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)

Aripiprazole is the first dopamine D2/D3 receptor partial agonist approved for use in the treatment of psychiatric disorders, including schizophrenia, bipolar disorder, and unipolar depression in the US. To explore the functional activity of aripiprazole at dopamine D3 receptors, we established Chinese hamster ovary (CHO) cell lines stably expressing high and low densities of Ser-9 and Gly-9 variants of human dopamine D3 receptors and compared aripiprazole's dopamine D3 pharmacological properties with other marketed and non-approved dopamine D3 receptor modulating agents on inhibition of forskolin-stimulated cAMP accumulation. Maximal cell responses for dopamine were dependent on receptor expression levels, and all cells had similar potency for dopamine responses. Aripiprazole, terguride, bifeprunox, OPC-4392 (7-(3-[4-(2,3-dimethylphenyl)piperazinyl]propoxy)-2(1H)-quinolinone), (-)-3-PPP ((-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine), SDZ 208-912 (N-[(8 alpha)-2-chloro-6-methylergolin-8-yl]-2,2-dimethylpropanamide), BP897 (N-[4-[4-(2-Methoxyphenyl)-1-piperazinyl]butyl]naphthalene-2-carboxamide) and GR103691 (4'-Acetyl-N-[4-[4-(2-methoxyphenyl)piperazin-1-yl]butyl]biphenyl-4-carboxamide) behaved as partial agonists. Aripiprazole's intrinsic activity was similar to that of BP897 and GR103691, lower than that of terguride, bifeprunox, OPC-4392, and (-)-3-PPP, and higher than that of SDZ 208-912. The Gly-9 variant did not differ from the Ser-9 variant with respect to those agonist potencies and intrinsic activities. These compounds blocked the action of dopamine with a maximum effect equal to that of each compound alone. ACR16 (4-(3-Methanesulfonyl-phenyl)-1-propyl-piperidine), quetiapine, clozapine, olanzapine, ziprasidone, risperidone, and haloperidol acted as antagonists. Aripiprazole's unique activity at dopamine D3 receptors may translate into clinically relevant outcomes in patients with a variety of neuropsychiatric disorders.
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PMID:Characterization of aripiprazole partial agonist activity at human dopamine D3 receptors. 1883 71

Patients with schizophrenia often present mild to severe cognitive deficits which contribute to their social disability. Second-generation antipsychotics have shown only mild to moderate beneficial effects on cognition. The present case report suggests cognitive enhancing effects of aripiprazole, a dopamine partial agonist, shown to increase dopamine release in prefrontal cortex in animal studies.The patient was in his first-episode of schizophrenia, and had no previous exposure to first-generation antipsychotics. Before schizophrenia onset his cognitive functioning was poor and he could not attend regular courses to reach his high school degree; he started but was not able to attend the University courses for several years.After schizophrenia onset, he was treated, in sequence, with olanzapine, amisulpride and aripiprazole. During treatment with the first two second-generation antipsychotics, positive symptoms markedly improved while cognitive functioning remained poor. During treatment with aripiprazole, clinical remission was obtained and the patient was able to attend university courses and pass several examinations. Social functioning was markedly improved.Aripiprazole demonstrated cognitive enhancing effects in this patient. These effects were long-lasting and paralleled by a positive impact on social functioning.
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PMID:Cognitive-enhancing effects of aripiprazole: a case report. 1895 1

