One thing I found better than Gatorade is V8 Calcium Enriched because it has way more potassium in it and that helped me more than anything.

Also, have them infuse it very slowly. One time when they infused it too fast, I got bad headaches. My neuro had them slow it down to between 1 and 2 hours per IV and I did far better.

My veins are also shot from too much IVSM, so I leave the hep-lock in for the whole treatment. Once they get it in, leave it no more poking. I just wrap it in gauze to hide / protect it and I use Glad Press & Seal to keep it dry in the shower.