Second generation antipsychotics atypicals

Current antipsychotics used to treat patients are divided into two classes the first generation antipsychotics (FGA) or typicals (e.g., chlorproma-zine, haloperidol, thioridazine, and loxapine) and the second generation antipsychotics (SGA) or atypicals (i.e., clozapine, olanzapine, quetiapine, risperidone, aripiprazole, ziprasidone, and asenapine). 

The first of the second-generation, or atypical, antipsychotics was clozapine. Clozapine (Clozaril) is relatively free of the movement disorders that characterize the first-generation drugs. This is true of, and defines, second-generation, atypical antipsychotics. It was a significant breakthrough for schizophrenia patients. 

The conventional antipsychotics have little effect on the negative psychotic symptoms such as autism, stupor and emotional withdrawal. The so-called atypical antipsychotics, or second-generation antipsychotics, like the heterocyclic compound risperidone, the benzamide sulpiride and several diben-zepines of which clozapine is the best known, have a broader spectrum which means that they also have an effect on the negative psychotic symptoms. Most share a common attribute of working on serotonin receptors as well as dopamine receptors. They have a low risk of extrapyramidal side effects. 

The effectiveness of the second generation antipsychotics (now called atypicals, because they have weak D2 blocking properties) show that this concept is not valid. Drugs like clozapine do not cause the Parkinsonian side effects even though they are very successful in terminating psychosis. 

Since the 1990s a range of new compounds have been introduced for the treatment of psychosis and schizophrenia. Although these compounds vary significantly in their pharmacological actions, they are collectively referred to as atypical antipsychotics or second-generation antipsychotics. The property they are all supposed to share is a lower... 

An important leap in the treatment of schizophrenia occurred in the late 1980s with the introduction of the first of a number of medications that offered a wider spectrum of action and relatively improved tolerability. Some of these atypical antipsychotics, also called second-generation antipsychotics, are listed in Table 5.13. 

Second-generation antipsychotics (SGAs) (also known as atypical antipsy-chotics), except clozapine, are the agents of first choice in treatment of schizophrenia. Growing, but stiU controversial, evidence supports that the SGAs (e.g., clozapine, olanzapine, risperidone, quetiapine, ziprasidone, and aripiprazole) have superior efficacy for treatment of negative symptoms, cognition, and mood. 

Dopamine partial agonist (dopamine stabilizer, atypical antipsychotic, third generation antipsychotic sometimes included as a second generation antipsychotic also a mood stabilizer)... 

Atypical antipsychotic (serotonin-dopamine antagonist, second generation antipsychotic)... 

When patients present in a manic episode, rapid remission of symptoms is required, particularly if the person is psychotic or experiencing severely disruptive behavior. In these cases, use of an antipsychotic medication is usual. These medications may include use of conventional or first generation antipsychotic medications, such as chloipromazine or haloperidol (Table 35.3). Recently, the second generation or atypical antipsycho tics have also shown efficacy in treatment of acute mania (American Psychiati ic Association, 2000). The latter agents are preferred due to their lower likelihood of inducing neuro-... 

Sulpiride is actually a first-generation drug but is classified with the second-generation antipsychotics due to ib atypical -like properties... 

These are dopamine antagonists. First generation antipsychotics ( GAs/typicals) are the older drugs, while second generation antipsychotics SGAs/atypicals) are the newer ones. It s a fairly arbitrary distinction, and although side effects differ, they overlap between the two groups. 

TABLE 34-10. Monitoring Protocol for Patients on Second-Generation (Atypical) Antipsychotics... 

Atypical antipsychotics The second generation or so-called atypical antipsychotics have chemical, pharmacological, and clinical properties that are different from those of the classical antipsychotics/ neuroleptics. The most commonly used atypicals include clozapine, olanzapine, risperidone, and quetiapine. 

In the late 1980s, clozapine a chlorpromazine like compound with a multiplicity of effects was rediscovered and termed an atypical neuroleptic. It appears to be the only genuinely atypical agent - that is an agent with significant beneficial treatment effects in the absence of EPS (see Wahlbeck et ah, 1999). A second generation of antipsychotics have succeeded clozapine been marketed as being atypical. 

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