Hi Bob, welcome to the community and I'm so sorry you are having these symptoms.  With any high fever, you *need* to see your Dr. to make sure there isn't something else causing this.  The patient info on Actonel doesn't mention your symptoms, but that doesn't mean that you aren't experiencing symptoms that weren't seen in the studies done on Actonel.    I hope others will respond with there experiences on Actonel, since I didn't have these problems when I took it.  Shaking, fever, weakness and weight loss should be treated, and I think it's best to contact your Dr. right away.    It really hard to say if it's the medication causing this, but in any case, you need to get medical attention.  If it's not the medication, then you most certainly would want to know what is causing this.   Good luck and keep us posted so we know how you do.  If you have any other problems or concerns just post again, but please call your Dr. to take care of this.