The Medicines for schizophrenia Used mainly for their treatment are antipsychotic or neuroleptic drugs. Like all Psychotropic drugs , When ingested, antipsychotics produce specific modifications in the brain. In particular, they often act on the Dopamine , the Serotonin and the Histamine .
The main chemical activity of Antipsychotics Lies in blocking the receptors of different neurotransmitters. In this way, they allow to reduce the level of cerebral excitation.
This factor explains the efficacy of these drugs in the reduction of symptoms typical of psychosis Such as delusions and Hallucinations . By reducing the amount of active neurotransmitters in the brain, the positive symptomatology is reduced.
However, not all types of antipsychotics have the same characteristics or effect on the brain.
Specifically, we now find two major types of neuroleptics: typical antipsychotics and atypical antipsychotics.
Typical antipsychotics
Typical antipsychotics, also known as first generation antipsychotics or conventional antipsychotics, are a class of neuroleptic drugs that developed in the middle of the last century.
They were designed for the treatment of psychoses, especially of the schizophrenia , Although they may also be suitable drugs for intervening manic episodes, agitation or other type of Emotional alterations .
Within classical antipsychotics, two types of drugs can be distinguished: low potency neuroleptics and high potential neuroleptics.
The first group consists of chlorpromazine, promethazine, thyroxine and levomepromazine. The second includes fluefenazine, haloperidol, trifluoperazine and pimozide.
The mechanism of action of these drugs is based on four different pathways: the mesocortical pathway, the mesolimbic pathway, the nigrostriatal pathway and the tuberoinfundibular pathway.
A) Mesocortical pathway
The mesocortical pathway is associated with neurocognitive symptoms and disorders in the modulation of emotions and affectivity. Classical antipsychotics block this pathway, so that their use may cause negative effects such as apathy , Affective flattening or Neurocognitive impairment .
B) Mesolimbic way
The mesolimbic pathway is involved in the pathophysiology of the positive symptoms (delusions and hallucinations) of schizophrenia.
Classical antipsychotics block dopamine receptors, which reduce the excess of this substance at the brain level, and reduce psychotic symptoms.
C) nigroestriada route
Classical antipsychotics block dopamine (D2) receptors in the nigrostriatal pathway. This factor is strongly associated with an increased risk of experiencing extrapyramidal symptoms such as Muscle stiffness , Lack of balance or loss of control in movements.
D) Tuberoinfundibular pathway
Dopamine acts as a prolactin inhibitory factor. Thus, blocking the D2 receptors that make the typical antipsychotics facilitate their release in the pituitary gland .
Types of typical antipsychotics
Due to the side effects of classical antipsychotics and to the fact that these are only used to treat the positive symptoms of schizophrenia (and not the negative ones), the use of these drugs has been clearly superseded by atypical antipsychotics.
However, these drugs continue to be used today. In fact, eight different types of classical antipsychotic drugs are available on the market. These are:
1- Fluphenazine
Fluphenazine is an antipsychotic drug that comes in the form of tablets or liquid for oral administration. Usually taken two or three times a day.
It is a drug little used today because of its side effects. The main ones are: upset stomach, drowsiness, weakness or tiredness, anxiety , insomnia , nightmares , Dry mouth, sun-sensitive skin, and appetite disturbances.
2- Trifluoperazine
This medicine comes in the form of tablets and is usually taken once or twice a day. It is used primarily to treat the symptoms of schizophrenia and occasionally to intervene Anxiety episodes .
Side effects of this drug are also numerous. Its consumption can cause drowsiness, Dizziness , blurry vision , Dry mouth, nasal congestion, nausea, difficulty urinating, constipation , Changes in appetite, difficulty sleeping, Headaches , Weakness or exhausted among others.
3-Mesoridazine
Mesoridazine is used for the treatment of schizophrenia, agitation, anxiety, tension, Hyperactivity And lack of cooperation. It can be consumed as much by tablets as in liquid form.
The liquid concentrate should be diluted before being consumed. Also, due to stomach upset caused by the drug, it is usually recommended to take it with food or milk.
Consumption can cause drowsiness, vomiting, diarrhea, constipation, headache, weight gain and agitation.
4- Chlorpromazine
It is a classic low-potency antipsychotic, and was one of the most widely used drugs in the treatment of symptoms of schizophrenia during the last century.
Nowadays, its consumption is much reduced due to its side effects and the low efficacy that it presents to intervene the negative symptoms of the disease.
However, several people with schizophrenia continue to be treated with chlorpromazine today.
5-Thioridazine
It is another low potency antipsychotic drug. It has been used for many years as a treatment of the positive symptoms of schizophrenia.
However, this medication can cause a serious type of irregular heartbeat. Fact that can even cause sudden death.
For this reason, its use as an antipsychotic drug is now discouraged, as there are other effective drugs that have fewer risk factors.
6- Haloperidol
Haloperidol is the best-known classical antipsychotic drug, and the drug that has been used most abundantly for the treatment of schizophrenia.
In fact, until the onset of atypical antipsychotics, haloperidol was the main drug for the treatment of psychotic disorders.
