OPTIMIZING THYROID HORMONE REPLACEMENT

When I chose to have radioactive iodine treatment I was aware that it probably would result in hypothyroidism; but I believed what most doctors believed at the time, which is that hypothyroidism is easily treated by taking a pill every day.   My experience has shown that simply isn't true--at least, not for everyone.   It hasn't been true for me.

Since researchers are now debating what the correct type and dose of replacement hormone should be, in my opinion it is irresponsible for doctors to continue giving patients the idea that treating hypothyroidism is simple--especially to patients with hyperthyroidism making a treatment choice that may result in hypothyroidism. 

The information below is intended for those who are considering treatment options for Graves' Disease, and for those who are hypothyroid following treatment and hope to feel better. 

STANDARD  TREATMENT VS. DUAL HORMONE TREATMENT

TSH  "NORMAL"  RANGE

FACTORS TO CONSIDER & DISCUSS WITH YOUR PHYSICIAN

MY EXPERIENCE WITH  SINGLE AND DUAL REPLACEMENT

Standard T4 treatment vs. dual hormone (T3 plus T4) treatment:

Besides producing T4, healthy human thyroid glands produce produce other chemicals (T1, T2, T3, and Calcitonin, for example).  T3 (triiodothyronine) is believed to be the active form of thyroid hormone; but since T4 is converted into T3 in body tissues---and since it reverses the clinically obvious signs of hypothyroidism-- the medical profession has operated under the assumption for many years that T4 is the only thyroid hormone that hypothyroid patients need to receive in order to be restored to "normal".

Standard thyroid replacement hormone consists of levothyroxine sodium,  a synthetic version of the hormone thyroxine (T4), which is the hormone healthy thyroid glands produce the most of.  Common brand names of levothyroxine in the U.S. are Synthroid, Levothroid, Levoxyl, and Unithroid. 

A number of recent studies indicate that patients feel better on a replacement hormone that contains some T3 (liothyronine), as well as the standard T4 (levothyroxine) treatment--but many doctors are still resistant to prescribing dual hormone replacement for their hypothyroid patients, for several valid reasons. 

Many hypothyroid patients still have some thyroid function of their own, and are producing some T3.  Prescribing a replacement hormone containing more T3 might result in a disproportionate amount of T3 for some of these patients.

Furthermore, T4 has a relatively long half-life, and it's easy to keep blood levels of thyroid hormone even with a once-a-day pill.  T3 has a shorter half-life, and taking it once a day will result in spikes of too much hormone, followed by dips of too little.  In order to keep blood levels even, T3 (or a drug containing T3) needs to be taken in split doses 3-4 times per day--which is not practical for the average person.  Developing a reliable time-release T3 is difficult because T3 is absorbed through the stomach, rather than the intestine (which is what time-release technology is geared for).

Another problem is that too much T3 can have negative effects on bone density and heart function (especially in older people)---so T3 treatment contains risks that aren't faced during treatment with a correct dose of T4.

Finally, some doctors believe that the early benefits patients receive from the addition of T3 that appeared in the studies doesn't necessarily last with long-term treatment.  Research continues in this area in both endocrinology and psychiatry.

The current dual hormone replacement meds available in the United States are Armour Thyroid, Westhroid, Naturethroid, and Thyrolar.   Armour Thyroid, Westhroid and Naturethroid are made from desiccated (dried) pig thyroids. Desiccated thyroid was used for hypothyroidism treatment before synthetic hormone was developed.  In former days its potency and ratio of T4 to T3 varied widely, but now batches are mixed until a standard dose is achieved, and the result is a reliable potency that is in a 20%---80%  T3 to T4 ratio.

Thyrolar is a synthetic hormone, and contains T3 and T4 only, also in a 20%--80% T3 to T4 ratio.

It's also possible to supplement regular T4 treatment with T3 in the form of Cytomel, which is presently the only pure T3 drug available in the United States.   While this means taking two different kinds of pill each day, the advantage is that the amount of T3 can be individually tailored to each patient.    

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TSH "normal" range

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Factors to consider and discuss with your doctor

Keep in mind that thyroid replacement can never exactly duplicate the function of a healthy thyroid gland, which is able to micro-adjust thyroid hormone output to all the variables affecting the body's hormone requirement (such as changes in weight, sex hormone levels, & weather). 

Thyroid replacement hormone--when given in the correct form and amount for a particular person--can eliminate the symptoms of hypothyroidism and restore the body to near-normal function.  Unfortunately, many issues regarding the correct type and amount of thyroid hormone are still under study and debate among medical professionals, which means that the treatment you receive may vary a lot from one physician to another.  Therefore, if your doctor isn't willing to find out why you aren't feeling well, or isn't willing to adjust the type or amount of replacement hormone-- consider seeking a second opinion.

According to a prominent Mayo Clinic endocrinologist who spoke at the 2002 National Graves' Disease Conference in Los Angeles, someone on standard thyroid replacement hormone (levothyroxine, or T4 replacement) should have a TSH in the lower part of the "normal" range (around 1), and should have a Free T4 at the top of the "normal" range (or even slightly above normal)  in order to compensate for both the T4 and T3 the thyroid isn't producing.  

