Quetiapine: how it works and side effects of this drug

This drug is used in both schizophrenia and other psychotic disorders.

Haloperidol, chlorpromazine, clozapine, risperidone, olanzapine, ziprasidone or quetiapine are the names of some of the best known antipsychotics or neuroleptics. some of the best known and most commonly used antipsychotics or neuroleptics.. They are substances that help to keep under control the symptoms of various mental disorders, especially schizophrenia and other psychotic disorders.

In this article we are going to talk about the last of those mentioned, quetiapineto see what type of substance it is, in which cases it is used and its possible side effects.

Quetiapine: what it is and mechanisms of action.

As stated in the introduction, quetiapine is a drug with psychoactive effects that is included in the group of atypical antipsychotics.. It is a dibenzothiazepine-type substance, being structurally closely related to olanzapine and especially to clozapine.

Its mechanism of action is based on its effects on dopaminergic and serotonergic receptors, acting by blocking the dopaminergic and serotonergic receptors.It acts by blocking dopamine D2 receptors in the brain and serotonin receptors (which it also reduces, which means that at a general level the level of dopamine in most cortical structures is maintained as it inhibits dopamine).

This is a great advantage, since it is frequent that in schizophrenia there is an excess of dopamine in the mesolimbic level and a deficit in the mesocortical pathway, generating respectively positive symptoms (hallucinations, delusions, aggressiveness, impulsivity and disorganization) and negative symptoms (alogia and abulia, among others). If we only try to reduce dopamine, as typical antipsychotics do in a non-specific way in the area to be treated, we would not be working and could even worsen the existence of the negatives, in addition to generating alterations in other areas with normative levels.

In addition to its effect on dopamine and serotonin, it also has histaminergic and cholinergic effectsaffecting and reducing the levels of both. This last factor causes some drowsiness and weight gain, as well as hypotension and some physiological and memory alterations.

Quetiapine has a great advantage over other antipsychotics, and that is that it generally does not generate any type of motor side effect. It is for this reason that subjects with psychotic problems who also suffer from Parkinson's disease can take it. (as long as there is no dementia), and it is usually given as a drug to replace clozapine or olanzapine treatment when extrapyramidal side effects occur. There are usually no sexual effects either, as it does not alter prolactin levels. This indicates that its action at nigrostriatal and tuberoinfundibular level is minimal, not generally causing effects on dopamine levels in these pathways.

Main indications and uses

Quetiapine is a very useful psychotropic drug for a large number of people, being used in clinical practice in different disorders and problems. The most common are the following.

1. Schizophrenia

The main and best-known indication for quetiapine is schizophrenia.. In this sense, quetiapine shows a great effect at the level of treatment of both positive symptoms (understood as those that add features and/or generate an increase in activation, such as hallucinations and delusions) and negative symptoms (the opposite, as occurs in the poverty of thought and/or speech).

2. Other psychotic disorders

Although schizophrenia is the primary target of most antipsychotics, it is not the only psychotic-type disorder that exists. People with disorders such as brief psychotic disorder, schizophreniform, schizoaffective and chronic delusional disorder may also benefit from the action of quetiapine.

3. Bipolar disorder

Some second-generation antipsychotics, among them quetiapine, have been used in the treatment of manic episodes occurring in subjects with bipolar disorder.. And not only in the treatment of crises, but also sometimes prophylactically to prevent them from happening. In addition, it also reduces the symptomatology of the depressive episodes that occur in this same disorder.

4. Major depressive disorder

From the year 2010, in some countries the use of quetiapine has been approved for the treatment of major depressive disorder.. Although it is not the most recommended treatment, it is an alternative that has shown efficacy in cases of depressed individuals who are not treated with conventional antidepressants.

Side effects and contraindications

As with all other drugs, the use of quetiapine can cause a number of undesirable side effects.. For this reason, among other things, its use should always be indicated and supervised by specialized physicians.

The most common side effect common to all antipsychotics is possible sedation or drowsiness of the subject, together with weight gain.. Hypotension and possibly tachycardia are also common, so special caution should be exercised in patients with cardiac problems. Also hyperglycemia, and sometimes it can contribute to the onset of Diabetes (special care should be taken and seek medical attention if there is extreme thirst or hunger, exaggerated increase in urination or weakness, fruity breath or metallic taste as it could be a symptom of a ketoacidosis that could become life threatening, due to an excess of sugar in the blood).

Problems such as constipation, dry mouth and blurred vision, together with dizziness and hyperthermia are also relatively frequent.together with dizziness and hyperthermia, are also relatively frequent. Due to its anticholinergic action, it can also cause memory alterations. Although it occurs in very few cases, it can produce jaundice, endocrine problems and epileptic seizures. Asthenia, nervousness, akathisia, dryness and hepatic alterations may also occur.

In severe cases, fever, bleeding, falls, convulsions, priapism, tachycardia or tachycardia difficulties may occur.tachycardia or respiratory difficulties. Also allergies and liver inflammation. Finally, the possibility of neuroleptic malignant syndrome should be taken into account (which is why the physician regulates the dose to a great extent and tends to increase it very gradually until the desired levels are reached).

Contraindications

Regarding contraindications, quetiapine is contraindicated in all patients with cardiac problems or vulnerability to heart problems. or vulnerability to suffer from them. It is also contraindicated in diabetic subjects, due to weight gain and glycemic level as well as the metabolic alterations it can produce.

Quetiapine should also not be taken by those subjects who require the use of other drugs (especially cytochrome P450 3A4 inhibitors present in some HIV medications or erythromycin, for example), and they should consult their physician.

Finally, great caution should be exercised by pregnant women and nursing mothers.. Do not drive or operate heavy machinery under its effects, especially due to the sedation it may cause.