Chlorpromazine: effects and uses of this psychoactive drug

In ancient times, schizophrenia and psychotic disorders had a treatment that made it possible to combat the different symptoms and perceptual and cognitive alterations.

This would change with the discovery of the first antipsychotics, making it possible for the first time for patients with these disorders to receive outpatient treatment without requiring hospitalization. One of the first and best known is chlorpromazine.

• Related article: "Types of antipsychotics (or neuroleptics)"

Chlorpromazine: description and a little history

Chlorpromazine is a substance belonging to the group of antipsychotics or neuroleptics, which have a great effect in controlling psychotic symptoms such as hallucinations, agitation and delusion.

It is one of the first antipsychotics, and is part of the group of classic or typical neuroleptics. Structurally it is a phenothiazine. Although it is true that although chlorpromazine continues to be used today in the treatment of psychopathologies such as schizophrenia, it is usually The use of other types of antipsychotics should be preferred due to the risks and side effects that the classic ones can generate, at the time they were all a revolution and served (and continues to serve in many cases) to greatly improve the quality of life of patients with various disorders mental.

This substance was discovered and synthesized by chance by Paul Charpentier in 1950 while searching for a remedy against malaria. However, some time later Henri Laborit, after observing its calming effects without necessarily causing sedation in the affected person, would begin to recommend and establish its use in psychiatry. It would be used for the first time in the treatment of psychotic-type psychopathologies in 1951, with notable success that would lead to the discovery being called the fourth revolution in psychiatry.

And it is that previously the methods used to treat psychotic patients were generally ineffective, risky and highly aversive and painful for the patient (for example, inducing insulin coma or the use of electroshock). The fact that chlorpromazine was effective allowed a more biologist view of psychotic disorders and it would begin to allow outpatient treatment instead of requiring hospitalization in most cases.

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Mechanism of action

As we have mentioned, chlorpromazine is one of the classic or typical antipsychotics. These types of antipsychotics act by blocking the receptors of dopamine in the brain, especially the D2 receptor.

The fact that this block is beneficial is due to the fact that in schizophrenia, positive symptoms such as hallucinations, disturbances of thought and language, distractibility, agitation, and restlessness tend to be due to the presence of excess dopamine in the pathway mesolimbic. By blocking its emission, there is a great improvement in psychotic symptoms. of this type.

However, both chlorpromazine and the rest of the classic antipsychotics affect dopamine receptors non-specifically, that is, throughout the brain. In this way, not only the pathway that presents an excess of dopamine is affected, but also other pathways that had adequate or even low levels, their levels of this neurotransmitter were excessively decreased. It also has an effect on acetylcholine and other neurotransmitters. This causes the appearance of secondary symptoms of variable severity.

In addition, in schizophrenia other symptoms also appear in which there is a flattening, slowing down or reduction of functions and processes, especially at the cognitive level. The most classic example of these symptoms (called negatives) is the alogia or poverty of thought. these symptoms are linked to a dopaminergic deficit in the mesocortical pathway, so that the effect of chlorpromazine is not only not positive in these symptoms, but it could also cause some worsening.

• Related article: "The 6 types of schizophrenia and associated features"

Chlorpromazine Side Effects and Risks

As with other psychotropic drugs, the use of chlorpromazine can have a series of side effects and risks to take into consideration. As we have mentioned before, by exerting an antagonistic effect on dopamine in all pathways, it is possible that problems arise from it.

One of the main problems derived from the decrease in dopamine, specifically when it occurs in the nigrostriatal pathway, is the appearance of motor disorders such as slowness, akathisia, dystonia, rigidity and tremors both by themselves and in what comes to be called parkinsonian syndrome. Another of the frequent symptoms is tardive dyskinesia or emission of repetitive and involuntary movements of the face and sometimes of the trunk and extremities.

In the tuberoinfundibular pathway, dopamine blockade can cause the presence of alterations such as galactorrhea or emission of milk from the breasts (regardless of sex), gynecomastia or breast growth (also in both sexes) and changes in sexual response.

It has also been commented that chlorpromazine and other typical antipsychotics they can produce side effects derived from their interaction with acetylcholine. Among them we find mental dullness, constipation, blurred vision or ocular hypertension.

Other frequently reported side effects are a high level of sedation and a noticeable weight gain, having to be careful in cases of eating or metabolic problems. It can also cause problems such as high blood pressure or dizziness, having effects on the cardiovascular system.

Lastly, one of the most serious syndromes and one that can culminate in the death of the patient (although it is very rare) is the neuroleptic malignant syndrome, in which fever, cyanosis, tachycardia and in some cases coma and even death appear. It is to prevent this syndrome and other problems for which the dosage of this type of substance is carried out with extreme care.

Situations and disorders for which it is indicated

One of the most widespread uses of chlorpromazine is even today (although there is a preference for the use of atypical neuroleptics such as olanzapine due to their greater safety and their effects on symptoms negative) treatment of schizophrenia and other psychotic disorders.

However, chlorpromazine has also been shown to be effective in treating manic states. In general, it is effective in all those situations in which positive psychotic symptoms or states of intense motor agitation are present. This includes the presence of delirium and in some withdrawal syndromes. It has been used successfully in reduce choreic symptoms in Huntington's chorea, and sometimes it can be used as the last option in cases of OCD.

At a more physiological level, we observe that it is sometimes used to treat intestinal problems such as nausea and vomiting (since it is antiemetic), tetanus or porphyria.

Likewise, given its calming potential, it has also sometimes been used in situations in which there are problems with sleep (not in vain, at first antipsychotics were called tranquilizers greater). Also in situations that present with high pain.

Bibliographic references:

• Gomez, M. (2012). Psychobiology. CEDE Preparation Manual PIR.12. CEDE: Madrid.

• Mazana, J.S.; Pereira, J. and Cabrera, R. (2002). Fifty years of chlorpromazine. Spanish Journal of Prison Health, vol.4 (3). CP Tenerife II. Medical services.

• Salazar, M.; Peralta, C.; Shepherd, J. (2006). Manual of Psychopharmacology. Madrid, Panamerican Medical Editorial.