I have struggled with dehydration. Not sure what protocol you’re getting. I’m on the Folfirinox regimen. The 5FU is administered through a portable pump for 46 hours. When I return to the clinic for pump removal I get an additional IV. That helped with dehydration but not enough. After my last cycle (number 8) I went back to the clinic the following day for an additional IV. That seemed to help. I’ve also switched from water/Gatorade mix to a product called Liquid IV that one of the nurses suggested. It’s available at any of the pharmacy chains. That also seems to help. Good luck.