Hypothyroidism treatment depends on the cause. In the developed world, the commonest cause of underactive thyroid is autoimmune disease. This may be chronic and lifelong, as in Hashimoto’s thyroiditis (the most common), or transient as in viral and postpartum thyroiditis. Previous surgical removal of the thyroid and radioactive iodine treatment are less common causes. Rare causes of congenital hypothyroidism can occur where the thyroid gland is absent or its enzymes are not functioning properly.
Hypothyroidism treatment for the vast majority of sufferers in the developed world involves the use of levothyroxine – or l-thyroxine. This is the synthetic form of the thyroid hormone thryoxine or T4. The thyroid gland also produces T3 or triiodothyronine. T4 is made up of the amino acid tyrosine and four molecules of iodine, while T3 is made up of tyrosine and three molecules of iodine. T3 is the active form and is responsible for most of the metabolic effects of the thyroid hormones. T4 is a prohormone that is converted to T3 in the tissues. T4 has a longer half-life (amount of time for the hormone to be cleared) and thus once daily dosing is possible. It is for this reason that T4 is the drug of choice for hypothyroidism treatment, although some controversy exists due to recent evidence that patients feel better symptomatically on combination therapy.
Monitoring Hypothyroidism Treatment
Hypothyroidism treatment is monitored using the thyroid stimulating hormone (TSH) level. TSH is a hormone secreted by the pituitary which regulates the production of thyroid hormones by the thyroid gland. When thyroid hormone levels are low the TSH rises above normal and the opposite occurs when thyroid hormone levels are high.
The diagnosis of hypothyroidism should be certain before treatment is commenced. Unless due to transient causes, treatment is usually lifelong. Once the dose is determined it usually stays the same for the long-term. There are exceptions to this however, notably with pregnant women who should be monitored throughout pregnancy to ensure their dose is still sufficient.
Interesting Questions about Thyroid:
The thyroid is a small, butterfly-shaped gland just below the Adam’s apple. This gland plays a very important role in controlling the body’s metabolism, that is, how the body functions. It does this by producing thyroid hormones (T4 and T3), chemicals that travel through the blood to every part of the body. Thyroid hormones tell the body how fast to work and use energy.
The thyroid gland works like an air conditioner. If there are enough thyroid hormones in the blood, the gland stops making the hormones (just as an air conditioner cycles off when there is enough cool air in a house). When the body needs more thyroid hormones, the gland starts producing again.
About 20 million Americans have some form of thyroid disease. Many are undiagnosed or misdiagnosed. No age, economic group, race, or sex is immune to thyroid disease.
The thyroid gland might produce too much hormone (hyperthyroidism), making the body use energy faster than it should, or too little hormone (hypothyroidism), making the body use energy slower than it should. The gland may also become inflamed (thyroiditis) or enlarged (goiter), or develop one or more lumps (nodules).
|Fact:||Two of the most common thyroid diseases, Hashimoto’s thyroiditis and Graves’ disease, are autoimmune diseases and may run in families.|
|Fact:||Hypothyroidism is 10 times more common in women than in men.|
|Fact:||One out of five women over the age of 75 has Hashimoto’s thyroiditis, the most common cause of hypothyroidism.|
|Fact:||Thyroid dysfunction complicates 5%-9% of all pregnancies.|
|Fact:||About 15,000 new cases of thyroid cancer are reported each year.|
|Fact:||One out of every 4,000 infants is born without a working thyroid gland.|
There are several different causes of hyperthyroidism:
- The entire thyroid gland may be overactive, producing too much hormone. Doctors call this problem diffuse toxic goiter, or Graves’ disease.
- One or more lumps (also called nodules) in the gland may be overactive. One such lump is called a toxic autonomously functioning thyroid nodule, and several lumps are called a toxic multi-nodular goiter.
- The gland may be inflamed, a condition called thyroiditis. It can release the thyroid hormone that was stored in the gland, causing hyperthyroidism that lasts for a few weeks or months.
- Some patients may take more thyroid hormone pills than needed or prescribed.
- Some drugs, such as Quadrinal®, amiodarone (Cordarone®), and Lugol’s solution, contain large amounts of iodine, a chemical the thyroid uses to produce its hormones, and may cause the thyroid to produce too much hormone.
® Quadrinal is a registered trademark of Knoll Pharmaceutical.
® Cordarone is a registered trademark of Wyeth Labs.
As with any disease, it is important that you watch for the early warning signs of hypothyroidism. However, only your doctor can tell for sure whether or not you have the disease. Your doctor may examine:
Have more questions? Need more answers? Check our Full Thyroid FAQ
Standard Hypothyroidism Treatment
Hypothyroidism treatment usually starts with a dose of synthetic thyroxine of 50 – 100 µg per day. Due to the long half-life of T4 it takes about 3-4 weeks for the dose to become effective. Thus initially the blood levels should be checked every 6 – 8 weeks. Dose changes of 50 µg increments should occur until the TSH falls into the normal range. Until stabilisation of the dose the TSH should be measured at 3 and 6 months. Thereafter a yearly check is advised. In the elderly and those with cardiac disease a lower starting dose of 25 – 50 µg is preferred. Any increase of dose in this situation should be of 25 µg increments. Care should also be taken not to lower the TSH below normal. This is because too much thyroxine makes the heart work harder and can cause palpitations and even angina in those who are vulnerable.
Synthetic thyroxine is best taken on an empty stomach, as the presence of food generally interferes with absorption. A gap of 3 – 4 hours should be allowed before or after dosing before eating foods such as soy preparations, dietary fibre and iron and calcium supplements. Even the calcium in milk will reduce absorption. Medication such as antacids that contain aluminium or magnesium, cholesterol lowering medications such as cholestyramine and cholestipol, and sucralfate, a stomach ulcer medication, will reduce absorption.
During pregnancy, hypothyroidism treatment is especially important as even mild deficiency can lead to ill-effects on the developing foetus. Hypothyroid women who become pregnant can expect to increase their thyroxine dose by about 30% due to increased requirements. Serum TSH should be less than 2.5 mU/L and should be measured every 3 – 6 weeks.
For those with iodine deficiency, hypothyroidism treatment is best done with adequate iodine replacement. This occurs in South Asia, Africa and parts of Europe. Iodine can be found in saltwater fish, sea vegetables such as kelp and nori, dairy, soy milk and soy sauce and egg yolks. In inland, mountainous areas where the soil is deficient in natural iodine and seafood is hard to get, adequate dietary iodine may be difficult. The addition of iodine to table salt has overcome this problem in most of the developed world.
Hypothyroidism treatment is important and lifelong. Diagnosis should be confirmed and therapy monitored using blood tests.