Tinnitus started after tablet Mitform No 8 then nausea and vomiting. I was handed the prescription and did as I was told. Stopped tablet (after 8 days} and blood sugars went back to 6.2 to 7.7 within twenty four hours. I stopped feeling nasueated and did not experience any more vomiting. Found several other people on Google were taking Metiformin had tinnitus. Felt like an insect in my ear. No side effect information is cited in my Mimms about Metiformin. Nothing on line shows Tinniuts as a side effect. But lots of real people say they had Tinnitus on this forum. I was managing on the world famous Low Glucose Index diet for years. Low Gi Australian Authors diabetes well controlled. I was diagnosed with Gluten Intolerance newly named for my indigestion condition four years ago. Till then I was treated as Iriitable Bowel Syndrome (the disease they have when they do not know what it is) for forty years. I had Pills and on one occasion saw a psychiatrist. . I was on Nexium for years and other similar tablets since the time I had hyperemesis in all pregnancies Fancy tests for gall bladder and coeliac disease nothing there. So found no reason. Until I dropped gluten four years ago, when immediate improvement meant no more medication. Recent blood tests ABa1 C sginaled the need for prescriptons (no discussion). I monitor my vital signs every day we live a long way from doctors. Spoke with 'nurse on line' her advice change doctors and prescription. I am a retired Seniof Universtiy Lectuerer in Health Sciences and Bioethics A midwife and Nurse cince 1962. Supervised Midwifery and Nursing Graduates and undergraduate following a 45 year clinical carreer. Mother of four grandother of seven. University Educator for the last 10 years of my professional life in Victoria Australia.