The side effect may not be listed until enough people complain of the issue. It is not to say that they have reported and gathered all of the side effects. Someone else mentioned this site. http://www.fda.gov/medwatch/report.htm or you can call 1-800-332-1088. You might report your increased GFR to them. Although, it would be hard to prove that it was related to a possible side effect of the medication or just an increase in water intake (which can increase GFR) also. I had my mother ask her Urologist if she should take Prolia. He was not too concerned but she is not severe CKD but a Stage 3. All drugs have SEs, just need to find one that U & your MD feel comfortable with. Best of Health to All!