Levothyroxine sodiumProduct ingredient for Levothyroxine
- Name
- Levothyroxine sodium
- Drug Entry
- Levothyroxine
Levothyroxine is a synthetically produced form of thyroxine, a major endogenous hormone secreted by the thyroid gland.15 Also known as L-thyroxine or the brand name product Synthroid, levothyroxine is used primarily to treat hypothyroidism, a condition where the thyroid gland is no longer able to produce sufficient quantities of the thyroid hormones T4 (tetraiodothyronine or thyroxine) and T3 (triiodothyronine or Liothyronine), resulting in diminished down-stream effects of these hormones. Without sufficient quantities of circulating thyroid hormones, symptoms of hypothyroidism begin to develop such as fatigue, increased heart rate, depression4, dry skin and hair, muscle cramps, constipation, weight gain, memory impairment, and poor tolerance to cold temperatures.16,10
In response to Thyroid Stimulating Hormone (TSH) release by the pituitary gland, a normally functioning thyroid gland will produce and secrete T4, which is then converted through deiodination (by type I or type II 5′-deiodinases)8 into its active metabolite T3. While T4 is the major product secreted by the thyroid gland, T3 exerts the majority of the physiological effects of the thyroid hormones; T4 and T3 have a relative potency of ~1:4 (T4:T3).15 T4 and T3 act on nearly every cell of the body, but have a particularly strong effect on the cardiac system.6 As a result, many cardiac functions including heart rate, cardiac output, and systemic vascular resistance are closely linked to thyroid status.7
Prior to the development of levothyroxine, Thyroid, porcine or desiccated thyroid, used to be the mainstay of treatment for hypothyroidism. However, this is no longer recommended for the majority of patients due to several clinical concerns including limited controlled trials supporting its use. Desiccated thyroid products contain a ratio of T4 to T3 of 4.2:1, which is significantly lower than the 14:1 ratio of secretion by the human thyroid gland. This higher proportion of T3 in desiccated thyroid products can lead to supraphysiologic levels of T3 which may put patients at risk of thyrotoxicosis if thyroid extract therapy is not adjusted according to the serum TSH.10,16
- Accession Number
- DBSALT000244
- Structure
- Synonyms
- Levothyroxine sodium anhydrous
- UNII
- 054I36CPMN
- CAS Number
- 55-03-8
- Weight
- Average: 798.8518
Monoisotopic: 798.668626168 - Chemical Formula
- C15H10I4NNaO4
- InChI Key
- YDTFRJLNMPSCFM-UHFFFAOYSA-M
- InChI
- InChI=1S/C15H11I4NO4.Na/c16-8-4-7(5-9(17)13(8)21)24-14-10(18)1-6(2-11(14)19)3-12(20)15(22)23;/h1-2,4-5,12,21H,3,20H2,(H,22,23);/q;+1/p-1
- IUPAC Name
- sodium 4-{4-[(2S)-2-amino-2-carboxyethyl]-2,6-diiodophenoxy}-2,6-diiodobenzen-1-olate
- SMILES
- [Na+].[H][C@](N)(CC1=CC(I)=C(OC2=CC(I)=C([O-])C(I)=C2)C(I)=C1)C(O)=O
- External Links
- KEGG Compound
- C08212
- PubChem Compound
- 23666112
- ChemSpider
- 8051352
- ChEBI
- 6446
- Wikipedia
- Levothyroxine
- Predicted Properties
Property Value Source Water Solubility 0.00475 mg/mL ALOGPS logP 1.31 ALOGPS logP 3.73 Chemaxon logS -5.2 ALOGPS pKa (Strongest Acidic) 0.27 Chemaxon pKa (Strongest Basic) 9.43 Chemaxon Physiological Charge 0 Chemaxon Hydrogen Acceptor Count 4 Chemaxon Hydrogen Donor Count 2 Chemaxon Polar Surface Area 95.61 Å2 Chemaxon Rotatable Bond Count 5 Chemaxon Refractivity 137.34 m3·mol-1 Chemaxon Polarizability 49 Å3 Chemaxon Number of Rings 2 Chemaxon Bioavailability 1 Chemaxon Rule of Five No Chemaxon Ghose Filter No Chemaxon Veber's Rule No Chemaxon MDDR-like Rule No Chemaxon