Back when I was a kid my mother used to give me quinine pills... You could buy them over the counter... And they worked... I remember one particular time I spent about 12 to 13 hours out in the alfalfa field on the second cutting of square bales and was not only sun burnt but was suffering so bad from leg cramps, I wanted to die... Quinine was the fix for the cramps... They say not to take quinine for cramps an cause it might hurt you...
10, 12 years ago I started getting leg cramps and went and I remembered the quinine and went to the Apothecary and was told that quinine was no longer for sale over the counter... Last time I tried the quinine was at a NASCAR race in Bristol, Tn. Went to a race on Sat and Sun... Sat. night went to a liquor store to buy some Schweppes Tonic with Quinine... Didn't buy any Gin, probably should have though...
Gatorade is probably the best bet...
Grampa Murked U