L-thyroxine for hypothyroidism

L-thyroxine (levothyroxine) is primarily used to treat an underactive thyroid. In addition, the hormone can also be used to treat goitre (goitre) and, in exceptional cases, hyperthyroidism. Usually, Thyroxine is well tolerated, so no side effects occur during therapy. Find out here in detail about the hormone’s effect and dosage and why Thyroxine should not be used to lose weight.

Thyroxine: action in the body

Thyroxine is an endogenous hormone that is produced in the thyroid gland. Along with triiodothyronine, another thyroid hormone, it is involved in various processes in the body, including metabolism.

 

L-thyroxine for hypothyroidism

When the thyroid gland is underactive (hypothyroidism), the body produces too little Thyroxine. This can lead to symptoms such as tiredness, listlessness and problems concentrating. To treat such symptoms, L-thyroxine is administered to the body.

In addition to hypothyroidism, there are other areas of application for L-thyroxine. The hormone is also administered.

• If you have a benign enlargement of the thyroid gland (goitre).
• To prevent goitre from forming again after successful goitre surgery.
• If a patient suffers from a malignant thyroid tumour.
• If normal thyroid gland function has been achieved again in patients with an overactive thyroid gland (here, the hormone is used together with antithyroid drugs).

Thyroxine side effects

Thyroxine is generally considered well-tolerated, so side effects rarely occur.

If the level of the dose is not tolerated or if there is an overdose, the typical symptoms of an overactive thyroid can occur. These include signs such as:

• palpitations and cardiac arrhythmia
• feeling hot and sweating
• Tremble
• inner unrest
• insomnia

You should always contact your doctor if you experience side effects while taking Thyroxine. Reducing the dose for a few days or stopping taking the tablets altogether may make sense. Once the side effects have subsided, treatment can be restarted at a lower dose.

 

Important to take

People with an underactive thyroid usually have to take a hormone replacement drug for the rest of their lives. If a benign goitre is treated, the duration of intake is usually between six months and two years.

You should take the Thyroxine tablet whole in the morning at least half an hour before breakfast. As a result, the hormone, which is generally poorly absorbable, can be better absorbed by the body. Swallow the tablet with some water but not coffee.

Dosing of Thyroxine

The exact dosage of Thyroxine always depends on the cause of the treatment, i.e. whether, for example, an underactive thyroid is being treated or a new goitre is being prevented. If an underactive thyroid is to be treated, the dosage depends on the severity of the disease.

If you have an underactive thyroid, start with a low dose, which can be increased if necessary. A low starting dose is essential, especially for patients who suffer from severe or long-standing hypothyroidism. However, a low starting dose should also be selected for older or very slim people and patients who have coronary artery disease.

In the case of hypothyroidism, a dose of between 25 and 50 micrograms is often started. This can be slowly increased to a maximum of 100 to 200 micrograms. In children, the dosage depends not only on the age but also on the child’s weight. You should always follow your doctor’s instructions for dosing Thyroxine.

Avoid overdosing

If you have taken an overdose of Thyroxine, it can trigger the typical symptoms of an overactive thyroid. This is accompanied, among other things, by signs such as palpitations and cardiac arrhythmias, feeling hot and excessive sweating, inner restlessness, tremors and insomnia.

If you need to remember a tablet, you should not take the dose because of this. Instead, stick to the prescribed intake rhythm.

An overdose can result not only from taking too many tablets but also from an incorrectly set dose. That’s why a doctor should check your thyroid levels regularly. The thyrotropin value is significant here since thyrotropin stimulates the formation of Thyroxine. Such examinations are critical in the adjustment phase, during pregnancy and when the dose changes.

 

Interactions with Thyroxine

Some medications inhibit or reduce L-thyroxine absorption and should, therefore, not be taken together with the hormone. These drugs include cholestyramine and colestipol. This also applies to gastric acid-binding antacids, calcium carbonate and medicines that contain iron.

In addition, agents such as glucocorticoids, beta-blockers, iodinated contrast media and propylthiouracil ensure that L-thyroxine is less able to be converted into its more effective form in the body.

In addition, interactions with the following medications can occur while taking Thyroxine:

• Phenytoin
• Salicylate
• Dicumarol
• Furosemide
• Clofibrate
• Sertraline
• Chloroquine
• Proguanil
• Barbiturate
• Amiodarone

For women who take birth control pills, it must be taken into account that this can increase the need for L-thyroxine. The same applies to women who undergo hormone replacement therapy after menopause.

Influence on other drugs

The effect of Thyroxine is not only increased or inhibited by other drugs but can also influence other active ingredients. Coumarin derivatives, which inhibit blood clotting, are primarily affected. The thyroid hormone enhances its effect.

L-thyroxine has the opposite effect on drugs that lower blood sugar . These are weakened in their effect.

Interactions with food

In addition to medication, there can also be interactions with certain foods. You should not take the hormones at the same time as a cup of coffee, as this inhibits absorption into the blood, and the hormone concentration in the blood can drop significantly.

Soy products can also impede the absorption of L-thyroxine from the intestine. If you eat soy products more frequently, you should tell your doctor.

 

Thyroxine contraindications

L-thyroxine must not be used if there is hypersensitivity to the active ingredient. Likewise, the hormone must not be taken by patients with untreated hyperthyroidism.

In addition, the tablets must not be prescribed for the following diseases:

• recent myocardial infarction or acute myocardial or cardiac wall inflammation
• untreated adrenal insufficiency
• untreated weakness of the pituitary gland
• autonomy of the thyroid