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.

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