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Propylthiouracil
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| Systematic (IUPAC) name | |
| 6-propyl-2-sulfanyl-pyrimidin-4-ol | |
| Identifiers | |
| CAS number | |
| ATC code | H03 |
| PubChem | |
| DrugBank | |
| Chemical data | |
| Formula | C7H10N2OS |
| Mol. mass | 170. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to The Anatomical Therapeutic Chemical Classification System is used for the classification of drugs It is controlled by the WHO Collaborating Centre for Drug A section of the Anatomical Therapeutic Chemical Classification System. PubChem is a Database of chemical Molecules The system is maintained by the National Center for Biotechnology Information (NCBI a component The DrugBank database available at the University of Alberta is a unique Bioinformatics and Cheminformatics resource that combines detailed drug (i A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one 233 g/mol |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Metabolism | ? |
| Half life | 2 hours |
| Excretion | ? |
| Therapeutic considerations | |
| Pregnancy cat. |
? |
| Legal status |
? |
| Routes | Oral |
Propylthiouracil (PTU) or 6-N-Propylthiouracil (PROP) is a thioamide drug used to treat hyperthyroidism by decreasing the amount of thyroid hormone produced by the thyroid gland. In Pharmacology, bioavailability is used to describe the fraction of an administered Dose of unchanged drug that reaches the Systemic circulation, one of Drug metabolism is the Metabolism of drugs, their Biochemical modification or degradation usually through specialized enzymatic systems The biological half-life of a substance is the time it takes for a substance (drug radioactive nuclide or other to lose half of its pharmacologic physiologic or radiologic activity Excretion is the process of eliminating waste products of Metabolism and other non-useful materials The pregnancy category of a pharmaceutical agent is an assessment of the risk of fetal injury due to the pharmaceutical if it is used as directed by the mother during The regulation of therapeutic goods, that is drugs and therapeutic devices, varies by jurisdiction In Pharmacology and Toxicology, a route Thioamide (rarely thionamide) is a Functional group with the general structure R-CS-NR'R, where R R' and R are organic groups Hyperthyroidism is the term for overactive tissue within the Thyroid gland resulting in overproduction and thus an excess of circulating free thyroid hormones Thyroxine The thyroid hormones, Thyroxine ( T4) and Triiodothyronine ( T3) are Tyrosine -based Hormones produced The thyroid is one of the largest Endocrine glands in the body It was approved by the United States Food and Drug Administration in 1947. The United States of America —commonly referred to as the Year 1947 ( MCMXLVII) was a Common year starting on Wednesday (link will display full 1947 calendar of the Gregorian calendar. It is used to study the genetics of bitter perception with supertaster. A supertaster is a person who experiences Taste with far greater intensity than average [1]
Contents |
Indications
Hyperthyroidism, including Graves disease. Graves' disease is a Thyroid disorder characterized by goiter, Exophthalmos, "orange-peel" skin and Hyperthyroidism.
Mode of action
PTU inhibits the enzyme thyroperoxidase, which normally acts in thyroid hormone synthesis to add iodide to the tyrosine residues on the hormone precursor thyroglobulin, thus forming thyroxine. Thyroid peroxidase or Thyroperoxidase (TPO is an Enzyme mainly expressed in the Thyroid that liberates Iodine for addition onto Tyrosine An iodide Ion is an iodine atom with a &minus1 charge. Compounds with iodine in formal Oxidation state &minus1 are called iodides Thyroglobulin (Tg is a 660 kDa dimeric Protein produced by and used entirely within the Thyroid gland Thyroxine, or 353'5'-tetraiodothyronine (often abbreviated as T4) a form of Thyroid hormones is the major Hormone secreted by the PTU also acts by inhibiting the enzyme 5'-deiodinase (tetraiodothyronine 5' deiodinase), which converts T4 to the active form T3. Tetraiodothyronine 5' deiodinase is an Enzyme. The Amino acid Selenocysteine is one of its Constituent parts Notably, PTU does not inhibit the action of the sodium-dependent iodide transporter located on follicular cells' basolateral membranes. Inhibition of this step requires competitive inhibitors such as perchlorate and thiocyanate. Perchlorates are the salts derived from Perchloric acid ( H[[chlorine Cl]] O4) Thiocyanate (also known as sulphocyanate or thiocyanide or rhodanide) is the anion −
Pharmacokinetics
Administration is oral with peak serum concentrations occurring in one hour, and actively concentrated to the thyroid gland. Depending on several patient variables, however, euthyroid status may not be achieved until 2–4 months after treatment initiation. Of note, the drug is approximately 70% protein-bound and significantly ionized at normal physiologic pH. As a result, there is little placental transfer or distribution to breast milk. In contrast, the antithyroid agent methimazole has higher levels of both placental transfer and breast milk distribution and is therefore contraindicated in pregnant/lactating females. Methimazole (also known as Tapazole) is an antithyroid drug similar in action to Propylthiouracil, and part of the Thioamide
The plasma half-life is one hour and is not altered appreciably by the thyroid status of the patient. Due to the concentration in the thyroid, however, dosing intervals may last 8 hours or longer. Less than 10% of the drug is excreted unchanged, the remaining fraction undergoing extensive hepatic metabolism via glucuronidation. Glucuronic acid (from Greek γλυκερός - "sweet" is a Carboxylic acid.
Side effects
Agranulocytosis- a decrease of white blood cells in the blood. Agranulocytosis is an acute condition involving a severe and dangerous Leukopenia particularly of neutrophils causing a Neutropenia in the circulating blood Symptoms and signs of agranulocytosis include infectious lesions of the throat, the gastrointestinal tract and skin with an overall feeling of illness and fever. A decrease in blood platelets (thrombocytopenia) also may occur. Since platelets are important for the clotting of blood, thrombocytopenia may lead to problems with excessive bleeding.
Propylthiouracil (PTU) is generally well-tolerated with side effects occurring in 1 of every 100 patients. The most common side effects are related to the skin and include rash, itching, hives, abnormal hair loss, and skin pigmentation. Other common side effects are swelling, nausea, vomiting, heartburn, loss of taste, joint or muscle aches, numbness and headache, allergic reactions, and hair whitening.
Propylthiouracil in Pregnancy
Propylthiouracil is classified as Drug Class D in pregnancy. Class D signifies that there is positive evidence of human fetal risk. Maternal benefit may outweigh fetal risk in life-threatening situations. [2]
The primary effect on the fetus from transplacental passage of PTU is the production of a mild hypothyroidism when the drug is used close to term. This usually resolves within a few days without treatment. Clinically, the hypothyroid state may be observed as a goiter in the newborn and is the result of increased levels of fetal pituitary thyrotropin. The incidence of fetal goiter after PTU treatment in reported cases is approximately 12%. [3]
References
- ^ Duffy, V. B. , Davidson, A. C. , Kidd, J. R. , Kidd, K. K. , Speed, W. C. , Pakstis, A. J. , Reed, D. R. , Snyder, D. J. and Bartoshuk, L. M. (2004) Bitter receptor gene (TAS2R38), 6-n-propylthiouracil (PROP) bitterness and alcohol intake. Alcohol Clin Exp Res, 28, 1629-1637.
- ^ propylthiouracil
- ^ Propylthiouracil: Drug safety during pregnancy and breastfeeding / DRUGSAFETYSITE.COM
- Clinical Pharmacology Online Database. Retrieved on 2007-04-02. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 68 - Galba, Governor of Hispania, names himself legatus senatus populique Romani, breaking the line of
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