Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Atypical antipsychotic agents have a broad range of therapeutic efficacy, a relatively low incidence of causing extrapyramidal adverse effects, and a low tardive dyskinesia profile. This has led to very rapid growth in the use of these compounds as broad-spectrum psychotropic agents, and it has been reported that more than 70% of prescriptions for atypical antipsychotic medications are being used for conditions other than schizophrenia. In the area of bipolar disorder, in particular, atypical antipsychotic agents appear to positively affect illness outcome, and are considered potential first-line treatment agents. Quetiapine was approved by the US Food and Drug Administration in 1997, and is currently marketed in the US to treat schizophrenia. Aripiprazole was recently approved for the treatment of schizophrenia by the US Food and Drug Administration in late 2002, and is being used increasingly in clinical settings. Recent reports suggest that quetiapine and aripiprazole are valuable additions to the psychotropic armamentarium for the treatment of mood and anxiety disorders. Data from clinical trials and clinical reports are discussed herewith.
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PMID:Treatment for mood and anxiety disorders: quetiapine and aripiprazole. 1285 36

Aripiprazole is a novel atypical antipsychotic for the treatment of schizophrenia. It is a D2 receptor partial agonist with partial agonist activity at 5-HT1A receptors and antagonist activity at 5-HT2A receptors. The long-term efficacy and safety of aripiprazole (30 mg/d) relative to haloperidol (10 mg/d) were investigated in two 52-wk, randomized, double-blind, multicentre studies (using similar protocols which were prospectively identified to be pooled for analysis) in 1294 patients in acute relapse with a diagnosis of chronic schizophrenia and who had previously responded to antipsychotic medications. Aripiprazole demonstrated long-term efficacy that was comparable or superior to haloperidol across all symptoms measures, including significantly greater improvements for PANSS negative subscale scores and MADRS total score (p<0.05). The time to discontinuation for any reason was significantly greater with aripiprazole than with haloperidol (p=0.0001). Time to discontinuation due to adverse events or lack of efficacy was significantly greater with aripiprazole than with haloperidol (p=0.0001). Aripiprazole was associated with significantly lower scores on all extrapyramidal symptoms assessments than haloperidol (p<0.001). In summary, aripiprazole demonstrated efficacy equivalent or superior to haloperidol with associated benefits for safety and tolerability. Aripiprazole represents a promising new option for the long-term treatment of schizophrenia.
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PMID:Efficacy and safety of aripiprazole vs. haloperidol for long-term maintenance treatment following acute relapse of schizophrenia. 1546 64

Serotonin (5-HT)-receptor-based mechanisms have been postulated to play a critical role in the action of the new generation of antipsychotic drugs (APDs) that are usually referred to as atypical APDs because of their ability to achieve an antipsychotic effect with lower rates of extrapyramidal side effects (EPS) compared to first-generation APDs such as haloperidol. Specifically, it has been proposed by Meltzer et al. [J. Pharmacol. Exp. Ther. 251 (1989) 238] that potent 5-HT2A receptor antagonism together with weak dopamine (DA) D2 receptor antagonism are the principal pharmacologic features that differentiate clozapine and other apparent atypical APDs from first-generation typical APD. This hypothesis is consistent with the atypical features of quetiapine, olanzapine, risperidone, and ziprasidone, which are the most common treatments for schizophrenia in the United States and many other countries, as well as a large number of compounds in various stages of development. Subsequent research showed that 5-HT1A agonism may be an important consequence of 5-HT2A antagonism and that substitution of 5-HT1A agonism for 5-HT2A antagonism may also produce an atypical APD drug when coupled with weak D2 antagonism. Aripiprazole, the most recently introduced atypical APD, and a D2 receptor partial agonist, may also owe some of its atypical properties to its net effect of weak D2 antagonism, 5-HT2A antagonism and 5-HT1A agonism [Eur. J. Pharmacol. 441 (2002) 137]. By contrast, the alternative "fast-off" hypothesis of Kapur and Seeman [Am. J. Psychiatry 158 (2001) 360] applies only to clozapine and quetiapine and is inconsistent with the "slow" off rate of most atypical APDs, including olanzapine, risperidone and ziprasidone. 5-HT2A and 5-HT1A receptors located on glutamatergic pyramidal neurons in the cortex and hippocampus, 5-HT2A receptors on the cell bodies of DA neurons in the ventral tegmentum and substantia nigra and GABAergic interneurons in the cortex and hippocampus, and 5-HT1A receptors in the raphe nuclei are likely to be important sites of action of the atypical APDs. At the same time, evidence has accumulated for the important modulatory role of 5-HT2C and 5-HT6 receptors for some of the effects of some of the current APDs. Thus, 5-HT has joined DA as a critical target for developing effective APDs and led to the search for novel drugs with complex pharmacology, ending the exclusive search for single-receptor targets, e.g., the D3 or D4 receptor, and drugs that are selective for them.
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PMID:Serotonin receptors: their key role in drugs to treat schizophrenia. 1464 74

