How Thyroxine / Levothyroxine works

Thyroxine / Levothyroxine is a synthetic version of a hormone produced by the thyroid gland. It works by replacing the thyroid hormones that your thyroid gland cannot produce and relieves the symptoms of hypothyroidism (tiredness, weight gain, and depression).

Side Effects

Anxiety, Vomiting, Diarrhoea, Palpitations, Nervousness, Weight loss, Tremor

Usage

Thyroxine / Levothyroxine is used in the treatment of hypothyroidism.

Frequently Asked Questions

Q. Can I take Thyroxine / Levothyroxine during pregnancy?

Thyroid hormone is naturally present in the body and is therefore safe to take in pregnancy. In fact, it is very important that pregnant women or those planning to become pregnant have normal thyroid hormone levels to provide a suitable environment for the baby. If you are already taking thyroid hormone, your dose may need to be increased during pregnancy. Hence, you may have to get your thyroid hormone and TSH levels measured once you know that you are pregnant. You should discuss the timing of thyroid blood tests with your doctor, but often thyroid tests are done every trimester.

Q. Does Thyroxine / Levothyroxine interact with any other medications?

Use of medications such as birth control pills, estrogen, testosterone, some medications for seizures, depression, and cholesterol, and supplements such as iron and calcium may require you to alter the dose of Thyroxine / Levothyroxine. It is therefore important that you let your doctor know about all the medications or supplements you are taking.

Q. What is the dose for Thyroxine / Levothyroxine?

The dose is individualised on the basis of clinical response and biochemical tests. Regular monitoring of thyroid stimulating hormone (TSH) and Thyroxine / Levothyroxine is recommended when starting therapy or changing the dose. Do not change the dose or stop the medicine without consulting your doctor.

Q. Can I take Thyroxine / Levothyroxine with tea/coffee/food?

It is best to take Thyroxine / Levothyroxine on an empty stomach (ideally, first thing in the morning). No tea/coffee, food or milk should be taken 1 hour before and 2 hours after taking this medicine as it affects its absorption.

Q. What happens if we consume too much iodine?

In some people, increased dietary iodine intake causes the thyroid gland to make excess of thyroid hormone, leading to a condition called iodine-induced hyperthyroidism. Too much of iodine can also cause thyroid underactivity, called hypothyroidism as excess iodine blocks the thyroid's ability to produce the hormone.

Q. Is Thyroxine / Levothyroxine a beta blocker?

No. Thyroxine / Levothyroxine is not a beta-blocker. It is a hormone synthesised by the thyroid gland present in the neck region. It maintains normal growth & development, body temperature & energy levels.

Q. Is Thyroxine / Levothyroxine a blood thinner?

No. Thyroxine / Levothyroxine is not a blood thinner. It is a hormone used for the treatment of hypothyroidism (decreased thyroid hormone). Blood thinners are medicines which prevent abnormal clot formation.

Q. Does Thyroxine / Levothyroxine cause weight loss?

Yes. Thyroxine / Levothyroxine can produce side effect as weight loss. It is usually due to excessive dose. However, it should not be used for treat obesity.

Q. Is Thyroxine / Levothyroxine a growth hormone?

No, Thyroxine / Levothyroxine is not a growth hormone. It is a hormone synthesized by the thyroid gland present in the neck region. Growth Hormone, on the other hand, is secreted by the pituitary gland present in the brain. Thyroxine / Levothyroxine is required for the proper functioning of growth hormone.

Q. Is Thyroxine / Levothyroxine a neurotransmitter?

No, Thyroxine / Levothyroxine is not a neurotransmitter. Thyroxine / Levothyroxine is a hormone secreted directly into the blood by the thyroid gland. The blood then takes it to the target organs in the body. A neurotransmitter, on the other hand, transmits impulses from one nerve cell to the other in the brain.

Q. Is Thyroxine / Levothyroxine a tropic hormone?

Tropic hormones are hormones that have other endocrine glands as their target. Most tropic hormones are produced and secreted by the pituitary gland in the brain. The thyroid gland secretes Thyroxine / Levothyroxine, which targets the hypothalamus and therefore can be considered a tropic hormone.

Q. Is Thyroxine / Levothyroxine a protein?

No. Thyroxine / Levothyroxine is not a protein. The normal thyroid gland secretes two thyroid hormones - triiodothyronine (T3) and tetraiodothyronine (T4 or Thyroxine / Levothyroxine). More than 99% of these hormone circulating in the blood as bound to carrier proteins, Thyroxine / Levothyroxine-binding globulin, synthesised in the liver.

Q. Is Thyroxine / Levothyroxine a peptide or steroid?

Thyroxine / Levothyroxine is neither a peptide nor a steroid. Thyroxine / Levothyroxine is an amino acid (tyrosine) derived hormone. (Amino acids are tiny building blocks of proteins, but they cannot be called proteins by themselves unless a number of them are connected in a sequence).

Q. Can Thyroxine / Levothyroxine be used as hormone replacement therapy?

Yes. Thyroxine / Levothyroxine can be used as a hormone replacement therapy to compensate the deficiency of thyroid hormone in the body.

Q. Is Thyroxine / Levothyroxine a hormone?

Yes. Thyroxine / Levothyroxine is a hormone secreted from the thyroid gland. It causes increased oxygen consumption by most tissues of the body, increases the basal metabolic rate and the metabolism of carbohydrates, lipids and proteins.

