What is Thyrosit?

Thyrosit is a replacement for a hormone that is normally produced by your thyroid gland to regulate the body’s energy and metabolism. Thyrosit is given when the thyroid does not produce enough of this hormone on its own.

Thyrosit treats hypothyroidism (low thyroid hormone). Thyrosit is also used to treat or prevent goiter (enlarged thyroid gland), which can be caused by hormone imbalances, radiation treatment, surgery, or cancer.

Thyrosit should not be used to treat obesity or weight problems.

Thyrosit may also be used for purposes not listed in this medication guide.

Thyrosit indications

Hypothyroidism

• Thyrosit is indicated in pediatric and adult patients as replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.
• Pituitary Thyrotropin (Thyroid-Stimulating Hormone, TSH) Suppression
• Thyrosit is indicated in pediatric and adult patients as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer.

Limitations of Use:

• Thyrosit is not indicated for suppression of benign thyroid nodules and nontoxic diffuse goiter in iodine-sufficient patients as there are no clinical benefits and overtreatment with Thyrosit may induce hyperthyroidism.
• Thyrosit is not indicated for treatment of hypothyroidism during the recovery phase of subacute thyroiditis.

How should I use Thyrosit?

Use Thyrosit solution as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• Thyrosit solution is usually given as an injection at your doctor’s office, hospital, or clinic. If you will be using Thyrosit solution at home, a health care provider will teach you how to use it. Be sure you understand how to use Thyrosit solution. Follow the procedures you are taught when you use a dose. Contact your health care provider if you have any questions.
• Do not use Thyrosit solution if it contains particles, is cloudy or discolored, or if the vial is cracked or damaged.
• Always carefully check that you have drawn up the correct dose before administration.
• Keep this product, as well as syringes and needles, out of the reach of children and pets. Do not reuse needles, syringes, or other materials. Ask your health care provider how to dispose of these materials after use. Follow all local rules for disposal.
• Thyrosit solution works best if you use it at the same time each day.
• Continue to use Thyrosit solution even if you feel well. Do not miss any doses.
• It may take several weeks before you notice an improvement in your symptoms. Do not stop or change your dose of Thyrosit solution without first checking with your doctor.
• If you miss a dose of Thyrosit solution, use it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not use 2 doses at once.

Ask your health care provider any questions you may have about how to use Thyrosit solution.

Uses of Thyrosit in details

Thyrosit is used to treat an underactive thyroid (hypothyroidism). It replaces or provides more thyroid hormone, which is normally produced by the thyroid gland. Low thyroid hormone levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery. Having enough thyroid hormone is important for maintaining normal mental and physical activity. In children, having enough thyroid hormone is important for normal mental and physical development.

This medication is also used to treat other types of thyroid disorders (such as certain types of goiters, thyroid cancer).

This medication should not be used to treat infertility unless it is caused by low thyroid hormone levels.

How to use Thyrosit

Take this medication by mouth as directed by your doctor, usually once daily on an empty stomach, 30 minutes to 1 hour before breakfast. Take this medication with a full glass of water unless your doctor directs you otherwise.

If you are taking the capsule form of this medication, swallow it whole. Do not split, crush, or chew. People who cannot swallow the capsule whole (such as infants or small children) should use the tablet form of the medication.

For infants or children who cannot swallow whole tablets, crush the tablet and mix in 1 to 2 teaspoons (5 to 10 milliliters) of water, and give using a spoon or dropper right away. Do not prepare a supply in advance or mix the tablet in soy infant formula. Consult your pharmacist for more information.

Dosage is based on your age, weight, medical condition, laboratory test results, and response to treatment.

Use this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time each day.

Do not stop taking this medication without first consulting with your doctor. Thyroid replacement treatment is usually taken for life.

There are different brands of Thyrosit available. Do not change brands without first consulting your doctor or pharmacist.

Certain medications (such as cholestyramine, colestipol, colesevelam, antacids, sucralfate, simethicone, iron, sodium polystyrene sulfonate, calcium supplements, orlistat, sevelamer, among others) can decrease the amount of thyroid hormone that is absorbed by your body. If you are taking any of these drugs, separate them from this medication by at least 4 hours.

Symptoms of low thyroid hormone levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heartbeat, or sensitivity to cold. Tell your doctor if your condition worsens or persists after several weeks of taking this medication.

Thyrosit description

1 tablet Thyrosit 25 μg contains 25 microgram Thyrosit.

1 tablet Thyrosit 50 μg contains 50 microgram Thyrosit.

1 tablet Thyrosit 75 μg contains 75 microgram Thyrosit.

1 tablet Thyrosit 100 μg contains 100 microgram Thyrosit.

Other Ingredients: Corn starch, croscarmellose sodium, gelatine, lactose monohydrate, magnesium stearate.

