Antipsychotics are drugs used to treat psychosis, delirium, Obsessive-Compulsive Disorder (severe), agitation and violent behaviour, among others. In psychiatry, mental health and primary care, their use is widespread.

In this article we will talk about moperone, an antipsychotic of the butyrophenone group . It is a highly potent drug (it has a great affinity with the receptors on which it acts) and of low toxicity (very safe).

Moperona: what is it and what is it for?

Moperone is a first generation antipsychotic drug, which is marketed as Luvatren . This drug is originally from Japan, belongs to the butyrophenone group and is used primarily to treat schizophrenia as well as other psychotic disorders or those with psychotic symptoms.

It is a high-powered antipsychotic, that is, it has a great affinity for binding with its receptor and exerting its effect. At a biochemical level and as a mechanism of action, the affinity of moperone is greater for the dopamine D2 receptors , which are closely related to schizophrenia (where there is an excess of this substance). It also has affinity for the 5-HT2 serotonin receptors, although to a lesser degree, and for the sigma receptors.

Its effects

Moperone acts by inhibiting aggression and reducing psychotic symptoms . At the chemical level it does so through an antagonistic effect on apomorphine, adrenaline and noradrenaline.

Another effect is that it increases plasma and adrenal concentrations of adrenal corticosterone.

Dopamine and its presence in the brain

As we have seen, moperone acts, among others, on the D2 receptors of dopamine. But… what else do we know about this substance, dopamine, which is so closely related to psychosis?

Dopamine is a brain neurotransmitter that has various locations and functions : it is found in the nigrostriatal system, in the mesolimbic system, in the mesocortical system and in the tuberoinfundibular system. In the nigrostriatum it is related to movement, in the mesolimbic system to reinforcement and emotion, in the mesocortical system to executive functions and in the tuberoinfundibular system to inhibition of prolactin.

Its receptors, besides being D2, are also D1 and D5 (post-synaptic receptors). The D2, along with D3 and D4, can be both pre and post-synaptic. The D2 receptors are altered in schizophrenia (by excess). These receptors are involved in reinforcement and addictions.

Antipsychotics

Moperone is a type of antipsychotic; antipsychotics generally act by blocking D2 (dopamine) receptors.

As for their indications, are mainly used for psychosis, confusion and delirium, agitation and violent behaviour , movement disorders (tics, Gilles de Tourette,…), severe OCD (Obsessive-Compulsive Disorder), alcohol deprivation and chronic pain.

In addition to these indications, second generation (atypical) antipsychotics are also used for bipolar disorder, borderline personality disorder and autism.

On the other hand, improves the positive symptoms of schizophrenia (hallucinations, delusions, disorganized behaviour,..). The second generation also improves the negative symptoms (apathy, abulia, depression…) although to a lesser extent.

Butyrophenones

As we have seen, moperone belongs to the butyrophenones, a group of neuroleptic drugs (antipsychotics); the best known and most used of this group is haloperidol, a classic antipsychotic (first generation). So is, but not so much, droperidol.

Pharmacologically and clinically, butyrophenones are similar to phenothiazines, chemical intermediates in the synthesis of antipsychotic drugs.

As for the effects of butyrophenones, in addition to mitigating psychotic symptoms, in some cases they also reduce the Korean symptoms of Huntington’s chorea , as well as the tics and coprolalia (uttering insults and swear words) typical of Gilles de la Tourette syndrome.

Side effects of this drug

The main side effects of moperone are extrapyramidal motor symptoms, thirst and insomnia .

Extrapyramidal motor symptoms (also called SEP, extrapyramidal syndrome), encompass a range of symptoms such as tardive dyskinesia, akathisia, dystonia and parkinsonism. These motor symptoms are common side effects of antipsychotics such as moperone, along with others such as the antihistamine effect (producing sedation and weight gain), the anticholinergic effect (produced by a muscle block) and cardiovascular effects (produced by blocking the alpha1 receptor).

However, even though it has certain side effects, moperone has a low toxicity ; this means that it takes high doses to become intoxicated or cause serious harm, making it a fairly safe substance.

Pregnancy and lactation

Like many other drugs, moperone requires special use when pregnant and/or breastfeeding .

In pregnancy, extrapyramidal and withdrawal symptoms, respiratory disorders, tremors, sleepiness, feeding disorders, as well as irritability and hypotonia have been detected in infants whose mothers took antipsychotics (such as moperone) at the end of their pregnancy.

As far as breastfeeding is concerned, moperone passes into breast milk, as do other antipsychotics such as haloperidol. This is why its use is not recommended in the breastfeeding stages .

Bibliographic references:

  • Aimoto, T; Kaida, M; Sato, M; Sato, M; Kimura, R; Murata, T. (1980). Effects of neuroleptic butyrophenones on pituitary-adrenal activity in rats. Journal of pharmacobio-dynamics 3(1): 46-52.
  • Janicaz, P.G. (1999) Handbook of Psychopharmacotherapy. Philadelphia: Lippincott Williams & Wilkins.
  • Stahl, S.M. (2002). Essential Psychopharmacology. Neuroscientific bases and clinical applications. Barcelona: Ariel.
  • Stolerman, I. (2010). Encyclopedia of Psychopharmacology. (Online-Ausg. edition). Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 798.