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, drug interactions, and dosage and administration of aripiprazole are discussed. Aripiprazole is a third-generation antipsychotic agent indicated for use in the treatment of schizophrenia. Unlike other antipsychotics, aripiprazole demonstrates mixed D2 and serotonin (5-HT1A) receptor agonist-antagonist activity that is hypothesized to improve schlzophrenia's positive and negative symptoms; the drug has been referred to as a dopamine-serotonin stabilizer. Aripiprazole is well absorbed, with peak plasma concentrations occurring within three to five hours after administration. The oral availability is 87%. The mean elimination half-life is about 75 hours for aripiprazole and 94 hours for its active metabolite. In controlled, randomized, multicenter trials, aripiprazole has demonstrated efficacy in the treatment of schizophrenia comparable to that of haloperidol and superior to placebo. In a single clinical trial, aripiprazole was superior to placebo in the treatment of acute mania. The most frequent adverse effects are headache, anxiety, insomnia, nausea, vomiting, and lightheadedness. Because aripiprazole is a substrate of both cytochrome P-450 isoenzymes 3A4 and 2D6, there is a potential for other drugs to affect its metabolism. The recommended starting dosage is 10 or 15 mg daily, preferably administered with meals. Aripiprazole offers an alternative to second-generation antipsychotic agents in the treatment of schizophrenia.
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PMID:Aripiprazole. 1468 20

This paper is an overview of recently published research concerning the neuroleptic drug aripiprazole. Aripiprazole is an antipsychotic drug with high affinity for D(2)- and D(3)-receptors and the dopamine autoreceptor. It also has serotonin 5-HT(1A)-receptor partial agonist and 5-HT(2A)-receptor antagonist properties. It is prescribed in the treatment of schizophrenia and is under the treatment of schizophrenia and schizoaffective investigation for treatment of bipolar disorder. The drug is given by mouth in an initial dose of 10 or 15 mg once daily. The dose may be adjusted at intervals of not less than 2 weeks up to a maximum of 30 mg daily. It appears to be useful in disorder and has a better side-effect profile than haloperidol.
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PMID:Focus on aripiprazole. 1500 16

This review examines the development of dopamine partial agonists as a new class of antipsychotic agents. Partial agonists have a lower intrinsic activity at receptors than full agonists, allowing them to act either as a functional agonist or a functional antagonist, depending on the surrounding levels of naturally occurring neurotransmitter (full agonist). In the absence of a full agonist, partial agonists show functional agonist activity, binding to the receptor to produce a response. In the presence of a full agonist, partial agonists show functional antagonist activity, as receptor binding reduces the response from that seen with the full agonist. A partial agonist at dopamine D(2) receptors therefore offers an attractive option for the treatment of schizophrenia. It should act as a functional antagonist in the mesolimbic dopamine pathway, where excessive dopamine activity is thought to cause positive symptoms, but show functional agonist activity in the mesocortical pathway, where reduced dopamine activity is thought to be associated with negative symptoms and cognitive impairment. In addition, it should avoid the complete blockade of the nigrostriatal or tuberoinfundibular pathways, associated with extrapyramidal symptoms (EPS) and elevated prolactin levels, respectively. Clinical trials with aripiprazole - a new antipsychotic, which shows partial agonist activity at D(2) receptors and serotonin 5-HT(1A) receptors, and antagonist activity 5-HT(2A) receptors - have demonstrated the value of this treatment approach. Aripiprazole produced significant improvements in positive and negative symptoms in short- and long-term studies of patients with schizophrenia or schizoaffective disorder. Improvements occurred rapidly after the start of treatment, and were sustained throughout studies lasting up to 52 weeks. Significantly more patients responded to aripiprazole treatment than to haloperidol in the 52-week study, and aripiprazole-treated patients showed significantly greater improvements in negative and depressive symptoms than those receiving haloperidol. Aripiprazole treatment was well tolerated in both short- and long-term studies, showing a low liability for EPS and hyperprolactinemia, a lack of QTc prolongation, and minimal weight gain or sedation. In conclusion, the findings from clinical studies of aripiprazole show that dopamine partial agonists offer a novel, effective and well-tolerated treatment approach for patients with schizophrenia.
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PMID:Dopamine partial agonists: a new class of antipsychotic. 1501 5