Thyrosit dosage

General PrinciplesThe goal of replacement therapy is to achieve and maintain a clinical and biochemical euthyroid state. The goal of suppressive therapy is to inhibit growth and/or function of abnormal thyroid tissue. The dose of Thyrosit™ (Thyrosit tablets) that is adequate to achieve these goals depends on a variety of factors including the patient’s age, body weight, cardiovascular status, concomitant medical conditions, including pregnancy, concomitant medications, and the specific nature of the condition being treated. Hence, the following recommendations serve only as dosing guidelines. Dosing must be individualized and adjustments made based on periodic assessment of the patient’s clinical response and laboratory parameters.

Thyrosit™ (Thyrosit tablets) should be taken in the morning on an empty stomach, at least one-half hour before any food is eaten. Thyrosit™ (Thyrosit tablets) should be taken at least 4 hours apart from drugs that are known to interfere with its absorption.

Due to the long half-life of Thyrosit, the peak therapeutic effect at a given dose of Thyrosit may not be attained for 4-6 weeks.

Caution should be exercised when administering Thyrosit™ (Thyrosit tablets) to patients with underlying cardiovascular disease, to the elderly, and to those with concomitant adrenal insufficiency.

Specific Patient PopulationsHypothyroidism in Adults and in Children in Whom Growth and Puberty are Complete

Therapy may begin at full replacement doses in otherwise healthy individuals less than 50 years old and in those older than 50 years who have been recently treated for hyperthyroidism or who have been hypothyroid for only a short time (such as a few months). The average full replacement dose of Thyrosit is approximately 1.7 mcg/kg/day (e.g., 100-125 mcg/day for a 70 kg adult). Older patients may require less than 1 mcg/kg/day. Thyrosit doses greater than 200 mcg/day are seldom required. An inadequate response to daily doses ≥ 300 mcg/day is rare and may indicate poor compliance, malabsorption, and/or drug interactions.

For most patients older than 50 years or for patients under 50 years of age with underlying cardiac disease, an initial starting dose of 25-50 mcg/day of Thyrosit is recommended, with gradual increments in dose at 6-8 week intervals, as needed. The recommended starting dose of Thyrosit in elderly patients with cardiac disease is 12.5-25 mcg/day, with gradual dose increments at 4-6 week intervals. The Thyrosit dose is generally adjusted in 12.5-25 mcg increments until the patient with primary hypothyroidism is clinically euthyroid and the serum TSH has normalized.

In patients with severe hypothyroidism, the recommended initial Thyrosit dose is 12.5-25 mcg/day with increases of 25 mcg/day every 2-4 weeks, accompanied by clinical and laboratory assessment, until the TSH level is normalized.

In patients with secondary (pituitary) or tertiary (hypothalamic) hypothyroidism, the Thyrosit dose should be titrated until the patient is clinically euthyroid and the serum free-T concentrations, the recommended initial starting dose is 50 mcg/day of Thyrosit.

Infants and ChildrenThyrosit therapy is usually initiated at full replacement doses, with the recommended dose per body weight decreasing with age. However, in children with chronic or severe hypothyroidism, an initial dose of 25 mcg/day of Thyrosit is recommended with increments of 25 mcg every 2-4 weeks until the desired effect is achieved.

Hyperactivity in an older child can be minimized if the starting dose is one-fourth of the recommended full replacement dose, and the dose is then increased on a weekly basis by an amount equal to one-fourth the full-recommended replacement dose until the full recommended replacement dose is reached.

Table 3: Thyrosit Dosing Guidelines for Pediatric Hypothyroidism

AGE Daily Dose Per Kg Body Weight The dose should be adjusted based on clinical response and laboratory parameters (see PRECAUTIONS, Laboratory Tests and Pediatric Use).Pregnancy– Pregnancy may increase Thyrosit requirements.

Subclinical Hypothyroidism– If this condition is treated, a lower Thyrosit dose (e.g., 1 mcg/kg/day) than that used for full replacement may be adequate to normalize the serum TSH level. Patients who are not treated should be monitored yearly for changes in clinical status and thyroid laboratory parameters.

TSH Suppression in Well-differentiated Thyroid Cancer and Thyroid Nodules – The target level for TSH suppression in these conditions has not been established with controlled studies. In addition, the efficacy of TSH suppression for benign nodular disease is controversial. Therefore, the dose of Thyrosit™ (Thyrosit tablets) used for TSH suppression should be individualized based on the specific disease and the patient being treated. In the treatment of well-differentiated (papillary and follicular) thyroid cancer, Thyrosit is used as an adjunct to surgery and radioiodine therapy. Generally, TSH is suppressed to < 0.1 mU/L, and this usually requires a Thyrosit dose of greater than 2 mcg/kg/day.

Thyrosit interactions

Protease Inhibitors: Protease inhibitors (e.g. ritonavir, indinavir, lopinavir) may influence the effect of Thyrosit. Close monitoring of thyroid hormone parameters is recommended. If necessary, the Thyrosit dose has to be adjusted.

