cramping, palpatations d/t electolyte reduction i.e. potassium. Also if your K drops down too low you can go into lethal arrythmia such as Ventricular tachicardia. this can lead to death. I dont recommend using diuretics unless under the care of a MD to monitor your lytes.
Which one were you thinking of using?
Maybe try ripped. Ithink that is what it is called. Look in nelsons sigit should be listed there.