Rapid control of agitation is of critical importance in the treatment of acutely ill patients with schizophrenia. Both olanzapine and aripiprazole have been shown to be safe and effective in this setting, with each having somewhat different receptor binding affinity profiles. This 5-day, randomized, double-blind trial evaluated relative improvements in agitation in hospitalized patients who received orally dosed olanzapine (n = 306, 20 mg/d) or aripiprazole (n = 298, 15 mg/d, increasing to 30 mg/d as needed). Lorazepam was also given as needed (total dose, < or =4 mg/d) but not in place of a study drug dose increase. The primary efficacy measure was daily mean change from baseline in Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score. Secondary measures of positive symptoms and safety were also assessed. Significant improvements from baseline in PANSS-EC and secondary efficacy measures were seen for both olanzapine and aripiprazole (P < 0.001),with no between-group differences. A greater proportion of aripiprazole-treated patients received lorazepam at each visit compared with olanzapine-treated patients, but this difference was significant only at visit 5 (41.2% vs 31.0%, P = 0.033). Fasting glucose and triglycerides increased more significantly in olanzapine-treated patients (P = 0.030 and P < 0.001, respectively). Prolactin increased in the olanzapine group and decreased in the aripiprazole group with a significant between-group difference (P < 0.001). During the first 5 days of randomized treatment, olanzapine and aripiprazole displayed similar efficacy profiles for treating agitation associated with schizophrenia. Aripiprazole-treated patients had smaller increases in glucose and lipids, but no difference was observed between treatments in the proportion of patients experiencing categorical shifts in these measures.
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PMID:Olanzapine versus aripiprazole for the treatment of agitation in acutely ill patients with schizophrenia. 1901 27

Aripiprazole has been used effectively to treat schizophrenia in the clinic; however, its mechanisms of action are not clear. This study examined how short- and long-term aripiprazole treatment affects dopaminergic transmission in mesolimbic and nigrostriatal pathways. For comparison, the effects of haloperidol and olanzapine treatment were also examined. Aripiprazole significantly increased D2 receptor mRNA expression and decreased tyrosine hydroxylase (TH) mRNA expression in the ventral tegmental area (VTA) after 1- and 12-wk treatment, but had no effect in substantia nigra (SN) and nucleus accumbens (NAc). Aripiprazole also decreased dopamine transporter (DAT) binding density in NAc (for 1- and 12-wk treatment) and VTA (1-wk treatment). In contrast, haloperidol significantly increased D2 receptor binding density and decreased DAT binding density in NAc and caudate putamen (CPu) after 1- and 12-wk treatment, and it also decreases DAT binding in VTA after 12-wk treatment. Olanzapine had less widespread effects, namely an increase in D2 receptor mRNA in VTA after 12-wk treatment and decreased DAT binding in NAc after 1-wk treatment. These results suggest that aripiprazole has selective effects on the mesolimbic dopaminergic pathway. Selectively reducing dopamine synthesis in VTA is a possible therapeutic mechanism for the long-term efficacy of aripiprazole in controlling schizophrenia symptoms with reduced extrapyramidal side-effects.
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PMID:Aripiprazole differentially affects mesolimbic and nigrostriatal dopaminergic transmission: implications for long-term drug efficacy and low extrapyramidal side-effects. 1920 11

Aripiprazole is the first dopamine D(2)/D(3) receptor partial agonist approved for use in the treatment of psychiatric disorders including schizophrenia, bipolar disorder, and unipolar depression in the US. Aripiprazole has demonstrated a relatively favorable side effect profile compared to other commonly prescribed antipsychotics, including a low propensity for treatment-limiting extrapyramidal symptoms, hyperprolactinemia, and body weight gain. In an effort to elucidate aripiprazole's pharmacological activity in relation to clinically relevant fluctuation of dopamine D(2) receptor reserves, we compared the properties of aripiprazole to other antipsychotics, quetiapine, clozapine, olanzapine, ziprasidone, risperidone and haloperidol, a dopamine D(2) receptor partial agonist, bifeprunox, dopamine D(3) receptor modulators, BP897 (N-[4-[4-(2-Methoxyphenyl)-1-piperazinyl]butyl]naphthalene-2-carboxamide) and GR103691 (4'-Acetyl-N-[4-[4-(2-methoxyphenyl)piperazin-1-yl]butyl]biphenyl-4-carboxamide), and a 5-HT(1A) partial agonist, buspirone using forskolin-stimulated cAMP accumulation in clonal Chinese hamster ovary cell lines expressing low and high densities of human dopamine D(2S) receptors (hD(2S)-Low and hD(2S)-High, respectively). In hD(2S)-Low cells lacking receptor reserves for dopamine, all drugs antagonized dopamine responses, and their potencies correlated well with respective affinities. In hD(2S)-High cells possessing receptor reserves, all antipsychotics except aripiprazole antagonized dopamine responses, and their antagonist potencies were less than those in hD(2S)-Low cells treated with the equal dopamine concentration. In contrast, aripiprazole and bifeprunox acted as full agonists. BP897, GR103691 and buspirone acted as partial agonists. These data suggest that the level of receptor reserves influences antagonist potencies and side effects associated with antipsychotics. Aripiprazole's unique receptor reserve dependent properties may account for its favorable tolerability in the clinical setting.
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PMID:Receptor reserve-dependent properties of antipsychotics at human dopamine D2 receptors. 1921

