Cytomel

DRUG DESCRIPTION

Thyroid hormone drugs are natural or synthetic preparations containing tetraiodothyronine (T4, levothyroxine) sodium or triiodothyronine (T3, liothyronine) sodium or both. T4 and T3 are produced in the human thyroid gland by the iodination and coupling of the amino acid tyrosine. T4 contains four iodine atoms and is formed by the coupling of two molecules of diiodotyrosine (DIT). T3 contains three atoms of iodine and is formed by the coupling of one molecule of DIT with one molecule of monoiodotyrosine (MIT).

Both hormones are stored in the thyroid colloid as thyroglobulin.

Thyroid hormone preparations belong to two categories: (1) natural hormonal preparations derived from animal thyroid, and (2) synthetic preparations. Natural preparations include desiccated thyroid and thyroglobulin. Desiccated thyroid is derived from domesticated animals that are used for food by man (either beef or hog thyroid), and thyroglobulin is derived from thyroid glands of the hog. The United States Pharmacopeia (USP) has standardized the total iodine content of natural preparations. Thyroid USP contains not less than (NLT) 0.17 percent and not more than (NMT) 0.23 percent iodine, and thyroglobulin contains not less than (NLT) 0.7 percent of organically bound iodine. Iodine content is only an indirect indicator of true hormonal biologic activity. Cytomel (liothyronine sodium) (liothyronine sodium) Tablets contain liothyronine (L-triiodothyronine or LT3), a synthetic form of a natural thyroid hormone, and is available as the sodium salt.

The structural and empirical formulas and molecular weight of liothyronine sodium are given below.

Liothyronine Sodium

CYTOMEL (liothyronine sodium)  Structural Formula Illustration

C15H11I3NNaO4 M.W.672.96

L-Tyrosine, O-(4-hydroxy-3-iodophenyl)-3,5-diiodo-, monosodium salt

Twenty-five mcg of liothyronine is equivalent to approximately 1 grain of desiccated thyroid or thyroglobulin and 0.1 mg of Lthyroxine.

Each round, white to off-white Cytomel (liothyronine sodium) tablet contains liothyronine sodium equivalent to liothyronine as follows: 5 mcg debossed KPI and 115; 25 mcg scored and debossed KPI and 116; 50 mcg scored and debossed KPI and 117. Inactive ingredients consist of calcium sulfate, gelatin, starch, stearic acid, sucrose and talc.

What are the possible side effects of liothyronine (Cytomel)?

Stop using liothyronine and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects may include temporary hair loss (especially in children).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at...

Read All Potential Side Effects and See Pictures of Cytomel

What are the precautions when taking liothyronine sodium (Cytomel)?

Before taking liothyronine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: decreased adrenal gland function, kidney disease (e.g., nephrosis), low pituitary hormone (e.g., hypopituitarism), low testosterone (e.g., hypogonadism), overactive thyroid (hyperthyroidism).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (e.g., angina, high blood pressure, heart failure, irregular...

Read All Potential Precautions of Cytomel


Cytomel Consumer (continued)

SIDE EFFECTS: Nausea may occur. In rare instances, some temporary hair loss may occur during the first few months of starting this drug (especially in children). If any of these effects persist or worsen, notify your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Though unlikely, it is possible to have too much thyroid hormone. Tell your doctor immediately if any of these unlikely but serious signs of too much thyroid hormone occur: headache, irritability, trouble sleeping, nervousness, increased sweating, heat intolerance, diarrhea, menstrual changes.

Seek immediate medical attention if any of these rare but very serious side effects occur: chest pain, trouble breathing with exercise, fast/irregular/pounding heartbeat, swelling of the arms/legs, extreme weakness.

A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking liothyronine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist if you have: decreased adrenal gland function, kidney disease (e.g., nephrosis), low pituitary hormone (e.g., hypopituitarism), low testosterone (e.g., hypogonadism), overactive thyroid (hyperthyroidism).

Before using this medication, tell your doctor or pharmacist your medical history, especially of: heart disease (e.g., angina, high blood pressure, heart failure, irregular heartbeat, heart attack), sugar diabetes (diabetes mellitus), water diabetes (diabetes insipidus), long-term severe underactive thyroid (e.g., myxedema).

Before having surgery, tell your doctor or dentist that you are using this medication.

If you have diabetes, this drug may make it harder to control your blood sugar levels. Check your blood sugar regularly as directed by your doctor. Tell your doctor immediately if you have symptoms such as increased thirst/urination, shakiness, unusual sweating, or hunger. Your anti-diabetic medication or diet may need to be adjusted.

Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at a greater risk for heart problems while using this drug.

Children may be more sensitive to the effects of thyroid hormones.

Current information shows that this drug may be used during pregnancy. Consult your doctor before becoming pregnant.

Liothyronine passes into breast milk. While there have been no reports of harm to nursing infants, consult your doctor before breast-feeding.


Cytomel Patient Information Including Side Effects

Brand Names: Cytomel

Generic Name: liothyronine (Pronunciation: LYE oh THYE roe neen)

  • What is liothyronine (Cytomel)?
  • What are the possible side effects of liothyronine (Cytomel)?
  • What is the most important information I should know about liothyronine (Cytomel)?
  • What should I discuss with my healthcare provider before taking liothyronine (Cytomel)?
  • How should I take liothyronine (Cytomel)?
  • What happens if I miss a dose (Cytomel)?
  • What happens if I overdose (Cytomel)?
  • What should I avoid while taking liothyronine (Cytomel)?
  • What other drugs will affect liothyronine (Cytomel)?
  • Where can I get more information?

What is liothyronine (Cytomel)?

Liothyronine is a man-made form of a hormone that is normally produced by your thyroid gland to regulate the body's energy and metabolism. Liothyronine is given when the thyroid does not produce enough of this hormone on its own.

Liothyronine treats hypothyroidism (low thyroid hormone). Liothyronine is also used to treat or prevent goiter (enlarged thyroid gland), and is also given as part of a medical tests for thyroid disorders.

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

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

What are the possible side effects of liothyronine (Cytomel)?

Stop using liothyronine and get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects may include temporary hair loss (especially in children).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the most important information I should know about liothyronine (Cytomel)?

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

Before taking liothyronine, tell your doctor if you have heart disease, angina (chest pain), coronary artery disease, congestive heart failure, diabetes, or problems with your pituitary or adrenal glands.

Tell your doctor if you are pregnant or breast-feeding.

To be sure this medication is helping your condition, your blood may need to be tested on a regular basis. Do not miss any follow-up visits to your doctor.

Keep using this medicine as directed, even if you feel well. You may need to use this medication for the rest of your life.

Call your doctor if you notice any signs of thyroid toxicity, such as chest pain, fast or pounding heartbeats, feeling hot or nervous, or sweating more than usual.

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