I've been getting these for a little over two years for an autoimmune disease and was just diagnosed with POTS in December. I was told to drink water to avoid headaches that can come with Ivig. I usually drink 6 tall glasses of water, straight water nothing else, throughout the day starting two days before the infusion, then sip water throughout the infusion too. I then get a bag of saline after. Once I'm home I drink two more glasses of water then another one the day after. This has worked out for me so far, but I know everyone is different. If he's having side effects, slowing the infusion rate down can also help sometimes too. Since having POTS, I've had some blood pressure issues with Ivig I didn't have before. It can temporarily lower your BP as a side effect during the infusion then typically comes back up, but in my case it started dropping really low because of the beta blocker. I'm on florinef now so it's come back up and the infusions are running smoother. I also notice when I drink straight water without gatorade or tomato juice, I feel worse throughout the day, but I don't want a post infusion headache either. It's a balancing act I suppose.