Hi my mum had half her thyroid removed many years ago, last year she was put onto warfarin to begin with her warfarin level was quiet stable, but recently she has dropped to 1.4 which is too thick, and she is complaining of being tired all the time. I have told her to ask for her thyroid levels to be checked, she is very old school and believes all the doctors tell her. would a change in her thyroid make her warfarin levels more lower than it should be. She is of the opinion that her thyroid is ok on the thyroxin she takes because it always has been. Any suggestions would be appreciated.