The cramps can be caused by a couple of things: dystonia from the Parkinson's, a magnesium deficiency, doing too much or too little exercise.

I asked this same question here. Someone suggested a very inexpensive OTC medication simply called “Leg Cramps”. It’s sold at Walmart. It worked like a charm for me.

The muscle pain can be excruciating; if/when it moves into the bones it gets far worse, and that’s when you may need meds, and it’s better if you get it under control before then if possible.
I take action before then. As soon as I feel uncomfortable I take extra strength Tylenol and do some easy stretches and get into a comfortable position to relax. Sometimes it works. If not my next step is either ice packs or heating pad and put them where they are needed most. Ice numbs my back where it hurts most, and it also relieves itching on my back. Only when I have tried all and still can’t lay still or hear the soothing music I always play. Then I head for anything I have which will add another layer to what I have done, which my include the following; screaming, throwing things, calling my primary names for not giving me something to help, cursing the wine companies for not making wine which can be consumed with my meds….well, you can see my patience is limited. 😜
Teresa3

My husband has been getting that every morning its horrible