Levothyroxine

This page contains recent news articles, when available, and an overview of Levothyroxine but does not offer medical advice. You should contact your physician with regard to any health issues or concerns.


Overview:

Levothyroxine
(when available)

Pharmacology and use:
Levothyroxine (T4) is a synthetically prepared levo isomer of thyroxine, a hormone secreted by the thyroid gland. Levothyroxine is used alone or in combination with antithyroid agents to treat hypothyroidism, goiter, chronic lymphocytic thyroiditis, myxedema coma, or stupor. For use as replacement or supplemental therapy in patients of any age or state (including pregnancy) with hypothyroidism of any etiology except transient hypothyroidism during the recovery phase of subacute thyroiditis or primary hypothyroidism resulting from thyroid dysfunction.

Mechanism Of Action:
Levothyroxine acts like the endogenous thyroid hormone thyroxine (T4, a tetra-iodinated tyrosine derivative). In the liver and kidney, T4 is converted to T3, an active metabolite. In order to increase solubility, the thyroid hormones attach to thyroid hormone binding proteins, thyroxin-binding globulin and thyroxin-binding prealbumin (transthyretin). Transport to thyroid hormone receptors in the cytoplasm and nucleus then takes place.

News Articles on Levothyroxine

Brand Name Levothyroxine at Generic Prices  -  ‎Aug 26, 2009‎
Because a small change in the absorption of levothyroxine may make a big difference in both thyroid function tests and how the patient feels, Dr. Friedman EmpowHer

Is the FDA Planning to Get Rid of Desiccated Thyroid Drugs Like ...  -  ‎Aug 19, 2009‎
The synthetic thyroid drug levothyroxine, however, has gone through the NDA process. Back in 1997, stability and potency problems with levothyroxine drugs About - News & Issues

Medco Thyroid Scandal: Medco Misleadingly Says They Were "Notified ...  -  ‎Aug 11, 2009‎
Please understand that Medco is not favoring levothyroxine treatments over desiccated thyroid drugs. We mention levothyroxine treatments in our About - News & Issues

Medco Thyroid Scandal: Thyroid Patients Demand Answers Regarding ...  -  ‎Aug 6, 2009‎
You then go on to indicate, "When prescribing thyroid therapy consider using levothyroxine." Frankly, patients around the United States -- and in particular About - News & Issues

About the Cover  -  ‎Aug 5, 2009‎
18 F]-fluorodeoxyglucose positron emission tomography in hypothyroid patients before (top row) and after (bottom row) 3 months of levothyroxine therapy. Journal of Clinical Endocrinology and Metabolism

Doctor, Doctor: Treating an underactive thyroid  -  ‎Aug 4, 2009‎
The standard treatment is to replace the low levels of thyroid hormone with levothyroxine (synthetic thyroid hormone). This tablet is taken daily and after Herald.ie

Dr. Keith Berndtson's Shares His Approach to the Natural ...  -  ‎Aug 27, 2009‎
...natural thyroid drugs, Dr. Berndtson's letter explains why he needs to switch them to levothyroxine plus Cytomel, and the conversion ratio he has used. About - News & Issues

Sluggish thyroid cause of high cholestrol?  -  ‎Aug 19, 2009‎
Your doctor will most likely prescribe levothyroxine, which acts as a replacement for thyroid hormone. The American Association of Clinical Endocrinologists Examiner.com

Fatalities Associated With Clozapine-Related Constipation and ...  -  ‎Aug 17, 2009‎
He was also taking glyburide (2.5 mg every morning and 5 mg at bedtime) and levothyroxine (0.075 mg daily). On Day 16, he reported not having had a bowel Psychosomatics (subscription)

The balance between clinical judgment and a patient's right to choose  -  ‎Aug 4, 2009‎
The patient's past medical history included mild menopausal symptoms and a 14-year history of hypothyroidism, for which she took daily levothyroxine. Clinical Advisor

READERS RESPOND  -  ‎Aug 11, 2009‎
Her medications include lisinopril, 10 mg/d; buspirone, 10 mg twice daily; levothyroxine, 0.125 mg/d; and naproxen, 500 mg twice daily. Journal of American Medical Association (subscription)

