That's what I had to do as well. The nurse was absolutely fine with changing it to 45 minutes. Be sure to start hydrating well 2-3 days before, the day of the infusion, and for a couple of days after. Tylenol (I did 650 mg 2x/day) and Claritin (or equivalent, one 24 hr. tablet per day) at least the day before, day of, and day after. I did 2 days before and after, I think. The nurse also did a saline flush (???) before and after, I believe. Best of luck! I will be thinking good thoughts for you.