Your doctor has found that you have hypothyroidism (decreased function of the thyroid) and you have received medication to correct for the reduced production of thyroxin. Read carefully the package insert that comes with your medicine. You should take the medicine in the morning on an empty stomach, about 15 minutes before breakfast. Don’t take medicines containing iron or calcium for 4 hours after you have taken thyroxin. You should talk with your doctor about taking thyroxin together with antacids and other medicines that are also taken on an empty stomach. Moderate use of dairy products, like yoghurt or milk in the coffee at breakfast, should not affect the uptake of thyroxin very much.
When giving a blood sample for thyroid lab values, remember to take the thyroxin tablets only after you have given the blood sample. Come to the lab on an empty stomach.
Your doctor has prescribed the starting and maintenance doses of thyroxin. These doses are tailored for you. Often the starting dose is smaller than the maintenance dose. When treatment is started, the dose is usually gradually increased until a dose that is just right for you been reached. Your doctor will check the thyroid values with blood tests. The first blood test is usually taken 2–3 months after treatment start and repeated when the dosage is changed. Your blood is tested for TSH and T4V. Hormone production by the thyroid is regulated by the pituitary. This gland produces TSH. In hypothyroidism, the production of TSH usually increases when the thyroid doesn’t produce enough hormones, and the production of free thyroxin (T4V) decreases. The goal of treatment is to have the TSH value decrease and the T4v value to increase and reach values within the normal range that fit your needs. Once the dosage of thyroxin is suitable, lab tests are needed once a year. The dose is suitable when you feel well, have no symptoms of hypothyroidism and the lab tests are normal.
After thyroxin treatment has started you will feel better maybe in just a few weeks. But be patient – keep in mind that you may have had hypothyroidism for many years and it may take some months, or even longer, before you feel okay. Usually patients with hypothyroidism need thyroxin for the rest of their lives.
You may feel your heart beat (palpitations) in the beginning of treatment and when the dose of thyroxin is increased. This usually passes. Please don’t change the dosage of your medication without first talking about it with your doctor. Dosage and treatment are individually tailored for each patient, and other diseases or medicines may affect your medication. That’s why it is important that you follow your doctor’s prescriptions and that you tell your doctor if your condition changes or if the treatment doesn’t seem to work as expected.
What’s the thyroid and why do I have hypothyroidism?
The thyroid is a gland that is located below your Adam’s apple, in the front of your throat. It weighs only about 20 grams (0.7 ounces). Although it is small, the thyroid is essential for metabolism and for the entire body. The thyroid is involved in body temperature control, alertness, gut function, mood and fat metabolism. To do all of this, the thyroid produces, stores and releases thyroid hormones into the blood circulation. The most important thyroid hormones are thyroxin (T4) and triiodothyronine (T3). When the thyroid functions normally, it produces T4 and T3 at a ratio of 4:1, i.e., about 80% T4 hormone and 20% T3 hormone. T4 is a prohormone. This means that it changes in the tissues of the body (e.g., liver and kidneys) into T3, which is the active hormone.
The usual reason for hypothyroidism is an autoimmune inflammation. Here, the body attacks its own tissues, in this case the thyroid, and disturbs its normal function. In rare cases, hypothyroidism may be due to a disease of the pituitary – the pituitary produces too little TSH and the thyroid gland is not activated to produce enough thyroid hormones.
Your doctor and Suomen Kilpirauhasliitto (the Finnish Thyroid Association) may provide more information about hypothyroidism. The web page of the Association is here: www.kilpirauhasliitto.fi and the telephone number is 044 7888 899. There is an automatic answering service which gives you the times when people are on duty.
Factual content approved in September 2015 by Leo Niskanen, specialist in internal medicine and endocrinology, Helsinki University Hospital.