Antipsychotic dopamine antagonists

As a consequence, several drugs have been developed by enhancing the side effect of another drug. For example, the mood-improving effect of iproniazid was discovered when it was tested as an antituberculous drug antidepressant inhibitors of neurotransmitter reuptake, like imipramine and desipramine, stem from the antipsychotic dopamine antagonist chlorpromazine, which itself was derived from Hi antihistaminics [35,36,51]. 

Atypical antipsychotic diugs Novel antipsychotic diugs serotonin/dopamine antagonists 5HT2A/D2 antagonists. 

D2 receptor, albeit with different specificity. Older examples of dopamine antagonists are chlorpromazine, haloperidol and many derivatives of these prototype compounds. Newer antipsychotic drugs such as risperidone, olanzapine and quetiapine have retained this mechanism of action, although no longer exclusively. 

Antipsychotics also have been used in the treatment of anorexia nervosa. The apparent role of dopamine in feeding and satiety involves increased receptor activity, producing symptoms similar to those found in anorexia nervosa. Thus, it seems reasonable to use dopamine antagonists to alter these behaviors. It also seems appropriate to use the sedative side effects of these drugs to decrease anxiety associated with eating. 

Consistent with the role of both serotonin and dopamine in OCD, some OCD patients benefit from treatment with the new serotonin-dopamine antagonists (also known as atypical antipsychotics), especially when there is inadequate response to an SSRI. On the other hand, other patients have no therapeutic response to these new agents, and the condition of still others is even worsened by these drugs. The atypical antipsychotics and serotonin dopamine antagonism are discussed in Chapter 11. 

What is an atypical antipsychotic From a pharmacological perspective, the atypical antipsychotics as a class may be defined in part as serotonin-dopamine antagonists (SDAs) (Fig. 11 — 16). Several other distinguishing pharmacological characteristics will be discussed in the following section. In this section, we will first discuss how the atypical antipsychotics all derive some of their atypical clinical properties from exploiting the different ways that serotonin and dopamine interact within the four key dopamine pathways in the brain. Thus, it is very important to understand serotonin-dopamine interactions in each of the four dopamine pathways. 

FIGURE 11-23. Here postsynaptic dopamine 2 receptors are being blocked by a serotonin-dopamine antagonist (SDA) atypical antipsychotic in the nigrostriatal dopamine pathway. This shows what would happen if only the dopamine 2 blocking action of an atypical antipsychotic were active— namely, the drug would only bind to postsynaptic D2 receptors and block them. However, see Figure 11-24. 

Which of the following serotonin dopamine antagonists (SDAs) is not considered to be a first line atypical antipsychotic drug ... 

Leucht S. Amisulpride - a selective dopamine antagonist and atypical antipsychotic results of a meta-analysis of randomized controlled trials. Int J Neuropsychopharmacol 2004 7 Suppl 1 S15-S20. 

Has atypical antipsychotic properties (i.e., antipsychotic action without a high incidence of extrapyramidal symptoms), especially at low doses, but not a serotonin dopamine antagonist... 

Atypical antipsychotic (serotonin-dopamine antagonist second generation antipsychotic also a mood stabilizer)... 

Conventional antipsychotic (neuroleptic, dopamine 2 antagonist, serotonin dopamine antagonist)... 

---