I have been taking Snythroid for about 18 months. In the past six months, my blood pressure is uncontrolable. I have been on 7 regiments of blood pressure medicine in the past seven months. I have been to the Emergency Room twice in the last two months with tackycardia and irregular heart beat. My fingers and hand feels as though I have carpal tunnel. I started on .25 mg of Synthroid and somehow, whether it was the doctor or the pharmacy, my medication is now 25 mg. I have been to a cardiologist, had a stress test, MRI on my kidneys, holter monitor and they can't find anything wrong with my heart. I switched doctors, hopefully, she can figure out what is wrong with me.