Levothyroxine is a synthetic form of the thyroid hormone thyroxine (T4). It is the drug of choice to treat hypothyroidism. It is also the standard medical treatment for goitre, or an enlarged thyroid.
Levothyroxine hormone replacement therapy is only available with a doctor’s prescription. Brand names include; Eutroxsig®, Oroxine®, Synthroid® and Levothroid®. This thyroid medication can range in strength from 50 to 200 micrograms.
Levothyroxine dosage + side effects
Levothyroxine is normally first prescribed using a dose at the lower end of the dosing range. Thyroid function tests are routinely performed to check that the dose is adequate to meet individual requirements.
Dose adjustments are done gradually until the level of thyroid stimulating hormone (TSH) drops down to the lower end of the standard reference range.
Changes to the dose are minor to reduce the risk of side effects. Too much levothyroxine is associated with an increased risk of atrial fibrillation, a fast and irregular heartbeat. This is a side effect you would expect if your thyroid became overactive.
When first starting levothyroxine medication it can take three to four weeks to take effect. Once stopped, the medication will continue to have effects for one to three weeks.
The half-life of a prescribed medication is discussed in relation to how long the medication will take to clear from the body. In technical terms it refers to the time it takes for just one half of a given dose to be eliminated from the body.
The half-life of levothyroxine is six to seven days. This means it takes at least six to seven days to clear around one half of this thyroid drug from your system.
Given that levothyroxine stays in the body for a considerable length of time doctors are advised to make small adjustments to the dose at three to four week intervals.
For pregnant women or women considering having a baby their levothyroxine dose is closely monitored. The dose is often increased during pregnancy as healthy thyroid hormone activity is particularly crucial at this time. A maternal thyroid deficiency during pregnancy can impair healthy development of the baby’s brain and nervous system.
How effective is levothyroxine?
For many individuals they fail to experience improvements in their thyroid symptoms after taking leveothyroxine for months, or even years. They continue to suffer with the frustrating symptoms of a low thyroid. Looking at the role of the different thyroid hormones it becomes clearer why a single prescription of levothyroxine may be inadequate.
The thyroid normally manufactures and releases two key hormones: thyroxine (T4) and triiodothyronine (T3). While T4 does have some effects, it is considered the ‘storage’ thyroid hormone. T4 is converted to T3 by the body when a greater thyroid response is required. This means T4 needs to be converted through to T3 to be the most effective.
When conversion of T4 to the more potent T3 takes place it is usual to notice significant improvements in symptoms. T3 helps stimulate metabolism which has far reaching effects in the body. This includes sparking energy production, weight loss and firing up brain activity to improve memory and concentration.
This scenario also applies to prescribed levothyroxine; the effects are much more noticeable when the body is able to convert the supplemental T4 to T3.
It is widely assumed the body will convert levothyroxine, the synthetic form of T4, to the biologically active T3 when it needs more of this hormone. This seems to go unquestioned as a medical fact. However for many individuals this fails to occur.
Do you have a T4 to T3 conversion problem?
There are two nutrients necessary to support ongoing conversion of T4 to T3. They are zinc and selenium. Reduced conversion of T4 to T3 occurs when there is a deficiency of either of these two minerals.
Lowered conversion of T4 to T3 also occurs in response to dieting, stress, toxicity and chronic fatigue syndrome.
Many thyroid health experts advocate the use of T4/T3 medications. Using a combination of the two key hormones can compensate for the body’s reduced ability to effectively convert T4 to T3. An example of this is Armour Thyroid medication. This alternative thyroid medication contains both T4 and T3.
A Naturopathic viewpoint
From a Naturopathic viewpoint there is a broad range of factors that influence thyroid health. To see real improvements in thyroid health it is important to identify and address the underlying root causes. Stress, an unhealthy diet, specific nutrient deficiencies, chronic illness, food sensitivities and environmental toxins really take a toll on thyroid health.
A nutritional product that provides a comprehensive range of nutrients to assist healthy thyroid hormone activity is recommended. A good quality product features at the very least iodine, zinc and selenium.
Note: Leveothyroxine medication is typically advocated for life and requires ongoing monitoring. Do not discontinue or change your medication without the informed consent of your prescribing medical practitioner.
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Louise O’ Connor, the author of The Natural Thyroid Diet –The 4-Week Plan to Living Well, Living Vibrantly, who is a specialist in Thyroid Health. She is a highly regarded Australian Naturopath and founder of Wellnesswork.
The Natural Thyroid Diet goes beyond diet advice and offers practical and effective ways to achieve healthy thyroid levels within just a short period of time. For more details, Click on The-Natural-Thyroid-Diet.com