L-thyroxine (syn. Levothyroxine, T4) is a synthetically produced thyroid hormone. It replaces the thyroxine (T4) present in the human body, which is a precursor of the second thyroid hormone triiodothyronine (T3).
The thyroid hormones are important for the development and function of the entire organism. They are mainly needed for the maturation of the brain. Among other things, they influence the nervous system and psyche and the growth of skin, hair and nails.
They also play an essential role in energy metabolism and control the function of the stomach and intestines, heart and circulation. One drug that contains L-thyroxine, among other things, is Thyronajod®. L-thyroxine is required for the treatment of hypothyroidism.
People with this disease often suffer from the following symptoms: These symptoms are not pronounced in all patients suffering from hypothyroidism. Older people in particular often show few typical characteristics of this disease. The treatment of hypothyroidism involves compensating for the lack of thyroid hormone and thus reducing the symptoms.
In addition, the hormones used in this therapy are also used after removal of the thyroid gland as part of a thyroid cancer treatment and also to strengthen the classic antidepressants in the treatment of depression. The thyroid hormones are supplied to the human body in tablet form. In most cases, this treatment must be administered for a lifetime.
- Weight gain
- Constant fatigue
- Sensitivity to cold
- Weakness of memory
- Depressive moods
- Muscular weakness
- Cool, pale and dry skin
- Brittle, brittle hair up to increased hair loss
- Brittle nails
- Chronic constipation
- Goiter (Struma)
- Cycle disorders in women
- Reduction of sexual desire and potency in men
- Swelling of the subcutaneous fatty tissue (so-called myxedema)
Effect
L-thyroxine has the same structure as an endogenous thyroid hormone. Therefore it works in the same way as the thyroid hormones. The main effect is to increase the drive and activity of the body.
This is done by L-thyroxine activating signaling pathways inside the cells, which activate the metabolism. For example, the breakdown of fats and carbohydrates is stimulated to provide energy. Consequently, the basal metabolic rate increases when taking L-thyroxine.
L-thyroxine also increases activity in the heart. Here, the signaling pathways triggered by L-thyroxine lead to increased incorporation of so-called beta receptors. These receptors increase the strength and beat rate of the heart when they are activated.
In children, thyroid hormones and thus, if necessary, L-thyroxine are important for growth and maturation. In doing so, they promote developmental processes in nerves and bones, for example. When L-thyroxine is taken for the first time, the effect occurs after one to three weeks.
Until this time, the amount of L-thyroxine in the blood increases slowly due to the intake. The body can thus adapt its functions and metabolism to the new hormone level. In order to maintain the effect over the long term, L-thyroxine must be taken regularly in the dosage prescribed by the doctor.
In this article you will find information about other medications as a therapy for hypothyroidism: Thyroid medicationsThyroxine tablets are taken with the synthetically produced thyroxine (T4), which corresponds to the human thyroid hormone thyroxine. L-thyroxine is preferred to the intake of the other thyroid hormone T3 because it has a longer retention time in the body. T3 is then automatically produced in the body from T4 in the required amount.
It should be taken 30 minutes before a meal so as not to reduce absorption in the intestines through food. The therapy is started gradually, i.e. it is started with a low dose (usually 25-50 μg) and then slowly increased (usually 75-200μg). The individually correct dose is determined by creeping in and the accompanying blood tests.
The need for L-thyroxine depends on the age of the patient and decreases with age. The need can also vary greatly from one individual to another. Patients can lead a completely normal life if taken correctly.
Blood tests are performed about once a month at the beginning of treatment.When the hormone levels in the blood have normalized, the examination is performed every three to six months. Due to the long half-life of L-thyroxine of 190 hours, there are no significant consequences if the intake is forgotten. The therapy is then continued as usual on the following day.
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