I was diagnosed with hypothyroidism 16 years ago and over the years my dose of Levothyroxine has increased to 225mcg daily with the support of a consultant. 4 years ago I was prescribed 50mg of Sertraline by my GP to try and control menopausal night sweats the result of coming off HRT. I have been feeling ' hypo' again, over the last 6 months and looking at my blood test results the latest in November my T4 has now reduced to 17.5 lower than the level the consultant was happy for me to function at. I function at a high level T4. The T4 has been reducing over the time I've been taking the Sertaline, could this drug be causing this? Advice please as I am once again having a battle with the GP practice who will not increase my thyroxine and appear to have no other suggestions.