It can be taken either through tablets or by injection, and acts to decrease the abnormal excitation of the brain. Apart from schizophrenia, it is also used to treat serious behavioral problems, such as Aggressive and explosive behavior Or hyperactivity.
It is one of the most potent antipsychotics but its consumption can cause side effects such as blurred vision, loss of appetite, constipation, heartburn, lack of expression on the face, uncontrollable eye movements, mood swings or Decreased sexual ability .
7-Thiothixene
Thiothixene is in the form of capsules. It is used to treat symptoms of schizophrenia, but unlike other drugs, the Food and Drug Administration (FDA) has not authorized its use for the treatment of behavioral problems.
Also, this medication is not recommended as a treatment in people with Dementia syndromes , Since it increases the probability of death.
8-Molindone
This drug has high similarities with thiothixene. It is used to treat symptoms of schizophrenia but is not advised to intervene in behavioral changes and dementia syndromes.
Also, the use of molindone is noticeably limited today because of its side effects.
Drowsiness, increased salivation, Difficulty urinating , Lack of expression on the face, depression, changes in menstruation and sexual desire, and decreased ability to walk are the most important.
9- Loxapine
Finally, loxapine is a typical antipsychotic that was previously used to treat the positive symptoms of schizophrenia.
However, the long list of side effects caused by its use, and the lack of effectiveness in treating the negative symptoms of the disease, mean that this medication is practically not used today.
Atypical antipsychotics
Atypical or new generation antipsychotics are antipsychotic medications that have certain differences from typical ones. These differences make them better therapeutic options for the treatment of schizophrenia. The main ones are:
Atypical antipsychotics, unlike typical ones, specifically inhibit D2 receptors. Thus, they have a lower propensity to produce extrapyramidal symptoms.
Atypical antipsychotics have the advantage of not producing an increase in prolactin secretion, a fact that is present with the administration of conventional antipsychotics.
Atypical antipsychotics, unlike typical ones, also block serotonin receptors. For this reason, they are more effective in controlling the negative symptoms of schizophrenia.
It has been shown that novel antipsychotics may be effective in patients who do not respond correctly to treatment with conventional antipsychotics.
For this reason, these drugs are the most commonly used drugs today. Both to intervene the symptoms of schizophrenia (positive and negative) and to treat episodes of anxiety, agitation or hyperactivity.
Types of atypical antipsychotics
The efficacy of these drugs in the treatment of the two types of symptoms of schizophrenia has led to a clear preference for atypical antipsychotics versus classical antipsychotics.
Also, the reduction of extrapyramidal effects, one of the main disadvantages of antipsychotics, has also contributed to increase scientific interest in these drugs.
In this sense, research on atypical antipsychotics is on the rise, these drugs are increasingly being used and today they are vital for schizophrenia intervention.
At present, there are five main types of atypical antipsychotics that are used very frequently. These are:
10-Clozapine
Clozapine was the first atypical antipsychotic drug to be developed. In fact, its design revealed the efficacy of the mechanism of action and the effects of this type of drugs, which uncovered the interest in these new antipsychotics.
It was created in the late 50's of the previous century and its main features were: low rate of extrapyramidal neurological adverse effects and greater efficacy compared to typical antipsychotics in the treatment of schizophrenia.
However, clozapine also has significant adverse effects. Its consumption can cause a strong sedation, increase of weight, decrease of the blood pressure and increase of triglycerides in the blood.
Thus, clozapine is now a second-choice drug because of its toxicity and side effects.
Its main indications are the treatment of subjects with schizophrenia who do not respond to other atypical antipsychotics, and individuals with schizophrenia who present with severe extrapyramidal symptoms.
Aside from schizophrenia, it can also be used for the treatment of delusional disorders, Severe manic and depressive episodes , And diseases such as Parkinson's and the Dementia by Lewy Bodies Which occur with delusions or hallucinations.
11- Risperidone
Risperidone is another of the currently used atypical antipsychotics. It is sold commercially as Risperdal and is frequently used as a treatment for schizophrenia.
Likewise, the Food and Drug Administration (FDA) has also authorized its use to intervene in the Bipolar disorder , the Autistic disorders , the panic attacks , he Obsessive-compulsive disorder , he Tourette syndrome And severe depressions.
However, its consumption can cause side effects like weight gain, dyskinesia, akathisia, lack of energy, sexual dysfunction, retrograde ejaculation, anxiety or insomnia.
12- Olanzapine
Olanzapine is a highly used drug for the treatment of schizophrenia, bipolar disorder and severe depressive episodes.
It structurally closely resembles clozapine, although it has a higher affinity for serotonin receptors than dopamine receptors.
Likewise, unlike most antipsychotics, olanzapine has a higher affinity for histamine and muscarinic receptors.
It is considered as one of the most effective antipsychotic drugs, although its consumption also causes side effects such as weight gain, impotence or insomnia.
13- Quetiapine
Finally, quetiapine is an atypical neuroleptic that is marketed under the name of Seroquel. It is used for the treatment of schizophrenia and bipolar disorders.
It has a high efficacy in the treatment of these diseases, reason why it has been established like one of the medicines of first choice. It also has the advantage of causing a limited range of side effects.
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