1)  Most people with an underactive thyroid will need lifelong therapy.

2) For best absorption, thyroid hormone should be taken first thing in the morning on empty stomach (mineral water is allowed), 1 hour before breakfast and before any other medications. Compared to water, coffee reduces absorption of levothyroxine by about 30 percent. However, if you cannot take it this way, take it every day with food, consistently. If you have changed from taking it on an empty stomach, then around six to eight weeks after you start taking it with food, you should have another TSH test to ensure you are receiving the proper amount of thyroid hormone. Don't take it some days with food, some days without, or you are sure to have erratic absorption, and it will be harder to regulate your TSH levels.

3) In patients with persistently elevated TSH despite an apparently adequate replacement dose of thyroid hormone, poor medication compliance, malabsorption or the presence of drug interactions should be checked.    

Gastrointestinal malabsorption: absorption of levothyroxine can be impaired by malabsorptive disorders such as celiac disease, inflammatory bowel disease (Crohn's disease, ulcerative colitis…), irritable bowel syndrome (IBS) - commonly associated with fibromyalgia - lactose intolerance.
The list of drugs affecting thyroid function is long, with new drugs being added. Drugs may influence thyroid homeostasis at four different levels (Click Here). They may:

Alter the synthesis and/or secretion of thyroid hormone;
Change the serum concentrations of carrier-proteins of the thyroid hormones or inhibit their binding sites to those proteins or reduce conversion of T4 to the active hormone T3, resulting in less thyroid hormone available for the target tissues;
Modify cellular uptake and metabolism of thyroid hormone;
Interfere with hormone action at the target tissues. 

The possible effect of these drugs on the results of thyroid-function tests must always be considered in decisions regarding patient care. Some of them are commonly used and quiet familiar to most of you. Some of them are clinically important such as amiodarone and lithium. Although most drug-induced changes in thyroid hormone homeostasis are transient, they can produce panic and result in unnecessary treatment. Knowledge of the site of drug interaction and the physiological features of the thyroid hormone system should enable the clinician to anticipate changes that may occur in thyroid homeostasis. (Click Here)

From a practical point of view:
Should be taken at least two hours apart from taking thyroid hormone levothyroxine (Euthyrox, Synthroid, Levoxyl) or the T3 preparation, the following drugs: calcium, iron, fiber supplements, multivitamins, aluminium hydroxide anti-acids against reflux gastro-esophageal (Maalox, Gaviscon, Gelusil), bile-acid sequestrants for hypercholesterolemia (Questran), proton-pump inhibitors for dyspepsia and gastric ulcus (Omepraxole, Losec, Nexium), laxatives, Pramin against nausea, and  Guaifenesin for fibromyalgia. These drugs may impair levothyroxine and T3 preparation absorption. 

Estrogen (either as Hormone Replacement Therapy for pre-menopause or for menopause, or in Birth Control Pill) can make the thyroid hormone less active. After beginning any estrogen therapy, a woman should always have TSH and thyroid hormones levels tested to see if the estrogen is having an impact on thyroid function or might require a thyroid hormone dosage adjustment in case of hypothyroidism.

 Insulin and oral hypoglycemic drugs for diabetes (Metformin, Glucophage, Glucomin) can reduce the effectiveness of thyroid hormone.

 Injectable anticoagulants ("blood thinners") (Heparin, Clexane), or oral anticoagulants (Coumadin, Sintrom) can on occasion become stronger in the system when thyroid hormone is added.

Tricyclic antidepressants (amitriptyline: Elatrol, Elavil, Laroxyl, Tofranil, Anafranil) and levothyroxine or T3 preparations have a mutual potentiation of their effects, that is to say, levothyroxine or T3 preparations will have increased hypothyroid action, and antidepressants will have increased efficiency.

♦  Levothyroxine increases risk of coronary insufficiency by use of Ventolin spray in case of coronary heart disease.

♦ High dose of steroids (40 mg per day) may slow-down thyroid function.

  Levothyroxine may decrease action of digitalis (Digoxin).

 A Norwegian study has shown a risk of hypothyroidism if levothyroxine is taken together with ciprofloxacin (Ciflox, Uniflox), quinolone antibiotic given for urinary and respiratory infections. They should be taken at least two hours apart.

  Amiodarone (Cordarone) and lithium may themselves cause thyroid disorders.

4) Goitrogenic foods: if you suffer from hypothyroidism (and have still a thyroid gland), you should avoid eating any food that may lead to an enlarged thyroid (goiter). Goitrogenic foods are: Brussels sprouts, rutabaga, turnips, cauliflower, African cassava, millet, cabbage, kale, broccoli, soy products, peanuts, pine nuts, rapeseed oil, mustard. They all contain goitrogen substances that block the use of iodine, competing with levothyroxine. They should not be eaten raw in large amount. Cooking will minimize their goitrogenic potential.

