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Dr. David Derry Answers Reader Questions
Brought to you by Mary Shomon, Your Thyroid Guide
Index of Q&As with Dr. David Derry

Topic: Going from Hypothyroidism to Hyperthyroidism

A Reader Writes:

My question to you is have you ever heard of some one having a hypothyroid problem probably most of my adult life if not longer,( im 46 now) only been treated for the last 5 yrs with Synthroid, then in the last yr & 1/2 or so my thyroid has gone hyperthyroid on me which I am now on tapazole now for. Have you ever come across this before?"

David Derry Responds:

Dear Patient

If the cause of your long standing hypothyroidism was Hashimoto's there is a real chance your sequence of events you described could happen. You didn't say what your dose of Synthroid was but the intention of treatment is to give you enough thyroid to not only make you feel well but also calm the inflammatory process in the thyroid. If the dose is not adequate the thyroid is not turned off and so the smoldering inflammatory process in your thyroid can still sputter on. In which case it is possible for you to become hyperthyroid. However this is not common and most times it is transitory. That is the hyperthyroidism will die off by itself.

The Tapazole is also to calm your thyroid down. You did not say if you had any symptoms of hyperthyroidism or was this a laboratory diagnosis. If you are not clinically hyperthyroid then the Tapazole may not be necessary as most thyroid glands that are over producing will burn out on their own. (1) Also the Tapazole might work easily and quickly. Eventually you will have a trial off Tapazole to see if your thyroid has settled down.

Hope this helps answer some of your questions.


1. Howard JE. Treatment of Thyrotoxicosis. JAMA 1967; 20:146-149.

About Dr. Derry:

Dr. Derry is no longer practicing medicine.

These answers are personal opinions. Please discuss any ideas you get with your physician.

Born in 1937, I am at the cutting edge of the war baby boom. With one exception the baby boomers tend to do what I do in large numbers about ten years later. The exception was that after finishing my internship at the Toronto General Hospital in 1963, as I had planned, I started a PhD in biochemistry at the Montreal Neurological Institute at McGill University in Montreal. After completing my PhD, I was hired by the Department of Pharmacology at the University of Toronto to teach and do research. Within a short time I became a Medical Research Council Scholar, which meant the Medical Research Council of Canada paid my salary to do research. Domestic rearrangements suddenly placed five children between the ages of 5 and 9 under my care. I abandoned my research career and took all five children, a new wife and dog out west to Victoria British Columbia.

My aim in 30 years of General Practice (an honor and a privilege) was to learn carefully and persistently how to listen to the patient. This is the one area of medical research that has gone almost totally un-examined. Sir William Osler, who I feel was the greatest physician of all time, said: if you listen to the patient they will usually give you the diagnosis and if you listen even more carefully they will likely indicate the best treatment for them. Gradually with the help of multiple self-development courses over the years I learned to listen by just getting my ego out of the way. From my patients I learned everything. Because of the arrival of effective treatments with potential side-effects, in 1945 the out-dated Hippocratic oath of “do no harm” was replaced with a new principle of ethical patient care namely “Consider first the well-being of the patient.” Combining extensive medical-literature reading with what I learned daily from patients clarified which approaches and treatments assured the “well-being of the patient.”

Learn More About Hypothyroidism & Hyperthyroidism Now

Read more Q&As with Dr. David Derry now

Read Living Well With Hypothyroidism
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