We review evidence from randomized, placebo-controlled studies of patients with schizophrenia or schizoaffective disorder, which compared 2 or more doses of an antipsychotic to calculate the dose-response curve for each first-generation (typical) antipsychotic (FGA) or second-generation (atypical) antipsychotic (SGA) and as a group (based on dose equivalence). We identified the near-maximal effective dose (ED; ie, the threshold dose necessary to produce all or almost all the clinical responses for each drug). In randomized, fixed-dose studies of SGAs, the near-maximal efficacy dose for olanzapine may be greater than 16 mg; for risperidone, it is 4 mg; and for ziprasidone, it is 120 mg. Risperidone at 2 mg daily is 50% less efficacious than higher doses. Olanzapine at about 6 mg is approximately 33% less effective than higher doses. Aripiprazole at 10 mg daily was fully efficacious. Doses of clozapine well above 400 mg are necessary for optimal treatment of many schizophrenia patients. We found 3.3 to 10 mg haloperidol to be the near-maximal ED range. We find no evidence that doses higher than these are more effective. We failed to find that high doses of haloperidol (or all other first-generation comparison drugs converted to equivalent doses) were less effective than medium doses (3.3 to 10 mg). While high-dose FGAs are not less effective, we feel it is important not to avoid using high dose to avoid excessive toxicity.
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PMID:Dose response and dose equivalence of antipsychotics. 1616 Jun 32

Recently there has been increased concern over the side effects of the atypical antipsychotic drugs, including diabetes, hyperlipidemia and obesity. The relationship between diabetes and antipsychotic drugs requires a careful analysis. Patients with schizophrenia are known to suffer from diabetes more often than the general population. In addition, a number of case reports indicate that the conventional antipsychotic as well as atypical antipsychotic drugs produce diabetes. Clozapine and olanzapine, in particular, have been implicated producing diabetes as well as diabetic ketoacidosis. Epidemiological surveys have supplemented the case reports, finding increased incidence of diabetes in patients treated with atypical antipsychotic agents, but these surveys have not yielded consistent results regarding the differential effects of the various atypical antipsychotic drugs. The mechanism by which antipsychotic agents produce diabetes is not elucidated. Weight gain and consequent alteration in triglycerides and cholesterol have been known to occur frequently with olanzapine and clozapine. The ensuing metabolic syndrome itself may cause insulin resistance and diabetes. In the absence of definitive scientific data on the differential effects of antipsychotic drugs in inducing diabetes, clinical prudence and careful monitoring of all patients on atypical antipsychotic drugs is necessary. Aripiprazole and ziprasidone have not been shown to increase weight or produce diabetes, but more information on the diabetogenic effects of ziprasidone and aripiprazole is needed. In order to assess the differential effects of atypical antipsychotic drugs in producing diabetes and the mechanisms by which they produce this reaction, further research is necessary.
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PMID:Side effects of atypical antipsychotic drugs. 1528 97

Aripiprazole is an atypical antipsychotic agent with an intrinsic dopamineagonist activity of 30 %. Aripiprazole exerts additional partial agonist action on 5-HT (1A) receptors and has antagonist properties at 5-HT (2A) receptors. Controlled studies demonstrated an effectiveness in acute relapse of schizophrenic psychosis, chronical schizophrenic and schizoaffective disorders. Aripiprazole was effective in the treatment of productive psychotic and negative symptoms. Compared to other antipsychotics aripiprazole demonstrated a favourable profile of side effects: only slight changes of body weight, mild extrapyramidal symptoms, no prolactin elevation and no significant changes in QTc interval. The efficacy in the long term treatment of schizophrenia seems to be similar to other antipsychotics (e. g. olanzapine). The first evaluations of studies with patients with bipolar disorders showed a significant efficacy in the treatment of mania.
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PMID:[Aripiprazole: a new atypical antipsychotic drug]. 1536 12

Aripiprazole, an atypical antipsychotic with a novel method of action, has only recently been awarded a license in the UK. We report our first patient to receive this drug, who had treatment-resistant schizophrenia and developed neuroleptic malignant syndrome (NMS) with aripiprazole. To our knowledge, this is the first published case report involving aripiprazole and NMS in a potentially fatal medical emergency. Further experience with this drug should indicate whether this is an isolated case (as described with other atypical antipsychotics) or constitutes a more serious risk than that suggested by the relatively beneficial therapeutic profile described in the literature to date.
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PMID:Aripiprazole and neuroleptic malignant syndrome. 1548 22


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