1/8th to 1/4th of a tsp of table salt (or 50:50 sodium/potassium salt is my preference) in the palm of my hand works for me, which I follow with 4-8 oz of water. You can take more later if you need it. It also works with plantar fasciitis (cramps in foot arches), which I sometimes get in the middle of the night, typically after a day where I hiked a lot or let myself get dehydrated. The body seems to be screaming for both salt and water, and magnesium, which I take in pill form before bed.