Most newly treated hypothyroid patients see these adjustment symptoms resolve after a few weeks on their thyroid medication. Many patients require one or more dose increases following an initial starting dose to elevate their thyroid hormone levels to a proper level. This process can take several months before an adequate or optimal treatment level is achieved.
How Doctors Monitor Treatment
A new dose is monitored via follow up blood retests and if it is found to be lower than is needed to adequately treat a patient’s hypothyroidism, it is increased. In some cases a dose increase may be needed several times to reach the desired level and in some cases a dose decrease may be needed if levels test too high at some point.
If it is several months between a scheduled blood retest and a patient is experiencing symptoms that indicate the need for a dose adjustment, the treating doctor may retest the levels earlier than scheduled and adjust the patient’s dose accordingly.
If a patient’s dose is too low, they may experience one or more of the following hypothyroid symptoms:
- constipation
- depression
- fatigue
- excessive need for sleep
- dry skin
- joint and muscle aches
If a patient’s dose is too high, they may experience hyperthyroid symptoms that include the following:
- rapid heart rate
- diarrhea
- anxiety and nervousness
- sweating
- tremors
- insomnia
- muscle weakness
Types of Thyroid Hormone Doses
Adjustment symptoms may occur more often in patients who take replacement hormone brands that contain the T3 thyroid hormone (it is at least five times more potent that T4); however, patients who take a T4-only hormone may also experience dose-adjustment type symptoms. It takes about eight weeks to see a dose level-out in the body and to start doing its job properly.
The following are types of thyroid hormone medications that are administered to hypothyroid patients and that require adjustment to them in the body.
- synthetic T4
- synthetic T3
- combination synthetic T4 and T3
- combination natural (animal derived) T4 and T3
- compounded (varied ratio) mix of T4 and T3
How the Thyroid Gland Responds
Many patients, who do experience adjustment type symptoms to thyroid hormone replacement, will either see worsening hypothyroid symptoms or may have some mild to moderate hyperthyroid type symptoms. Either type usually resolves after a few weeks. This happens because the thyroid gland responds to hormone coming into the body from the outside, by shutting off part or all of its own production of hormone. When this happens, the body sometimes reaches a break-even point before improvement of hypothyroid symptoms begins.
Other patient's thyroid glands are slower to cut back production of hormone, as the dose comes into the body, so will feel hyperthyroid type symptoms for a while. These two scenarios depend on how much damage has occurred in the thyroid gland from antibody-destruction, meaning the attack from auto-antibodies being sent to the gland from the immune system (thyroid autoimmunity).
If a patient's thyroid gland has been damaged from highly elevated antibody levels, as a dose of thyroid hormone is administered, their own gland starts shutting down (atrophy) and adjustment symptoms may occur in the body. This might also be referred to as "side effects" from the starting dose.
Suppressing the TSH Level
According to the U.S. NIH (National Institutes of Health) a hormone replacement dose for hypothyroidism needs to suppress the blood TSH level (pituitary hormone that reflects thyroid levels) down to between 0.5 and 3.0 mIU/L over time (average TSH range: 0.5 to 5.0 mIU/L) and the T4 and T3 need to be around mid-range or upper-normal (ranges vary among testing labs).
This can take time and possibly several dose adjustments monitored at eight-week intervals by blood retests of TSH, T4 & T3. Most doctors prefer to start patients on a low dose and increase it upward (titrate) until it reaches the proper level to sufficiently treat a patient's hypothyroidism.
Sources:
TSH: MedlinePlus Medical Encyclopedia - U.S. NIH
Treating Hypothyroidism - endocrineweb.com
Jim Lowrance - James M. (Jim) Lowrance has authored over 100 book and ebook publications since year 2004.
