I've seen a lot of posts about being unable to sleep once on Carbimazole. This can be overcome. I've just started on 10mg daily of Neo mercazo, which is just another name for carbimazole in Australia. Yes, sleep was impossible the first few nights. I now take a Mega Magnesium Powder, which also contains Calcium, Vitamins C & B6 and Potassium in balance (just before I go to bed). I sleep like a log! My heartbeat has come down with Vit C ( Ascorbic Acid). Vitamin C aids the absorption of medication, & it also helps the heart. I am doing fine witout beta blockers. Hope this helps.