Brain Glucose Metabolism in Hypothyroidism: A Positron Emission ...  -  ‎Aug 5, 2009‎
Effects of thyroid hormone replacement therapy (levothyroxine, 3 months) were assessed using neuropsychiatric measures and positron emission tomography with Journal of Clinical Endocrinology and Metabolism

Thyroid drug funded  -  ‎Aug 12, 2009‎
The public pharmaceutical management agency made the u-turn to subsidise the Synthroid brand of levothyroxine tablets from August 1, which comprises three Times Online - Auckland

Effect of Sample Medication Restrictions on Prescribing at a ...  -  13 Jul 2009
All sampled statins, levothyroxine, and SSRIs were removed from the clinic for 90 days (December 1, 2007–February 28, 2008). No restriction was placed on Archives of Internal Medicine

Once-weekly levothyroxine therapy  -  ‎Jul 1, 2009‎
After not having seen hypothyroidism with persistently elevated thyroid-stimulating hormone levels while on high-dose levothyroxine therapy for several Endocrine Today

Pharmaceutical Update  -  ‎Jun 25, 2009‎
The FDA has approved Unithroid (levothyroxine) by Jerome Stevens Pharmaceuticals for the treatment of hypothyroidism. It is the first drug indicated for ADVANCE for Physician Assistants

BUY CHEAP Synthroid ONLINE  -  ‎Jul 12, 2009‎
Different brands of levothyroxine may not work the same. If you get a prescription refill and your new pills look different, talk with your pharmacist or Cleveland Indy Media

Natural Thyroid Drug Update from RLC Labs -- Maker of Nature ...  -  ‎Jul 9, 2009‎
1 grain of any prescription natural desiccated thyroid drug must, by FDA regulation, contain a guaranteed potency of 38 mcg levothyroxine (T4) and 9 mcg About - News & Issues

Integrative medicine: Alternative approach to thyroid?  -  ‎Jun 22, 2009‎
Standard medical treatment for hypothyroidism is usually synthetic thyroid hormone replacement with a product such as levothyroxine. Deseret News

Forest Pharmaceuticals: Armour Thyroid and Thyrolar are Still Back ...  -  ‎Jul 2, 2009‎
...you can switch to a natural thyroid drug like Nature-throid, or, staying with synthetic medications, change to brand-name levothyroxine (synthetic T4) About - News & Issues

ENDO: Data Support Fasted Dosing of Thyroid Hormone  -  ‎Jun 17, 2009‎
To examine the impact of dosing schedule on serum TSH values, investigators studied 65 patients who were taking levothyroxine for hypothyroidism or thyroid MedPage Today

BiomedReports: Russell Investments' exclusive list adds Insmed ...  -  ‎Jul 1, 2009‎
Of the products, those containing Butalbital, Digoxin, Primidone and Levothyroxine Sodium were the Company's key products, contributing 76% of the Company's Trading Markets (press release)

Merck Serono Launches "Global Fertility Academy" to Provide ...  -  ‎Jul 1, 2009‎
...sapropterin dihydrochloride) as well as cardiometabolic diseases (Glucophage(R), metformin), (Concor(R), bisoprolol), (Euthyrox(R), levothyroxine). SYS-CON Media (press release)

Attention Thyroid Patients: Armour Thyroid Is NOT Off the Market ...  -  ‎Jun 24, 2009‎
Because your pharmacy or doctor may suggest switching to a more easily-obtained synthetic drug, like Synthroid or Levoxyl, or the generic, levothyroxine. About - News & Issues

Symptoms and treatment for underactive thyroid  -  ‎Jun 29, 2009‎
If you are diagnosed with hypothyroidism, you will probably start taking the thyroid hormone medication levothyroxine (Synthroid). Kansas CW

Merck Serono Launches RebiSmart(TM), First Electronic Injection ...  -  ‎Jun 24, 2009‎
...sapropterin dihydrochloride) as wellas cardiometabolic diseases (Glucophage(R), metformin), (Concor(R),bisoprolol), (Euthyrox(R), levothyroxine). Merinews

New Data From CLARITY Study Presented at 19th ENS Meeting Show ...  -  ‎Jun 23, 2009‎
...sapropterin dihydrochloride) as wellas cardiometabolic diseases (Glucophage(R), metformin), (Concor(R),bisoprolol), (Euthyrox(R), levothyroxine). Merinews

