Chlorprothixene, sold under the brand name Truxal among others, is a typical antipsychotic of the thioxanthene group.

Medical uses

Chlorprothixene's principal indications are the treatment of psychotic disorders (e.g. schizophrenia) and of acute

mania Mania, also known as manic syndrome, is a mental and behavioral disorder defined as a state of abnormally elevated arousal, affect, and energy level, or "a state of heightened overall activation with enhanced affective expression together wit ...

occurring as part of bipolar disorders. Other uses are pre- and postoperative states with anxiety and insomnia, severe nausea / emesis (in hospitalized patients), the amelioration of anxiety and agitation due to use of selective serotonin reuptake inhibitors for depression and, off-label, the amelioration of alcohol and opioid withdrawal. It may also be used cautiously to treat nonpsychotic irritability, aggression, and insomnia in pediatric patients. An intrinsic

antidepressant Antidepressants are a class of medication used to treat major depressive disorder, anxiety disorders, chronic pain conditions, and to help manage addictions. Common side-effects of antidepressants include dry mouth, weight gain, dizziness, hea ...

effect of chlorprothixene has been discussed, but not proven. Likewise, it is unclear if chlorprothixene has genuine (intrinsic)

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

effects. However, chlorprothixene can be used as co-medication in severe chronic pain. Also, like most antipsychotics, chlorprothixene has antiemetic effects.

Side effects

Chlorprothixene has a strong sedative activity with a high incidence of anticholinergic side effects. The types of side effects encountered (dry mouth, massive hypotension and tachycardia, hyperhidrosis, substantial weight gain etc.) normally do not allow a full effective dose for the remission of psychotic disorders to be given. So cotreatment with another, more potent, antipsychotic agent is needed. Chlorprothixene is structurally related to chlorpromazine, with which it shares, in principle, all side effects. Allergic side effects and liver damage seem to appear with an appreciable lower frequency. The elderly are particularly sensitive to anticholinergic side effects of chlorprothixene (precipitation of narrow angle glaucoma, severe obstipation, difficulties in urinating, confusional and delirant states). In patients >60 years the doses should be particularly low. Early and late

extrapyramidal side effects Extrapyramidal symptoms (EPS) are symptoms that are archetypically associated with the extrapyramidal system of the brain's cerebral cortex. When such symptoms are caused by medications or other drugs, they are also known as extrapyramidal side ...

may occur but have been noted with a low frequency (one study with a great number of participants has delivered a total number of only 1%).

Overdose

Overdose symptoms can be confusion, hypotension, and tachycardia, and several fatalities have been reported with concentrations in postmortem blood ranging from 0.1 to 7.0 mg/L compared to non-toxic levels in postmortem blood which can extend to 0.4 mg/kg.

Interactions

Chlorprothixene may increase the plasma-level of concomitantly given lithium. In order to avoid lithium intoxication, lithium plasma levels should be monitored closely. If chlorprothixene is given concomitantly with opioids, the opioid dose should be reduced (by approx. 50%), because chlorprothixene amplifies the therapeutic actions and side effects of opioids considerably. Avoid the concomitant use of chlorprothixene and tramadol (Ultram). Seizures may be encountered with this combination. Consider additive sedative effects and confusional states to emerge, if chlorprothixene is given with

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

s or

barbiturate Barbiturates are a class of depressant drugs that are chemically derived from barbituric acid. They are effective when used medically as anxiolytics, hypnotics, and anticonvulsants, but have physical and psychological addiction potential as we ...

s. Choose particular low doses of these drugs. Exert particular caution in combining chlorprothixene with other anticholinergic drugs (

tricyclic antidepressant Tricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants, which is important for the management of depression. They are second-line drugs next to SSRIs. TCAs were discovered in the early 1950s and we ...

s and antiparkinsonian agents): Particularly the elderly may develop delirium, high fever, severe

obstipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

, even ileus and glaucoma .

Pharmacology

Pharmacodynamics

Chlorprothixene is an

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

of the following receptors: * 5-HT₂, 5-HT₆, 5-HT₇: antipsychotic effects, sedation/anxiolysis, antidepressant effect, weight gain * D₁, D₂, D₃, D₄, D₅: antipsychotic effects, sedation, extrapyramidal side effects, prolactin increase, depression, apathy/anhedonia, weight gain * H₁: sedation, weight gain * Muscarinic acetylcholine receptors: anticholinergic effects, inhibition of extrapyramidal side effects * α₁-Adrenergic: hypotension, sedation, anxiolysis Because of its potent serotonin 5-HT_2A and muscarinic acetylcholine receptor antagonism, chlorprothixene causes relatively mild extrapyramidal symptoms. This is in contrast to most other typical antipsychotics. For this reason, chlorprothixene has sometimes been described instead as an atypical antipsychotic. Chlorprothixene has also been found to act as FIASMA (functional inhibitor of acid sphingomyelinase).

Pharmacokinetics

One metabolite of chlorprothixene is ''N''-desmethylchlorprothixene.

History

Chlorprothixene was the first of the thioxanthene antipsychotics to be synthesized. It was introduced in 1959 by Lundbeck.

Lometraline Lometraline (INN; developmental code name CP-14,368) is a drug and an aminotetralin derivative. A structural modification of tricyclic neuroleptics, lometraline was originally patented by Pfizer as an antipsychotic, tranquilizer, and antiparkins ...

tametraline Tametraline (CP-24,441) is the parent of a series of chemical compounds investigated at Pfizer that eventually led to the development of sertraline (CP-51,974-1). Sertraline has been called "3,4-dichloro-tametraline". This is correct but it is a ...

, and sertraline were reportedly derived via structural modification of chlorprothixene.

Society and culture

Brand names

Chlorprothixene is sold mainly under the brand name Truxal.

Availability

Chlorprothixene is widely available throughout Europe and elsewhere in the world. The drug was previously available in the United States under the brand name Taractan, but this formulation has since been discontinued and the drug is no longer available in this country.

References

{{Authority control 5-HT2A antagonists 5-HT6 antagonists 5-HT7 antagonists Alpha-1 blockers Dimethylamino compounds Antihistamines Chloroarenes D1 antagonists D2 antagonists D3 antagonists D4 antagonists D5 antagonists H1 receptor antagonists Muscarinic antagonists Thioxanthene antipsychotics