Q. Is Thyroxine / Levothyroxine a slowly acting drug?

Yes. Thyroxine / Levothyroxine is a slow-acting drug. It acts through receptors situated in the nucleus of a cell and results in the formation of various protein to target its action hence Thyroxine / Levothyroxine takes some time to act.

Q. Is Thyroxine / Levothyroxine a diuretic?

No. Thyroxine / Levothyroxine is not a diuretic. It is a hormone secreted by the thyroid gland.

Q. What is Thyroxine / Levothyroxine poisoning?

Thyroxine / Levothyroxine poisoning occur if an excessive dose is taken. It present as a headache, hyperactivity, nervousness, anxiety, irritability, heat intolerance, fever, excessive sweating, palpitations, tachycardia, arrhythmias, increased pulse and blood pressure. Inform your doctor as soon as possible.

Q. How Thyroxine / Levothyroxine modulates erythropoiesis?

Thyroxine / Levothyroxine is required for the normal functioning of the body. Research has shown that thyroid hormone significantly affects the erythropoiesis and increases red blood cell synthesis. Thyroxine / Levothyroxine is not approved to treat anemia (decreased red cell count).

Q. In which condition does Thyroxine / Levothyroxine is used along with carbimazole?

Thyroxine / Levothyroxine is used with carbimazole in the treatment of Graves disease or hyperthyroidism. Studies have shown it is used as block–replace regimen which means the option of maintaining the high dose of antithyroid drugs along with adding levothyroxine to maintain normal thyroid state.

Q. Can I take an antidepressant along with Thyroxine / Levothyroxine?

No. There are noted interactions between Thyroxine / Levothyroxine and few antidepressants which lead to increased adverse effects of both the drugs so consult your doctor and do inform him before prescribing any of the medication.

Q. What is the effect of grapefruit juice on the absorption of Thyroxine / Levothyroxine?

Grapefruit juice slightly decreases the absorption of levothyroxine when taken together otherwise there is no major interaction between these two.

Q. Can I take vitamins with Thyroxine / Levothyroxine and what would be its effects?

Yes. Vitamins can be added to your diet and can be taken with Thyroxine / Levothyroxine, but you should not take vitamin supplement within four hours of taking your thyroid medication.

Q. Can I take omeprazole along with Thyroxine / Levothyroxine?

No. Omeprazole should not be taken with Thyroxine / Levothyroxine. Omeprazole increases the gastric pH and interferes with the absorption of the Thyroxine / Levothyroxine.

Q. Can I take Thyroxine / Levothyroxine with iron tablets?

No. Thyroxine / Levothyroxine should not be taken with the iron tablet. The absorption of Thyroxine / Levothyroxine is decreased when taken together. You should take them with a gap of 4 hours between them.

Q. Can I take Thyroxine / Levothyroxine with calcium?

No. Thyroxine / Levothyroxine should not be taken with calcium. The absorption of Thyroxine / Levothyroxine is decreased when taken with calcium. You should take them with a gap of 4 hours between them.

Q. Can Thyroxine / Levothyroxine be used in the treatment obesity?

No. Thyroxine / Levothyroxine should not be used to treat obesity. It can cause weight loss as a side effect but it should not be used for the treatment of obesity as it can cause serious life-threatening side effects if given with other weight reducing medications.

Q. Can Thyroxine / Levothyroxine be used in the treatment of depression?

No. Thyroxine / Levothyroxine is not approved for use in depression. But some of the research studies have shown that adding Thyroxine / Levothyroxine to the antidepressant medication therapy has increased the effectiveness of antidepressant therapy in the patients.

Q. Can Thyroxine / Levothyroxine help you get pregnant?

Thyroxine / Levothyroxine treats hypothyroidism (decreased thyroid hormone) and associated complications leading to increases chances of conceiving. Consult your doctor before starting Thyroxine / Levothyroxine as failure to conceive is not merely due to decreased thyroid hormone but due to several other factors. Always start the medicine consulting with the doctor.

Q. Should I take Thyroxine / Levothyroxine in morning or evening?

It is preferred to take Thyroxine / Levothyroxine in morning on empty stomach. Research has shown that even if it is given in the evening, it shows the same effects as compared to morning. It is not practised because of ensuring an empty stomach by the patient.

Q. Is it safe to take Thyroxine / Levothyroxine if I have a cardiac disease?

Yes. Thyroxine / Levothyroxine can be used but at a lower dose or given on an alternate day. There are high chances of side effects in a person with the cardiac disease like an increase in heart rate, cardiac wall thickness, and cardiac contractility and it may precipitate angina or irregular heart rhythms. Inform your doctor if you have heart disease. You may adjust the dose.

Q. What are the serious side effects of Thyroxine / Levothyroxine?

The serious side effects of Thyroxine / Levothyroxine are usually due to excessive doses, so symptoms are similar to hyperthyroidism. It may cause diarrhoea, vomiting, weight loss with increased appetite, palpitations, angina, insomnia and restlessness. Inform your doctor if you have these symptoms.

Q. Can I take antacids with Thyroxine / Levothyroxine?

No. Thyroxine / Levothyroxine should not be taken with an antacid. The absorption of Thyroxine / Levothyroxine is decreased when taken together. You should take them with a gap of 4 hours between them.

Q. When should I get thyroid function test after starting Thyroxine / Levothyroxine?

Thyroid function test should be measured three months after starting treatment or change in dose.

Q. Can Thyroxine / Levothyroxine be taken along with MAO inhibitor?

Yes. Thyroxine / Levothyroxine can be taken with MAO inhibitors. Consult your doctor before starting these medications.