Estudio del nódulo tiroideo  -  ‎Jul 12, 2009‎
Suppressive therapy with levothyroxine for solitary thyroid nodules: a prospective randomised trial. World J Surg 1989;13:818-22. Intramed.net (Suscripción)

ED BLONZ ON NUTRITION It's best to take calcium carbonate with meals  -  ‎Apr 16, 2009‎
Finally, calcium supplements can affect the absorption of some medications, including thyroid hormones (levothyroxine), antibiotics (fluoroquinolone and Detroit Free Press

Table Topic: Cushing's or Metabolic Syndrome?  -  ‎Apr 17, 2009‎
Horses with EMS can be treated with levothyroxine sodium to accelerate weight loss, but this treatment should not be used as a substitute for good TheHorse.com

Amisulpride-Induced Tardive Dyskinesia and Possible Association of ...  -  ‎Apr 9, 2009‎
Amisulpride was discontinued and it was replaced by clozapine, which was gradually titrated to 75 mg/day along with levothyroxine, 25 mg/day. Journal of Neuropsychiatry (subscription)

Merck Serono: New Phase III Data for Cladribine Tablets to be ...  -  ‎Mar 30, 2009‎
...endocrine and cardiometabolic disorders (Glucophage(R), metformin); (Concor(R), bisoprolol); (Euthyrox(R), levothyroxine); (Saizen(R) and Serostim(R), FOXBusiness

Grapefruit May Have Raised Blood Clot Risk In Unusual Case  -  ‎Apr 3, 2009‎
...and she was on two types of medication: a low dose contraceptive pill (drospirenone and ethinylestradiol) and a thyroid drug (levothyroxine). Medical News Today

The Thyroid & Pregnancy: ATA Research Summit And Spring Symposium  -  ‎Apr 10, 2009‎
...an average of a 40 percent increase in Levothyroxine is required to cope with the increasing thyroid hormone demand during early pregnancy, Medical News Today (press release)

Грейпфрут вызвал тромбоз глубоких вен  -  ‎Apr 6, 2009‎
жаловалаÑ?ÑŒ на боли в ногах, но принимала противозачаточные таблетки (drospirenone и ethinylestradiol) и лекарÑ?тво длÑ? щитовидной железы (levothyroxine). МЕДСТРИМ.РУ - консультации врачей, новости медицины

Pharmacy Based Repeat Dispensing Can Help People With Long Term ...  -  18 Mar 2009
This NHS service would be ideal for patients on single, stable therapy, for example, Levothyroxine." "The repeat dispensing process removes the need to Medical News Today (press release)

Merck Serono and Fast Forward, LLC Announce Collaboration to ...  -  18 Mar 2009
...endocrine and cardiometabolic disorders (Glucophage(R), metformin); (Concor(R), bisoprolol); (Euthyrox(R), levothyroxine); (Saizen(R) and Serostim(R), ITNews

Dr. John Lowe Issues Scathing Rebuttal of Flawed UK Policy Against ...  -  ‎Mar 16, 2009‎
Dr. Lowe's review of the literature shows that the evidence actually suggests that desiccated thyroid is in fact superior to levothyroxine. About - News & Issues

UK's Controversial Thyroid Guidelines Generate Concern, Outrage ...  -  ‎Feb 26, 2009‎
I cannot tolerate levothyroxine. Why doesn't my GP want me to get better? I just want my life back … please." Jenny says: "This guideline has shocked me to About - News & Issues

Fact Sheet: The Thyroid and Pregnancy  -  ‎Mar 6, 2009‎
Treatment for hypothyroidism during pregnancy is the same as for non-pregnant women – a synthetic form of thyroid hormone called levothyroxine. Newswise (press release)

Wegmans to offer $4 prescription program  -  ‎Feb 25, 2009‎
...medication metformin, cholesterol medications lovastatin and pravastatin, albuterol nebulizers for asthma, and levothyroxine for thyroid conditions. Elmira Star-Gazette

NCCN Presents Updates to NCCN Guidelines for Thyroid Carcinoma  -  ‎Mar 16, 2009‎
Also new to the NCCN Guidelines is a page, Principles of Thyroid Stimulating Hormone (TSH) Suppression that provides recommendations for levothyroxine use PR Newswire (press release)