Soy and thyroid: recent studies agree that soy leads to goitrogenic effects only in presence of iodine insufficiency. You should also know that soy may as well interfere with the absorption of thyroid synthetic hormone. It is therefore advisable to avoid taking this medication together with soy milk. The Compendium of Pharmaceuticals and Specialties (CPS) mentions that absorption of levothyroxine may be decreased by soy flour consumption, because the latter binds to the drug during its passage through the digestive tract.
Thus, competing with levothyroxine or affecting its absorption, soy could aggravate the condition of someone suffering from hypothyroidism or iodine insufficiency. However, soy does not affect negatively the thyroid gland of people in good health.

5) Do not take your thyroid treatment before having your blood tested.

6) Under treatment, in primary hypothyroidism, the ideal target for TSH is approximately between 1.0 and 1.5 mIU/L. TSH located well below without signs of hyperthyroidism is correct and does not mean the need for dose reduction. The goal of treatment is not to keep the TSH in the middle of the "standard", as one would expect from a healthy person without treatment. The adjustment of the dose of thyroid hormone is dictated by the clinical response to treatment, that is to say, the well-being of the patient and the suppression of symptoms.

7) Any change of thyroid hormone dose should not be monitored by blood tests before six to eight weeks.

8) Do not stop taking the medication or lower your dose when you feel better.

9) While you are taking thyroid replacement therapy, tell your doctor if you have any symptoms that suggest your dose is too high, such as palpitations, rapid weight loss, restlessness or shakiness, sweating, diarrhea.

10) Metabolic temperature measurement: temperatures reflect an individual's metabolic energy state. Based on a few consecutive days, the average daytime temperature of a healthy individual is 37°C (98.6 F), and it is stable. When this average over a number of days in a row is reduced but still stable (about 36.5° C - 97.8 F), it reflects a reduction of the metabolic state and suggests a subclinical or overt clinical hypothyroidism. High body temperature may point to hyperthyroidism. Low and unstable (wide variability) temperature reflects an unstable adrenal system or adrenal fatigue. Thus, on the road to health, one wants to go from low and/or unstable temperatures to 37°C (98.6 F) and stable if possible. This is the goal of an optimally managed treatment. Metabolic temperature measurement should systematically be done prior to the start of any treatment for hypothyroidism and/or adrenal fatigue, and it should be regularly monitored. (Click Here)

11) Hypothyroidism is a risk factor contributing to atherosclerosis and coronary disease due to increased LDL and cholesterol levels. Some studies, but not others, have shown a decrease in LDL cholesterol and total cholesterol levels under treatment with levothyroxine (Levoxyl, Levothroid, Synthroid, Euthyrox). This turns out more evident in the case of overt clinical hypothyroidism than in the subclinical form. Anyway, it is important to lower unfavorable lipids parameters in the long term to reduce the risk of cardiovascular disease.

12) All patients with Hashimoto's thyroiditis should have a strict gluten-free diet.

13) All patients with Hashimoto's thyroiditis (antibodies above their reference range) must be put under immune-stimulant treatment.

14) Daily exercise, diet and/or supplements are essential for a healthy functioning thyroid. Diet should include sources of vitamins and mineral, such as iodine, folic acid, omega 3 and 6 fatty acids, zinc and selenium. If diet does not provide for this, then supplement might be required. For example, a 50-100 mg vitamin B complex, a 1000 mg vitamin C, a 200- 400 mg selenium.

Vitamin D levels need to be between 50 to 70 ng/mL (in the standards: 20 to 100 ng/mL) for thyroid receptors to respond properly. Vitamin D deficiency has been associated with numerous autoimmune diseases, and specifically with autoimmune thyroid disease. Vitamin D deficiency or insufficiency may increase fibromyalgia or hypothyroidism symptoms, and strengthen the pain. Vitamin D deficiency has another little-known role. It regulates insulin secretion and balances blood sugar. Vitamin D deficiency is associated with insulin resistance. Insulin resistance and dysglycemia adversely affect thyroid physiology in several ways.

Iron also plays an important role in thyroid hormone synthesis and in the conversion of T4 to T3 (Click Here). Ferritin is a protein that stores iron and releases it in a controlled fashion. Ferritin level reflects the amount of iron stored in the body. The ranges of ferritin can vary between laboratories but are usually between 30 – 300 ng/mL for males, and 15 – 200 ng/mL for females. Ferritin levels, in women, may need to be higher than 50 to achieve proper thyroid function (optimaly between 70 – 90). It has to be noted that low ferritin by itself may indicate hypothyroidism.

15) Energy medicine such as Reiki and acupuncture are all beneficial to the thyroid.

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