I just had my first Reclast infusion. About 36 hours after the infusion I experienced some shivering and felt achey. I took some Tylenol. It started a couple of hours before bedtime and when I woke up it was gone. Hopefully that will be the end of it. I have been on Prolia for several years and it took me into normal bone density for a woman my age (63). I'm going off it for awhile and was prescribed Reclast to make the transition and avoid rebound fractures.