The People's Pharmacy  -  ‎Mar 2, 2009‎
Many doctors prefer levothyroxine, a synthetic form of the thyroid hormone T4. It is sold under brand names Synthroid and Levoxyl and is also available Seattle Times

Barack Obama and the half used can of moldy Del Monte Tomatoes  -  ‎Mar 11, 2009‎
...aka Thyroxine, such as Synthroid, Levoxyl, Levothyroxine, Unithroid, etc., all which leave patients with lingering hypothyroid symptoms while clueless OpEdNews

EMD Serono Canada Inc.: Health Canada Recommends Suspension of ...  -  ‎Feb 24, 2009‎
...metformin); (Concor®, bisoprolol); (Euthyrox®, levothyroxine); (Saizen® and Serostim®, somatropin). Not all products are available in all markets. MSNBC

Why an Endocrinologist or Thyroidologist Should Probably Not Be ...  -  ‎Mar 8, 2009‎
...which says that keeping the thyroid in balance requires only "three easy steps" -- testing using the TSH test, prescribing levothyroxine so the patient About - News & Issues

Percussion Myotonia  -  ‎Mar 4, 2009‎
The patient had a history of hypercholesterolemia and cataracts and was receiving levothyroxine-replacement therapy after partial thyroidectomy for nodular New England Journal of Medicine (subscription)

A man's temporary vision loss leads to an unexpected diagnosis  -  ‎Mar 3, 2009‎
The patient was currently taking levothyroxine (Synthroid); he was allergic to penicillin. The patient was 5 ft 10 in tall and weighed 214 lb. Clinical Advisor

King Pharmaceuticals Reports Year-End and Fourth-Quarter 2008 ...  -  ‎Feb 26, 2009‎
LEVOXYL(R) (levothyroxine sodium tablets, USP) net sales totaled $20 million during the fourth quarter and $73 million for the year ended December 31, 2008, Trading Markets (press release)

Ambrx and Merck Serono Expand Collaboration Through ARX424 ...  -  ‎Feb 24, 2009‎
...endocrine and cardiometabolic disorders (Glucophage(R), metformin); (Concor(R), bisoprolol); (Euthyrox(R), levothyroxine); (Saizen(R) and Serostim(R), PR Newswire (press release)

Commas, Colons and Other Proofing Peccadilloes  -  ‎Feb 25, 2009‎
...to introduce an example: The patient is currently on the following medications: Prozac 40 mg daily, Norvasc 5 mg daily and levothyroxine 25 mcg daily. ADVANCE

I couldn't work out why I kept piling on weight. Then I was told ...  -  ‎Mar 9, 2009‎
Following her diagnosis with hypothyroidism, Imogen was prescribed levothyroxine (thyroxine) tablets each day to replace the hormones her thyroid gland was Daily Mail

European Medicines Agency Recommends Suspension of Marketing ...  -  ‎Feb 19, 2009‎
...metformin); (Concor®, bisoprolol); (Euthyrox®, levothyroxine); (Saizen® and Serostim®, somatropin). Not all products are available in all markets. PharmaLive.com (press release)

Brand Names/Synonyms:
Levothyroxine is also known by the following brand names and/or synonymsD-Thyroxine; Eltroxin; Euthyrox; Iodine; L-T4; L-THYROXIN SODIUM, 99%; L-Thyroxine; L-Thyroxine Sodium; L-Thyroxine Sodium Salt; L-Thyroxine Sodium Salt Hydrate; L-Thyroxine.Na; Laevothyroxinum; Laevoxin; Letter; Levaxin; Levo-T; Levolet; Levothroid; Levothyrox; Levothyroxine; Levothyroxine Sodium; Levoxine; Levoxyl; Novothyrox; Oroxine; Sodium Levothyroxine; Synthroid; Synthroid Sodium; Tetraiodothyronine; Thyratabs; Thyrax; Thyreoideum; Thyro-Tabs; Thyro-Tapbs; Thyroxevan; Thyroxin; Thyroxinal; Thyroxine; Unithroid

Drug Category:
Levothyroxine is categorized under the following by the FDA: Antithyroid Agents; Anticoagulants; ATC:H03AA01

Dosage Forms:
LIQUID; POWDER; TABLET

Absorption:
Varies from 48% to 80%

Interactions:
-->Interactions for Levothyroxine:

The magnitude and relative importance of the effects noted below are likely to be patient specific and may vary by such factors as age, gender, race, intercurrent illnesses, dose of either agent, additional concomitant medications, and timing of drug administration. Any agent that alters thyroid hormone synthesis, secretion, distribution, effect on target tissues, metabolism, or elimination may alter the optimal therapeutic dose of levothyroxine sodium.

