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
KEGG Compound
C08212
PubChem Compound
23666112
ChemSpider
8051352
ChEBI
6446
Wikipedia
Levothyroxine
Predicted Properties
PropertyValueSource
Water Solubility0.00475 mg/mLALOGPS
logP1.31ALOGPS
logP3.73Chemaxon
logS-5.2ALOGPS
pKa (Strongest Acidic)0.27Chemaxon
pKa (Strongest Basic)9.43Chemaxon
Physiological Charge0Chemaxon
Hydrogen Acceptor Count4Chemaxon
Hydrogen Donor Count2Chemaxon
Polar Surface Area95.61 Å2Chemaxon
Rotatable Bond Count5Chemaxon
Refractivity137.34 m3·mol-1Chemaxon
Polarizability49 Å3Chemaxon
Number of Rings2Chemaxon
Bioavailability1Chemaxon
Rule of FiveNoChemaxon
Ghose FilterNoChemaxon
Veber's RuleNoChemaxon
MDDR-like RuleNoChemaxon