Atypical antipsychotic

Atypical neuroleptics ( syn. atypical antipsychotics, atypicals or short ) are a heterogeneous group of drugs that are used in the treatment of schizophrenia and other psychoses. Since the 1950s, are " typical antipsychotics " such as haloperidol used for this purpose ( first generation antipsychotics ).

Since the 1990s, various other mechanisms of action based on neuroleptics were developed for the same indications. To this group of antipsychotics to the "second " generation clearly distinguished from those of the " first " atypical antipsychotic used for this the term.

The term atypical antipsychotic was with the introduction of clozapine in the treatment of schizophrenia. The new substances to cause the typical side effects of neuroleptics rare, especially rare cause extrapyramidal motor disorders ( EPMS ) and tardive dyskinesia. However, they are different, compared with often severe side effects of new substances.

Properties

Extrapyramidal disorders

Textbooks of psychiatry and pharmacology call the EPMS lower rate ( EPMS stands for Extrapyramidal motor disturbances ) as a characteristic community of atypicals. However, there are no limits or quantified findings. In general, EPMS and dyskinesias are largely absent in atypical N. " already in antipsychotic dosages ." However, for individual atypicals are studies in which these substances showed a "typical " neuroleptics comparable incidence of parkinsonism (eg risperidone vs. Flupentixol ).

Effect on negative symptoms

Atypicals are with equally good effect on positive symptoms better efficacy against the so-called negative symptoms of psychosis have than the classical neuroleptics. Authors such as Möller or Benkert / Hippius this respect by opposing viewpoints. The test instruments used ( va rating scales ) is not a clear demarcation and no etiologic association of negative symptoms. Symptoms such as withdrawal or depressed mood may in individual cases are arbitrarily designated as primary ( expression of the disease ) or secondary ( due to the personal situation, hospital environment, etc.). A substantial progress has not yet been demonstrated.

Molecular Pharmacological Properties

In addition to the antagonistic effect of traditional neuroleptics to dopamine receptors of the D2 subtype show the most atypical neuroleptics a pronounced antagonistic effect on serotonin receptors of type 5 -HT2A. The ratio of the affinity of a neuroleptic drug for the 5-HT2A receptor to its affinity for D2 receptors, also called Meltzer index prediction atypical antipsychotic properties is used. On the inhibition of 5 -HT2A receptors is together with the antidopaminergic effect clinical improvement (especially the negative symptoms) and the lower EPMS - rate based. Other molecular pharmacological properties, such as the Partialagonismus of aripiprazole and amisulpride on dopamine receptors, can be used to explain atypical neuroleptic properties. Also, a specific role of the dopamine D4 receptor will be discussed.

Drugs

The following substances are included among the atypicals:

  • Clozapine group ( tricyclic atypicals ): Clozapine ( single Atypikum without EPMS - risk)
  • Clothiapine
  • Zotepine
  • Olanzapine
  • Quetiapine ( clozapine after the second lowest - risk EPMS )
  • Risperidone
  • Paliperidone
  • Ziprasidone
  • Aripiprazole ( in the broad sense structurally related to risperidone / ziprasidone )
  • Sertindole
  • Lurasidon
  • Asenapine
  • Sulpiride
  • Amisulpride

The classification of sulpiride is handled inconsistently, since the term Atypikum only after introduction of the Sulpirids became popular and in its assessment in practice did not matter. The analog substance amisulpride should not be considered as safe Atypikum also. The two benzamides differ pharmacologically from the other neuroleptics, both the older and the newer agents.

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