Phenytoin: Phenytoin may influence the effect of Thyrosit by displacing Thyrosit from plasma proteins resulting in an elevated fT4 and fT3 fraction. On the other hand, phenytoin increases the hepatic metabolization of Thyrosit. Close monitoring of thyroid hormone parameters is recommended.

Influence of Thyrosit on Other Medicinal Products: Antidiabetic Medicinal Products: Thyrosit may reduce the effect of antidiabetics. Therefore, it is necessary to check blood glucose levels frequently at the start of thyroid hormone therapy. If necessary, the anti-diabetic dose has to be adjusted.

Coumarin Derivates: Thyrosit may intensify the effect of anticoagulants by displacing them from plasma protein bounds, which may increase the risk of hemorrhage e.g. CNS or gastrointestinal bleeding, especially in elderly patients. Therefore, it is necessary to check the coagulation parameters regularly at the start of and during concomitant therapy. If necessary, the anticoagulant dose has to be adjusted.

The Following Medicinal Products Intensify the Effect of Thyrosit: Salicylates, dicumarol, furosemide, clofibrate;

Salicylates, dicumarol, furosemide in high doses (250 mg), clofibrate, and other substances can displace Thyrosit from plasma proteins, resulting in an elevated fT4 fraction.

The Following Medicinal Products May Reduce the Effect of Thyrosit: Orlistat: Hypothyroidism and/or reduced control of hypothyroidism may occur when orlistat and Thyrosit are taken at the same time. This could be due to a decreased absorption of iodine salts and/or Thyrosit.

Sevelamer: Sevelamer may decrease Thyrosit absorption. Therefore, it is recommended that patients are monitored for changes in thyroid function at the start or end of concomitant treatment. If necessary, the Thyrosit dose has to be adjusted.

Tyrosine kinase inhibitors: Tyrosine kinase inhibitors (e.g. imatinib, sunitinib) may decrease the efficacy of Thyrosit. Therefore, it is recommended that patients are monitored for changes in thyroid function at the start or end of concomitant treatment. If necessary, the Thyrosit dose has to be adjusted.

Ion exchange resins: Ion exchange resins (e.g. cholestyramine or colestipol) inhibit the absorption of Thyrosit. It is therefore recommended that Thyrosit be taken 4 – 5 hours before the administration of such agents.

Aluminum containing medicinal products, iron-containing medicinal products, calcium carbonate: Aluminium-containing medicinal products (antacids, sucralfate) have been reported in the literature as potentially decreasing the effect of Thyrosit. It is therefore recommended that Thyrosit be administered at least 2 hours prior to the administration of aluminum-containing medicinal products. The same applies to iron-containing medicinal products and calcium carbonate.

Propylthiouracil, glucocorticoids, beta-sympatholytics, and iodine-containing contrast media: These substances inhibit the peripheral conversion of T4 to T3.

Amiodarone: This substance inhibits the peripheral conversion of T4 to T3.

Due to its high iodine content amiodarone can trigger hyperthyroidism as well as hypothyroidism. Particular caution is advised in the case of nodular goiter with possibly unrecognized autonomy.

Sertraline, chloroquine/proguanil: These substances decrease the efficacy of Thyrosit and increase the serum TSH level.

Medicinal Products Leading to Hepatic Enzyme Induction (e.g. Barbiturates, Carbamazepine): These substances can increase the hepatic clearance of Thyrosit.

Oestrogens: Women using estrogen-containing contraceptives or postmenopausal women under hormone-replacement therapy may have an increased need for Thyrosit.

Interaction with Food: Soy containing compounds: Soy containing compounds can decrease the intestinal absorption of Thyrosit. Therefore, a dosage adjustment of Thyrosit may be necessary, in particular at the beginning or after the termination of nutrition with soy supplements.

Thyrosit side effects

Since the thyroid hormone occurs naturally in the body, almost anyone can take Thyrosit. You should not use this medication if you have had a heart attack, a thyroid disorder called thyrotoxicosis, or an adrenal gland problem that is not controlled by treatment.

Before you take Thyrosit, tell your doctor if you have a serious thyroid disorder (thyrotoxicosis), heart disease, coronary artery disease, diabetes, anemia, problems with your pituitary or adrenal glands, a history of blood clots, if you have recently had a heart attack, or if you are having any symptoms of a heart attack (chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling).

If you use insulin or take diabetes medicine by mouth, ask your doctor if your dose needs to be changed when you start using Thyrosit.

Different brands of Thyrosit may not work the same. If you get a prescription refill and your new pills look different, talk with your pharmacist or doctor.

It may take several weeks before your body starts to respond to this medication. Do not stop taking the medicine suddenly, even if you feel well.

Many other medicines can be affected by your thyroid hormone levels. Other medicine may also increase or decrease the effects of Thyrosit. Tell your doctor about all medications you use, start using, or stop using during your treatment with Thyrosit. This includes prescription, over-the-counter, vitamin, and herbal products. Keep a list of all your medicines and show it to any healthcare provider who treats you.