It was not bad. The evening of the infusion I started feeling achy, I took some Advil and slept okay. Next day I was uncomfortable achy all over. If I had taken Reclast when I was working (retired now) I would have gone to work if it were an office day but then would not have functioned 100%. It was not as bad as having COVID or the flu. I took Advil the entire day, and still felt achy, but not real pain. I think in all it lasted 30 hours. I have had no other side effects since then.
I did drink 2 full glasses of water before I went for the infusion. And I took a Tylenol, as suggested by some medical sites - I got very little direction from my provider.
I should be getting another infusion this May. The cancer rheumatologist says I may then get one every other year if my numbers continue to be good. I see a local endocrinologist that orders the infusion because the rheumatologist is at the cancer center 3 1/2 hrs away. My insurance pays for all of this, with co-pays.