Atypicality of Atypical Antipsychotics

Abstract

Objective: To review the current definition of atypicality, discuss the unique features of each atypical antipsychotic, and determine whether the available drugs in this class really meet the classical definition of atypicality.Data Sources: A PubMed search was conducted to identify literature on the subject of this review, supported by additional articles based on the author's clinical knowledge and experience.Study Selection and Data Extraction: Relevant references were extracted and summarized in order to meet the objective of the article.Data Synthesis: Atypical antipsychotics are considered a major advance over conventional antipsychotics, primarily because they offer effective treatment alternatives that are relatively free of extrapyramidal symptoms. In fact, the term atypicality was originally used to describe antipsychotic agents with a minimal risk of causing extrapyramidal symptoms. However, over the years the definition has been modified such that there is currently no consensus on a true definition of atypicality for these agents. Each of the atypical antipsychotics (clozapine, risperidone, olanzapine, quetiapine, ziprasidone, and aripiprazole) commercially available in the United States is unique in terms of its pharmacologic profile, differing with respect to receptor-binding affinity, mechanism of action, and adverse events. Of the available atypical antipsychotics, clozapine and quetiapine have shown the lowest propensity to cause extrapyramidal symptoms. Although the risk of extrapyramidal symptoms is lower with risperidone and olanzapine than with conventional antipsychotics, risk increases with dose escalation. Data for ziprasidone indicate that the risk of extrapyramidal symptoms may be similar to that of risperidone and olanzapine. There is a concern of akathisia with aripiprazole; however, more experience with this agent is needed before definitive conclusions are made.Conclusion: If the definition of "atypical" antipsychotic is considered to be freedom from extrapyramidal symptoms, then, based on a comprehensive review of available data and clinical experience, clozapine and quetiapine appear to be the only true atypicals.( Prim Care Companion J Clin Psychiatry 2005;7:268-274)

1‐Cinnamyl‐4‐(2‐methoxyphenyl)piperazines: Synthesis, Binding Properties, and Docking to Dopamine (D2) and Serotonin (5‐HT1A) Receptors

“…Although very useful, these drugs produce a host of adverse side effects, without having any effect on the negative symptoms of schizophrenia [1]. More hope came with introduction of "atypical antipsychotics" [2], which cause significantly less extrapyramidal side effects.…”

“…More than fifty years ago, the discovery of drugs known today as "typical antipsychotics" significantly changed the pharmacological treatment of psychiatric disorders [1]. Although very useful, these drugs produce a host of adverse side effects, without having any effect on the negative symptoms of schizophrenia [1].…”

705 – Psychotropic drugs and HIV

“…A neurotoxicidade do VIH torna os doentes mais sensíveis aos efeitos adversos dos AP convencionais, especialmente os efeitos extrapiramidais (EEP) também conhecidos por sintomas parkinsónicos 25 . Neste contexto, os AP atípicos causam menos EEP do que os AP tradicionais [26][27][28] , o que pode melhorar a adesão ao tratamento antipsicótico. No entanto, há que estar atento ao risco de dislipidémias e hiperglicémia nos doentes que já estão medicados com terapêutica anti-retroviral [29][30][31] .…”

The Use of Second-Generation Antipsychotics and the Changes in Physical Growth in Children and Adolescents with Perinatally Acquired HIV

“…17 This prescribing trend is likely to continue following the U.S. Food and Drug Administration's (FDA) approval of risperidone use for the symptomatic treatment of irritability in children and adolescents with autism, 23 for treatment of schizophrenia in adolescents age 13 to 17 years, and for short-term treatment of manic or mixed episodes of type I bipolar disorder in youth age 10 to 17 years. 24 A major advantage of SGAs over conventional antipsychotics is their very low association with extrapyramidal symptoms, 25 however, growing evidence suggests an association between SGA treatment and excessive weight gain. Comprehensive reviews of randomized controlled pediatric trials suggest that the weight gain is particularly prominent in children and adolescents treated with olanzapine or risperidone, followed by quetiapine.…”