I was taking metformin 500 mg 4x a day from my endocronolgist. Went to a new family doctor and he changed my med to glyburide-metformin 5-500 mg.(2x) One week twice my numbers went very low to 58, 64 and high to 269, 206 but then went to normal ranges. Could my Thryoid Condition, I am taking Synthroid .75 and endocronloigst is watching it and having a sonogram next month. Could this gland be causing my numbers to sky high and go down so? Was it better to have waited to change my meds until I had my thyroid test done next month. Difficult with two doctors but I mentioned to my doctor to check with my previous one