Aripiprazole, a novel antipsychotic agent, has a unique pharmacological action (partial agonist) on the dopamine neurotransmission system. Aripiprazole has high affinity for dopamine D2 and D3 receptors (DRD2 and DRD3). We investigated whether the efficacy of aripiprazole can be predicted by a functional DRD3 gene polymorphism Ser9Gly (rs6280) as modified by clinical factors in Han Chinese hospitalized patients with acutely exacerbated schizophrenia. After hospitalization, the patients (n=128) were given aripiprazole for up to four weeks. Patients were genotyped for DRD3 Ser9Gly polymorphism by Restriction Fragment Length Polymorphism (RFLP) method. Clinical factors such as gender, age, duration of illness, education level, diagnostic subtype and medication dosage were recorded. Psychopathology was measured biweekly with the Positive and Negative Syndrome Scale (PANSS). The effects of genetic and clinical factors on PANSS performance after aripiprazole treatment were analyzed by a mixed model regression approach (SAS Proc MIXED). We found that, although the Ser carriers have numerically larger score reductions when compared with non-carriers in almost all PANSS dimensions, the difference of their effects are statically not significant. However, the clinical factors, including dosage of aripiprazole, age, duration of illness, and diagnostic subtype could influence PANSS performance after aripiprazole treatment. This study suggests that DRD3 Ser9Gly polymorphism may not contribute significantly to inter-individual differences in therapeutic efficacy of aripiprazole, but some clinical factors may predict treatment efficacy.
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PMID:Effects of the DRD3 Ser9Gly polymorphism on aripiprazole efficacy in schizophrenic patients as modified by clinical factors. 1930 29

Aripiprazole, a novel atypical antipsychotic that acts as a partial agonist at the dopamine D(2) receptors, has been reported to be effective in the treatment of chronic schizophrenia. However, the risks and benefits of using aripiprazole in the acute hospital setting to treat severe psychotic disorders are unclear. This naturalistic study assessed the effectiveness of aripiprazole monotherapy in a group of actively psychotic male patients (n = 10) with schizophrenia who were admitted to an inner-city acute psychiatric unit. Most patients (n = 7) responded to aripiprazole treatment, which was well tolerated and significantly ameliorated psychotic symptoms after 2-3 weeks. Patients who responded to it could be safely discharged on aripiprazole monotherapy. Side effects observed were mostly mild and transient, and included extrapyramidal symptoms (n = 1) and neutropenia (n = 1). Aripiprazole also remarkably attenuated dyskinetic movements in 1 patient with severe tardive dyskinesia, thereby suggesting that it may be useful in the treatment of other disorders that are also associated with dopamine dysfunction. Results showed that aripiprazole can be safely and effectively employed in the hospital setting to treat severely psychotic patients with schizophrenia, but further studies are required to establish the full range of adverse reactions and therapeutic indications associated with its use.
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PMID:Aripiprazole in the acute treatment of male patients with schizophrenia: effectiveness, acceptability, and risks in the inner-city hospital setting. 1941 63

