I Suffer From Very Severe Leg Cramps At Night, Trying

I suffer from very severe leg cramps at night, trying magnesium (recommended by my brother who also suffers) it worked at first but not anymore....the cramps are foot, calf, and thigh and by severe, I mean extremely painful....what does one do for that? My PCP Rx'd liquid valium at one point, but this has been going on for years & to tell the truth I'm really tired of thinking I just need to " deal with it"