Leg cramps

I have high blood pressure so I take mavik to help regulate it which increases my potassium levels. I drink lots of water and I still find I'm getting leg cramps really bad somedays. When it happens in one leg I start to stretch but the other leg cramps up so now I'm on pain on the floor massaging them till it subsides. Anyone have a solution how to stop this from happening or at least less often? Happens all the time