Practical Recommendations: Thyroid Hormone Replacement Therapy

The reality of taking a medication on a daily basis is daunting, especially a medication that can be significantly influenced by external factors. This article reviews elements such as timing of your dosing, missed or forgotten does, interfering medications and adjustments in your prescribed dose.

Dosing

Thyroid hormone is poorly absorbed by the stomach, and can be further impaired by taking the medication with food or other medications. Patients are therefore generally counseled to take their thyroid medication first thing in the morning on an empty stomach. Patients are advised to not eat for an hour after taking their thyroid medication. It is also recommended that any other prescription medications, vitamins or supplements be taken separately from thyroid hormone. For patients that are unable to take the medication in the morning, we usually recommend taking their thyroid hormone at bedtime (on an empty stomach). Once-daily dosing is sufficient for patients taking levothyroxine.

Whatever dosing program you select, try to be consistent. Counsel with your endocrinologist if you wish to modify the way you are taking your medication.

Missed/Forgotten Doses

Thyroid hormone stays in your system a long time. If you miss a single dose, you are unlikely to notice immediate effects of the missed dose. If you forget to take the medication for several days, you may begin to feel symptoms of hypothyroidism once again.

In the event that you forget to take your thyroid hormone, we generally recommend that you take it as soon as you remember. If you miss a dose it is permissible to take the missed dose the next day with your regularly scheduled dose.

Interfering Medications

Iron, calcium, soy supplements, fiber supplements and some cholesterol-lowering medications may impair absorption of thyroid hormone. Other medications such as birth control pills, estrogen, testosterone, seizure medications, depression medications, and antibiotics may change your thyroid hormone requirements. It is therefore important to check with your endocrinologist if your medications change so that appropriate monitoring and adjustment of your thyroid hormone therapy can be performed.

Changing Your Dose

It is very important that you do not adjust your dose of thyroid hormone without consulting your endocrinologist first. Small changes in the amount of thyroid hormone you are taking can result in very significant changes in your thyroid hormone levels. Even a 5% change in the dose of your medication can make a big difference. If you are not feeling well on your present dose, check in with your endocrinologist for help in sorting things out.

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