Levothyroxine Sodium Absorption: The following agents may bind and decrease absorption of levothyroxine sodium from the gastrointestinal tract: aluminum hydoxide, cholestyramine resin, colestipol hydrochloride, ferrous sulfate, sodium polystyrene sulfonate, soybean flour (e.g., infant formula), sucralfate.

Binding to Serum Proteins: The following agents may either inhibit levothyroxine sodium binding to serum proteins or alter the concentrations of serum binding proteins: androgens and related anabolic hormones, asparaginase, clofibrate, estrogens and estrogen-containing compounds, 5-fluorouracil, furosemide, glucocorticoids, meclofenamic acid, mefenamic acid, methadone, perphenazine, phenylbutazone, phenytoin, salicylates, tamoxifen.

Thyroid Physiology: The following agents may alter thyroid hormone or TSH levels, generally by effects on thyroid hormone synthesis, secretion, distribution, metabolism, hormone action, or elimination, or altered TSH secretion: aminoglutethimide, p-aminosalicylic acid, amiodarone, androgens and related anabolic hormones, complex anions (thiocyanate, perchlorate, pertechnetate), antithyroid drugs, b-adrenergic blocking agents, carbamazepine, chloral hydrate, diazepam, dopamine and dopamine agonists, ethionamide, glucocorticoids, heparin, hepatic enzyme inducers, insulin, iodinated cholestographic agents, iodine- containing compounds, levodopa, lovastatin, lithium, 6-mercaptopurine, metoclopramide, mitotane, nitroprusside, phenobarbital, phenytoin, resorcinol, rifampin, somatostatin analogs, sulfonamides, sulfonylureas, thiazide diuretics.

Adrenocorticoids: Metabolic clearance of adrenocorticoids is decreased in hypothyroid patients and increased in hyperthyroid patients, and may therefore change with changing thyroid status.

Amiodarone: Amiodarone therapy alone can cause hypothyroidism or hyperthyroidism.

Anticoagulants (Oral): The hypoprothrombinemic effect of anticoagulants may be potentiated, apparently by increased catabloism of vitamin K-dependent clotting factors.

Antidiabetic Agents (Insulin, Sulfonylureas): Requirements for insulin or oral antidiabetic agents may be reduced in hypothyroid patients with diabetes mellitus and may subsequently increase with the initiation of thyroid hormone replacement therapy.

b-Adrenergic Blocking Agents: Actions of some of beta-blocking agents may be impaired when hypothyroid patients become euthyroid.

Cytokines (interferon, interleukin): Cytokines have been reported to induce both hyperthyroidism and hypothyroidism.

Digitalis Glycosides: Therapeutic effects of digitalis glycosides may be reduced. Serum digitalis levels may be decreased in hyperthyroidism or when a hypothyroid patient becomes euthyroid.

Ketamine: Marked hypertension and tachycardia have been reported in association with concomitant administration of levothyroxine sodium and ketamine.

Maprotiline: Risk of cardiac arrhythmias may increase.

Sodium Iodide (123I and 131I), Sodium Pertechnetate Tc99m: Uptake of radiolabeled ions may be decreased.

Somatrem/Somatropin: Excessive concurrent use of thyroid hormone may accelerate epiphyseal closure. Untreated hypothyroidism may interfere with the growth response to somatrem or somatropin.

Theophylline: Theophylline clearance may decrease in hypothyroid patients and return toward normal when a euthyroid state is achieved.

Tricyclic Antidepressants: Concurrent use may increase the therapeutic and toxic effects of both drugs, possibly due to increased catecholamine sensitivity. Onset of action of tricyclics may be accelerated.

Sympathomimetic Agents: Possible increased risk of coronary insufficiency in patients with coronary artery disease.





Chemical IUPAC Name:
2-amino-3-[4-(4-hydroxy-3,5-diiodo-phenoxy)-3,5-diiodo-phenyl]-propanoicacid

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