160 adverse events happened in 2007 from switching sources of thyroid hormone, during an Endocrine Society and American Thyroid Association reported study. The FDA method of determining that different brands of thyroid hormone are equal is seriously flawed.
Thyroid hormone therapy requires fine tuning with TSH as an endpoint. If you get switched,the other thyroid pill may be different enough to cause you harm.
The pill you were taking at the time your endocrinologist did the TSH testing should be the one you get from your drug store. If it is not, then you would need a new thyroid test in six weeks to see if this company thyroid hormone is still giving the correct amount by TSH re-testing.
This is what needs to be done, and it should not be necessary if you received the same pill your were taking when you were first tested.
However, the FDA in it's wisdom, has not allowed the black box warning to be added to the PDR listing of thyroid hormones. Elderly and thyroid cancer patients are most at risk for adverse results do to the switching of brands. The elderly have heart problems if the dose is off.
Cancer patients can have regrowth of a dormant cancer if the thyroid hormone is inadequate, or heart problems if it is excessive.
Here is my advice:
1. Until FDA changes it's methods, the patient must be his/her own best advocate.
2. Demand to receive the prescription given to you. Do not substitute prescription from your physician.
3. Insist on receiving the same company thyroid pill that you were tested on, from the drug store.
4. Look at the pill at the store to see if it is the same shape and color as the test pill, and that the store clearly informs you that it is the same as you were taking when you had the tests in your physicians office.
Dr. Guttler has been a Thyroid Expert for 31 years, board certified in endocrinology, Clinical Professor of Medicine, Keck School Medicine USC. He was the president of the Academy of Clinical Thyroidologists, www.thyroidologists.com.