Was taking 20mg of Carbimazole for the past 8 weeks and saw endo last Tuesday who says my T4 has now gone up again to 38.4 (12-22) and has told me to increase to 40mg. My T4 has never been back in range yet! He said I was very unfortunate and I maybe have to consider block and replace therapy instead. Over the past few days I've been feeling really shaky and very flu'y and now have to wait another 8 weeks to see endo again and don't really want to feel like this until then. Has anyone has this happen to them?