I have read that 40% experience an "acute phase reaction" with fgver and malaise with the first infusion but it tends not to happen with the next infusion.

Hydrate well (IV hydration can help), ask for an hour long infusion (vs 15 minutes). If kidney disease is present it is good to do a lower dose (more frequently).

Most people I know do fine. I am on Reclast and doing fine. Fractures from AI's effect on bones are painful and disabling in my case. I wanted to do Reclast but my doctor did not want to do it due to my other health issues.