I Recently Tested 52 On A GFR Test, I Was

I recently tested 52 on a GFR test, I was 66 1 month ago, just started taking lisinopril for high blood pressure
. I have a uti can I safely take Cephalexin, a doctor gave me a prescription for this 500mg 2 times a day. I read do not take if you have kidney problems. the doctor has not discussed my results, I received them in an e-mail.