Hello, In the last few weeks I've gone back on amitritpyline (10mg) to help with sleep and clenching jaw. My fibromyaligia (I think) symptoms have got steadily worse - stiff achy muscles esp on waking - clicky neck and stiff shoulders arms - heaviness in muscles etc. Can amitriptyline suppress thyroid function? These are symptoms that all improved greatly when I switched from levothyroxine to ERFA thyroid (NDT) I take 60 mg ERFA thyroid in the mornings. In the past I've only taken 5mg amitriptyline but it didn't keep me asleep properly so 10mg is the most I've ever taken daily. Seeing GP tomorrow to discuss. Thoughts welcome!