Quetiapine: operation and side effects of this drug
Haloperidol, chlorpromazine, clozapine, risperidone, olanzapine, ziprasidone or quetiapine are the names some of the most well-known and used antipsychotics or neuroleptics . These are substances that allow 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 the aforementioned, quetiapine , to see what type of substance is, in what cases it is used and its possible side effects.
- Related article: "Types of antipsychotics (or neuroleptics)"
Quetiapine: what it is and mechanisms of action
As indicated in the introduction, quetiapine is a drug with psychoactive effects that is included in the atypical antipsychotics . It is a substance of the dibenzothiazepine type, being structurally closely related to olanzapine and especially to clozapine.
Its mechanism of action is based on its effects on dopamine and serotonergic receptors , acting by blocking the dopamine D2 receptors in the brain and in the serotonin receptors (which also reduces, which generates a general level of dopamine in most cortical structures is maintained to be this inhibitor of dopamine ).
This is a great advantage, since It is frequent that in schizophrenia there is an excess of dopamine at the mesolimbic level and a deficit of this in the mesocortical pathway, generating respectively positive symptoms (hallucinations, delusions, aggressiveness, impulsivity and disorganization) and negative (praise and apathy, among others). If we only try to reduce dopamine, as do the typical antipsychotics 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 which alterations would be generated in other areas with levels normative
In addition to its effect on dopamine and serotonin, it also has histaminergic and cholinergic effects , affecting and reducing the levels of both. This last factor causes certain somnolence and weight gain to occur, as well as hypotension and some physiological and memory alterations.
Quetiapine has a great advantage over other antipsychotics, and is that it usually does not generate any type of motor side effect. It is because of that subjects with psychotic problems who also suffer from Parkinson's can get to take it (as long as there is no dementia), and that is usually given as a drug to replace the treatment with clozapine or olanzapine when they give extrapyramidal side effects. Nor are there usually sexual effects, not altering prolactin levels. This indicates that their performance at the nigrostriatal and tuberoinfundibular level is minimal, generally not causing effects on the dopamine levels of these pathways.
Main indications and uses
Quetiapine is a psychotropic drug of great use for a large number of people, being used in clinical practice in different disorders and problems. The most common are the following.
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 (understanding as such those that add characteristics and / or generate an increase in activation, such as hallucinations and delusions) and negative ones (the opposite, as it happens in the poverty of thought and / or speech).
- You may be interested: "The 6 types of schizophrenia and associated characteristics"
2. Other psychotic disorders
Although schizophrenia is the main goal of most antipsychotics, it is not the only psychotic disorder that exists. People with disorders such as brief psychotic disorder, schizophreniform, schizoaffective and chronic delusional disorder can also benefit from the action of quetiapine.
3. Bipolar disorder
Some second-generation antipsychotics, including quetiapine, have been used in the treatment of manic episodes occurred 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.
- Related article: "Bipolar disorder: 10 features and curiosities you did not know"
4. Major depressive disorder
Since 2010, in some countries the use of quetiapine for the treatment of major depressive disorder has been approved . Although it is not the most recommended treatment, it is an alternative that has shown efficacy in those cases of depressed subjects who are not affected by conventional antidepressants.
- You may be interested: "Major depression: symptoms, causes and treatment"
Side effects and contraindications
As with all other drugs, The consumption of quetiapine can lead to a series of undesirable side effects . Therefore, among other things, its use must always be indicated and supervised by specialized doctors.
The most common side effect common to all antipsychotics is possible sedation or drowsiness of the subject, together with weight gain . It is also common for hypotension and possibly tachycardia to occur, which should be taken with special caution in patients with heart problems. Also hyperglycemia, and sometimes can contribute to the onset of diabetes (you have to be especially careful and see the doctor if thirst or extreme hunger, exaggerated increase in the urge to urinate or weakness, fruity breath or metallic taste as it could be symptom of a ketoacidosis that could become a danger to life, due to an excess of blood sugar).
Problems such as constipation, dry mouth and blurred vision , along with dizziness and hyperthermia, are also relatively frequent. Due to its anticholinergic action it can also generate memory alterations. Although it occurs in very few cases, it can lead to jaundice, endocrine problems and epileptic seizures. Asthenia, nervousness, akathisia, dryness and liver disorders may also occur.
In severe cases may occur fever, bleeding, falls, seizures, priapism , tachycardias or breathing difficulties. Also allergies and inflammation of the liver. Finally, the possibility of the neuroleptic malignant syndrome arising should be taken into account (reason why the doctor greatly regulates the dose and tends to increase it very little by little until reaching the intended levels).
Regarding the contraindications, quetiapine is contraindicated in all patients with heart problems or vulnerability to suffer them. It is also contraindicated in diabetic subjects, due to the weight gain and the glycemic level as well as the metabolic alterations that it can produce.
Neither should quetiapine users who require the use of other drugs (especially inhibitors of cytochrome P450 3A4 present in some medications for HIV or erythromycin, for example), being necessary to consult with your doctor.
By last, should be very careful pregnant and lactating . Do not drive or operate heavy machinery under its effects, especially due to the sedation it can cause.
- Navarro, B .; Montejo, A. & Martín, M. (2003). Utility of quetiapine in tardive dyskinesia. Actas Esp. Psiquiatr; 31 (6): 347-352.
- Rodríguez, J .; Fernández, R .; Iglesias, J. Carnero, M.A .; Quintero, P. & Pascual, F. (s.f.). Quetiapine Pharmacotherapeutic Information Bulletin. 3 (5). Xerencia de Atención Primaria de Ourense.
- Salazar, M .; Peralta, C .; Pastor, J. (2011). Manual of Psychopharmacology. Madrid, Panamericana Medical Publishing House.
- Srisurapanont, M .; Disayavanish, C. & Taimkaew, K. (2001). Quetiapine for schizophrenia (Cochrane Review). In: The Cochrane Library, 2. Oxford: Update Software.