High-dose IV vitamin C can dehydrate patients and cause nausea and headaches if the solution is too concentrated. Drink plenty of water before, during, and after the infusion. Frail patients should get a pre-hydration IV fluid bolus first.
The next thing that we are concerned about when we're giving higher doses of vitamin C is it tends to be in an IV solution that is what they call hyperosmolar, a high osmolarity, which can temporarily dehydrate the person. Now, there's ways to mitigate that, but if a person's already dehydrated, they can get nauseated and headaches and things like that if they get vitamin C too rapidly or if they're not hydrated ahead of time. Most people can just drink water enough before, during, and after the vitamin C IV and they'll be fine. In some of our more frail patients, we'll actually give them hydrating fluids before just to kind of get them level, and then we'll move on to intravenous high-dose vitamin C.
