I had 3 Reclast infusions over a 4.5 year period because of osteoporosis (DEXA bone scans). I had flu-like symptoms from the Reclast for several days, otherwise no adverse reactions. I now have early to moderate osteopenia. I have lifted weights/resistance training for decades (I'm 70), taken calcium/magnesium citrate, very healthy diet, and still osteoporosis. I bike and hike and lot, so wanted to decrease my risk of broken bones. I have a couple of friends with osteoporosis and they have had a lot of breaks; one was on vitamin B12 injections and the other Reclast pills (don't know why pills rather than infusion; her only side effect is loss of smell and taste).