Question: I had Graves’ disease 20 years ago, and subsequently became hypothyroid. I have been on the same amount of Synthroid for 15 years. But six months ago, I began feeling anxious and nervous, and started experiencing profuse sweating, and heart palpitations. I had my TSH checked and it’s fine. But can you tell me if this it is unusual for someone to be on a stable dosage of thyroid medication for so long and then become hyperthyroid?
Dr. Hibberd's answer:
You are right. Something is wrong. The symptoms you describe certainly do sound like you are being over-supplemented with thyroid hormone. But you should have your free T3 and free T4 levels checked.
It is not unusual to have to adjust thyroid medication periodically, especially when many patients are taking different generic products. Your TSH, together with your free T4 and Free T3 levels will help determine whether you have an extra source of thyroid hormone beyond your Synthroid supplementation, or whether you need to reduce your Synthroid dose.
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