Balancing Your Thyroid Stimulating Hormone (TSH)

Once a patient's thyroid gland has been removed surgically, they must take thyroid hormone in pill form to replace that which was previously produced by the thyroid gland.  In Canada, the thyroid replacement medications (levothyroxine) are also known by their brand names: Synthroid® and Eltroxin®. The chemical name is known as L-T4. The pill form of the hormone is chemically exactly the same as was previously produced by the gland itself.

There is a see-saw effect between the dose of L-T4 and the measurement (by blood test) of Thyroid Stimulating Hormone (TSH).  That is, a dose change providing more hormone decreases the TSH and a hormone dose change providing less hormone increases the TSH.  It takes about 6 weeks before a hormone dose change (if necessary) is fully reflected in a TSH blood test.

Thyroid cancer patients are usually provided with a dosage of L-T4 that is high enough to keep their TSH lower than the normal range.  This is also known as a 'suppressive dose'; meaning that the TSH is suppressed into the very low range.   A normal range of TSH, according to the American Association for Clinical Endocrinologists (AACE) is 0.3 - 3.0.  The suppressed range of TSH for thyroid cancer patients is often interpreted to be in the range of  0.04 - 0.4 (more information here).  Patients should become aware of the range of TSH that their own medical doctor has set as an optimum goal range for them.  This may vary according to the individual's risk of recurrence of thyroid cancer & number of years since diagnosis, balanced with risk of side effects.

It is important for each thyroid cancer patient to be getting the right dosage of L-T4 for at least two reasons.  A 'suppressive dose' helps to prevent a recurrence of thyroid cancer.  This is also known as 'thyroxine therapy'.  The second reason is that patients feel their best when their TSH is balanced.  Again, this varies individually. To learn the best ways to take L-T4 pills to get their maximum benefit, see information below.

Patients who are not getting enough hormone, that is their TSH is too high, may be hypothyroid.  Some patients are very sensitive to changes in their TSH and may have a number of symptoms of hypothyroidism with only a slight rise in TSH although for the most part, they are only noticed if the TSH rises significantly.  Patients are sometimes intentionally asked to become hypothyroid in order to have a test or treatment (such as a Tg blood test or RAI scan or treatment). Symptoms associated with hypothyroidism include:

Tiredness, loss of energy, weakness

Trouble sleeping, nightmares or excess sleep

Puffiness especially in the face and bloating

Loss of ability to concentrate, memory loss, absentmindedness

Weight gain

Anxiety, panic attacks, irritability, mood swings

Depression

Dry eyes, skin and hair; hair loss

Change in menstrual cycle

Joint pains and stiffness, muscle cramps

Intolerance to cold

Constipation and/or nausea

Tingling or numbness in fingers or toes

Itchiness

Ringing in ears

Slight changes in eyesight

 

Patients who are getting too much hormone, that is their TSH is too low, may be hyperthyroid. As above, some patients are very sensitive to changes in their TSH level and may feel symptoms with only a slight lowering of their TSH. Symptoms associated with hyperthyroidism include:

Tiredness, fatigue, exhaustion

Trouble sleeping, nightmares

Shakiness, nervousness, restlessness

Weight loss, increased hunger

Anxiety, panic attacks, irritability, mood swings

Increased sweating, warm moist hands

Hair loss, brittle nails

Change in menstrual cycle

Increased thirst

Itching, hives

Joint pains and stiffness, muscle cramps

Diarrhea

increased heart rate, palpitations, shortness of breath

It is important that each person works with their thyroid cancer specialist or doctor to achieve their own hormonal balance.  For some patients this may include a few dose changes (titrations) to achieve the goal range and feel their best.

 

Tips for Taking Thyroid Replacement

In Canada, the brand names for thyroid replacement pills (levothyroxine) are Synthroid® and Eltroxin®. The hormone in the medication is also known as L-T4.  Your doctor will prescribe a dose that is appropriate for you based on your metabolism and the desired degree of suppression of TSH. 

There is a see-saw effect between your dose of L-T4 and your measured TSH. That is, if your doctor lowers your dose, it will increase your TSH – and conversely taking a higher dose will lower your TSH.  It is very important to be on the correct dose. The degree to which a patient is on a suppressive dose (a high dose) of replacement hormone, is based on their risk for recurrence in balance with their risk of other side effects.

To help ensure that you get the targeted dose each day, take your L-T4 pill:

1. at the same time each day;
2. with a glass of water. Do not take it with hot drinks, especially coffee*;
3. on an empty stomach (1 hour before eating or drinking anything other than water, or 3 hours after).

Do not take your L-T4 pill with:

1. vitamins, minerals, etc. – especially not calcium and iron (allow 5 hours)
2. laxatives or high fibre

Do not allow your L-T4 to become heated.  If your pills are in an environment warm enough to melt chocolate, the dosage has been compromised.  Situations where L-T4 pills may become heated are in a steamy bathroom, in cupboard over the kitchen oven or stove, in a hot car, during vacations to warm destinations, etc.  If your pills are exposed to heat, dispose of them and get a fresh supply from the pharmacy. L-T4 pills that have been exposed to heat cannot recover by subsequently being cooled off.

* Altered intestinal absorption of L-thyroxine caused by coffee, Benvenga S, Bartolone L, Pappalardo MA, Russo A, Lapa D, Giorgianni G, Saraceno G, Trimarchi F., Thyroid. 2008 Mar;18(3):293-301, http://www.ncbi.nlm.nih.gov/pubmed/18341376  

 

When Should I Take My Hormone Replacement?

Although most patients are advised by their doctors to take their hormone first thing in the morning, two research studies by N. Bolk indicated that patients absorb the hormone more effectively if taken at bedtime, and if given a choice between morning and bedtime, find it more convenient to take at bedtime. It is important to be consistant with taking your replacement hormone -- therefore, a regular routine is recommended.

To learn more about the studies:

Effects of evening vs morning thyroxine ingestion on serum thyroid hormone profiles in hypothyroid patients, by Nienke Bolk et al. click here

Bedtime intake of levothyroxine may enhance thyroid hormone levels, by Nienke Bolk et al. click here