It is widely accepted that the actions of typical antipsychotics involve their ability to block the dopamine D2 receptors in the limbic system and striatum. It is thought that the blockade of receptors in the limbic system is the basis for the antipsychotic action; the reduction in the activity of the striatum contributes to the EPSs (and possibly the development, of TD); and the Di blockade of the hypothalamic-pituitary Inhibitors,research,lifescience,medical axis leads to hyperprolactinemia. The new drugs differ pharmacologically from conventional antipsychotics principally in their lower affinity for the

D2 receptor and relatively greater affinities for other neuroreceptors, including those for serotonin (5-HT1A, 5-HT2A, 5-HT2C, 5-HT3, 5-HT6, and 5-HT7) and norepinephrine (α1 and α2 subtypes), and in their ability to modulate glutamate receptor-mediated functions and behaviors.18 A pharmacological property that has been emphasized as critical for conferring atypical activity is the ratio between D2 and 5-HT2A receptor antagonism; Inhibitors,research,lifescience,medical a low ratio is characteristic Inhibitors,research,lifescience,medical of the new agents.19 In addition, they appear to exhibit, some degree of regional anatomic specificity, altering neurochemical activity in the limbic and frontal

cortical regions, while having very little effect on the corpus striatum.20 A variety of characteristics in addition to neuroreceptor affinities, including effects in animal models, potentially greater efficacy in treating negative, cognitive, and mood symptoms, and lower propensity to cause EPSs, have been used to identify and define the new antipsychotics.18,21 In this article, “atypical Inhibitors,research,lifescience,medical antipsychotic” refers to clozapine, olanzapine, quetiapine, risperidone, and ziprasidone. Amisulpridc has also been proposed as an atypical antipsychotic. However, because of its more traditional Inhibitors,research,lifescience,medical mechanism of action, we have not included it in this discussion. However, this does not negate the possibility that it may warrant, inclusion as a second generation of atypical antipsychotic.

Sertindole is not included because it is no longer available for clinical use. Because clozapine is the prototype and has unique risks and benefits, the others will be referred to as “newer” atypical antipsychotics. Conventional antipsychotic drugs – typified by low-potency of chlorpromazine, intermediatepotency perphenazine, and high-potency haloperidol – are those introduced click here before 1990. Comparison of conventional and atypical antipsychotic drugs Various claims have been made with regard to the superiority in efficacy and safety of the atypical antipsychotics relative to the conventional drugs. This has precipitated an important debate that is now underway regarding the appropriate role of the second-generation or atypical antipsychotic drugs in treating schizophrenia. At issue are the potential well-being of millions of persons with schizophrenia and billions of dollars.