands good after using, the oil can be irritating if you touch your eyes. I also keep a bar of soap with lavender oil in my bed. I know it sounds crazy but there are many articles on the internet on users of this method. I no longer get cramps at night. For the fingernails, have your Zinc checked. I also take Biotin which helps with nails and hair.