The commercial drinks like Gatorade only have about 30mg a serving of potassium. They are mostly sugar and salt.

So you have to raise your Sodium level for some reason? Do you have POTS or did you have a spell of hyponatremia?

If you drink lots of water, too much, you can dilute out your sodium and develop a form of hyponatremia. It would help me answer you more completely if I knew what exactly the goal is for your doctor's suggestions.

But doctors and people in general think Gatorade is good for replenishing potassium, and it is not.

One really has to read labels carefully. I saw a question here a few years ago about a product here in US that had a huge amount of potassium in it (it was not a vegetable juice either)... The FDA only allows 99mg/tablet OTC here, so I don't know how that higher dose slipped into that posters energy drink!

It is best to read all labels before drinking commercial products, therefore. And laws and regulations may be changed and people may not notice that either.