He also recommended that because of the autoimmune nature of Graves' Disease, people who have ongoing problems should be thoroughly tested for other autoimmune factors that might be causing symptoms; and that if no other causes were found, dual replacement hormone can be prescribed on a trial basis to see if it eliminates the symptoms.  He recommended that any T3 hormone be taken in split doses of at least 3-4 times per day, to keep blood levels even--since excess T3 can cause osteoporosis and atrial fibrillation, especially in older people.

It's now recognized that some people convert T4 to T3 more efficiently than others do.  If you're not feeling well on standard T4 treatment, ask  your doctor to check your Free T3 levels.  If they are below normal (or low normal),  he should be willing to add some T3.   

For further information on current issues in thyroid replacement, select this link out.

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My experience with single and dual replacement hormones

In October of 1996 I started on 0.75 mg of Synthroid.  Over the next three years my dose went up to 1.0 -- 1.12 -- 1.25 -- 1.37 -- 1.50, as my thyroid continued to die out and hypothyroid symptoms returned.  While I felt much better than I had previously, I still didn't feel "right".  My main symptoms were brain fog, difficulty controlling my weight, difficulty getting out of bed in the morning, fatigue in my forearm muscles, and a general sluggishness.  On long bike rides my performance was variable.  I wasn't really depressed; but I didn't have much ambition, and noticed I no longer really enjoyed listening to music.  My endocrinologist had adjusted my hormone until my TSH was about as low as it could be without being abnormal, and my Free T4 was actually above normal--so I believed nothing more could be done, and regretted very much that I'd had the radioactive iodine.

In 1999 the New England Journal of Medicine published a study indicating that patients felt better on thyroid replacement that substituted 12.5 micrograms of T3 for 50 micrograms of the T4 replacement hormone.  I talked to my endocrinologist about the study.  He wasn't convinced, but tested me for other conditions that could be causing my symptoms, and also tested my Free T3 levels.  He found no other abnormalities, but my Free T3 was at the lowest normal level--so he switched me to 2 grains (120 mg) of Armour Thyroid. 

In the first week or two of switching to Armour I had some occasional hyper-type symptoms, which went entirely away when I'd been on it awhile. 

Within three days there was an amazing change in the way I felt, both physically and emotionally.  I felt more like myself again, with more energy and more interest in life again.  Music became enjoyable, and I began to wake in the mornings feeling rested and ready to begin the day, without feeling the need to "sleep in".  It felt like a miracle; and though I think in time I began to take feeling better for granted, the changes have lasted almost three years now (not counting the need for two more increases in dose--to 160 and then 180 mg of Armour).

In 2002 I've felt the best I have for many years, after being on the same dose of Armour for a year and a half. 

Recently my TSH went a little too low, so my doctor and I decided to switch from Armour to Synthroid (1.37 mg and Cytomel, 15 mcg per day split into three daily doses, in order to keep the blood levels more even.  So far I'm not feeling that great, but that's always been true for me when changing doses of replacement hormone.  I go back in January of 2003, and there may need to be some fine-tuning of the dose at that time.

2003 Update:

I continued to feel significantly unwell on the particular Synthroid/Cytomel dose I was taking, even though my TSH was "normal"  and below 1.  My endocrinologist decided to return me to my previous dose of Armour, since I had felt well at those levels.  I began feeling well again very soon.

In late 2003 a new study was released by some doctors in Amsterdam giving strong evidence that some treated Graves' Disease patients who continue to have a certain kind of antibodies (TBII) -- these antibodies aren't tested in routine clinical practice -- have suppressed TSH levels independently of Free T4 and T3 levels that are well into the normal range.  

I was tested for these antibodies in a study I participated in, and did have a high level of them, over two years after treatment with radioactive iodine.  My TSH had remained totally suppressed for nearly 5 months after I had become hypothyroid and was on thyroid replacement hormone. 

Interestingly, this year my TSH temporarily normalized on the same dose of Armour that usually reflects a slightly suppressed TSH, while I was taking Prednisone for a treatment-resistant sinus infection.  I  believe this lends support to the theory that these antibodies are presently suppressing my TSH to some degree.  Every time my Free T4 and Free T3 are tested, they are both in the lower part of the normal range, even though I split my T3 into four daily doses.  My blood levels shouldn't be reflecting the lower part of a "spike and drop" situation, so I think it's reasonable to assume that my Free T4 and Free T3 really do run low-normal on the dose of thyroid replacement I'm receiving, and that my TSH is slightly suppressed because of the TBII antibodies in my system.  I hope the medical research community pays serious attention to this new information and finds a way to integrate it into clinical practice for those of us it might be affecting.

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* The information in this web site is for educational purposes only and is not providing medical or professional advice. It should not be used for diagnosing or treating a health problem or disease. It is not a substitute for professional medical care. If you have or suspect you might have any health problems, you should consult a physician.

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