Thioxanthene
Encyclopedia
Thioxanthene is a chemical compound
in which the oxygen
atom in xanthene
is replaced with a sulfur
atom. It is also related to phenothiazine
. Several of its derivatives are used as typical antipsychotic
s in the treatment of schizophrenia
and other psychose
s.
The therapeutic efficacy of these drugs is related to their ability to antagonize
the D2 receptors in the brain, though they have actions at other sites such as serotonin, adrenaline
, and histamine receptor
s as well which mostly contribute to side effect
s.
The thioxanthenes, as a class, are closely related chemically to the phenothiazines. The major structural difference is that the nitrogen at position 10 in the phenothiazines is replaced by a carbon atom with a double bond to the side chain. This difference is noted in the illustration of flupenthixol, which shows a double bonded carbon in the number 10 position (opposite the sulfur molecule in the central chain).
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
in which the oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
atom in xanthene
Xanthene
Xanthene is a yellow organic heterocyclic compound. Its chemical formula is 1310. It is soluble in diethyl ether. Its melting point is 101-102 °C and its boiling point is 310-312 °C...
is replaced with a sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
atom. It is also related to phenothiazine
Phenothiazine
Phenothiazine is an organic compound that occurs in various antipsychotic and antihistaminic drugs. It has the formula S2NH. This yellow tricyclic compound is soluble in acetic acid, benzene, and ether. The compound is related to the thiazine-class of heterocyclic compounds...
. Several of its derivatives are used as typical antipsychotic
Typical antipsychotic
Typical antipsychotics are a class of antipsychotic drugs first developed in the 1950s and used to treat psychosis...
s in the treatment of schizophrenia
Schizophrenia
Schizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
and other psychose
Psychosis
Psychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
s.
Derivatives
The derivatives of thioxanthene used clinically as antipsychotics include:- ChlorprothixeneChlorprothixeneChlorprothixene is a typical antipsychotic drug of the thioxanthene class and was the first of the series to be synthesized...
(Cloxan, Taractan, Truxal) - ClopenthixolClopenthixolClopenthixol , also known as clopentixol, is a typical antipsychotic drug of the thioxanthene class. It was introduced by Lundbeck in 1961....
(Sordinol) - Flupenthixol (Depixol, Fluanxol)
- ThiothixeneThiothixeneThiothixene is a typical antipsychotic drug of the thioxanthene class used in the treatment of psychoses like schizophrenia. It was introduced on July 24, 1967 by Pfizer.-Chemistry:*Bloom, B. M.; Muren, J. F.; 1967, See also:...
(Navane) - ZuclopenthixolZuclopenthixolZuclopenthixol , also known as zuclopentixol, is a typical antipsychotic drug of the thioxanthene class...
(Cisordinol, Clopixol, Acuphase)
The therapeutic efficacy of these drugs is related to their ability to antagonize
Receptor antagonist
A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
the D2 receptors in the brain, though they have actions at other sites such as serotonin, adrenaline
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
, and histamine receptor
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...
s as well which mostly contribute to side effect
Side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequences of the use of a drug.Occasionally, drugs are...
s.
The thioxanthenes, as a class, are closely related chemically to the phenothiazines. The major structural difference is that the nitrogen at position 10 in the phenothiazines is replaced by a carbon atom with a double bond to the side chain. This difference is noted in the illustration of flupenthixol, which shows a double bonded carbon in the number 10 position (opposite the sulfur molecule in the central chain).