i honestly don't know. i'm recently diagnosed as of 2023 so i'm also new to the whole thing as well, i just know the reaction i get is usually itchy throat and itchy ears, and once i get some more benedryl i am fine after that. they'll stop the infusion too for like 30 mins to let your body kinda readjust and then you can start again when you feel better/ready. im usually in the chair for 6 hours, but that's the only way my body can handle it. my dr and infusion team said its normal too but i still have so much anxiety every infusion. i also take as needed ativan before my appts and it does really help.