Aripiprazole has been approved by regulatory agencies for the treatment of schizophrenia and bipolar I disorder. Although it is a dopamine partial agonist, it also has substantial binding affinity for the serotonin 5HT2A receptor. Several double-blind randomized clinical trials have established the efficacy and tolerability of aripiprazole within the dose range of 10-30 mg/day for schizophrenia, and 15-30 mg/day for manic or mixed states associated with bipolar I disorder. Relatively few comparative trials with other second-generation antipsychotics have been published for schizophrenia, with none available for bipolar disorder. The evidence so far suggests that in terms of efficacy for schizophrenia, aripiprazole is superior to placebo and haloperidol (long term), similar to perphenazine and risperidone, and inferior to olanzapine. Its tolerability profile in patients with schizophrenia appears superior to haloperidol, perphenazine, risperidone, and olanzapine. Efficacy in treating manic or mixed states was established in placebo-controlled trials. Among some patients with bipolar disorder, akathisia and gastrointestinal (GI) complaints can emerge at the start of treatment; however, the GI symptoms were time-limited in many instances. Appropriate dosing may also be important in individualizing therapy to improve tolerability, with lower starting doses becoming more important when adding to, or switching from, another antipsychotic. Aripiprazole appears to have a low propensity for weight gain, a favorable metabolic profile, and no association with hyperprolactinemia.
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PMID:A review of aripiprazole in the treatment of patients with schizophrenia or bipolar I disorder. 1941 92

The objectives of this 12-week multicenter open-label switching study were to evaluate the overall clinical efficacy, safety, and tolerability of aripiprazole in stable patients with schizophrenia or schizoaffective disorder, and to assess, in a naturalistic setting, whether such patients experience symptom worsening when switched from D2 receptor antagonists to aripiprazole (a D2 receptor partial agonist). Patients with schizophrenia or schizoaffective disorder in a symptomatically stable state were randomized to aripiprazole or standard-of-care antipsychotics. The Clinical Global Impression (CGI), Positive and Negative Syndrome Scale, and Investigator's Assessment Questionnaire were used monthly. The Udvalg for Kliniske Undersogelser side-effect rating scale scores and treatment emergent adverse events were recorded to assess the safety and tolerability of switching to aripiprazole from other antipsychotics. A total of 292 patients were randomly assigned to receive aripiprazole (N = 245) or non-aripiprazole antipsychotics (N = 47). Mean CGI-Improvement score at 12 weeks was 3.56+/-1.29 (95% confidence interval: 3.39-3.73) in the aripiprazole group, indicating that aripiprazole was effective in treating schizophrenic patients. Aripiprazole treatment resulted in improvement from baseline on all efficacy outcome measures, including Positive and Negative Syndrome Scale total, positive, negative, and general subscale, and CGI-Severity scores. In addition, after aripiprazole treatment, the remission rate was increased from 43.9% at baseline to 51.7% at 12 weeks. The proportion of patients with symptom worsening at 12 weeks was low (12.4%). Both Investigator's Assessment Questionnaire and Udvalg for Kliniske Undersogelser scores showed that there were fewer prolactin-related adverse events in the aripiprazole group than in the standard-of-care antipsychotics group (P<0.05). There were no significant between-group differences in time to failure to maintain remission and time to dropout. In the naturalistic setting, symptomatically stable outpatients with schizophrenia who were switched to aripiprazole showed clinically meaningful treatment benefits. The majority of patients was successfully switched from other antipsychotics without serious symptom exacerbation or adverse events over a course of 12 weeks.
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PMID:A 12-week, naturalistic switch study of the efficacy and tolerability of aripiprazole in stable outpatients with schizophrenia or schizoaffective disorder. 1945 28

Many patients fail to achieve an adequate response to antidepressant medication. Growing evidence suggests that atypical antipsychotics may augment antidepressant effects, resulting in a greater potential for response. Atypical antipsychotics possess pharmacological actions that are associated with antidepressant properties, including serotonin 5-HT(2) receptor antagonist and 5-HT(1A) and dopamine receptor partial agonist activity. In fact, the term 'atypical antipsychotic' is an unfortunate remnant of the early indication of these drugs in the treatment of schizophrenia. Soon after their introduction, the usefulness of atypical antipsychotics in bipolar disorder was firmly established and their use in the treatment of mood disorders has far outpaced their use in schizophrenia and other psychotic disorders. Aripiprazole has become the first agent to receive US FDA approval for the adjunctive treatment of unipolar depression. Most recently, Symbyax, a fluoxetine/olanzapine combination, received FDA approval for the acute treatment of treatment-resistant depression. This is the first medication to be FDA approved for this indication. In the present article, the usefulness of antipsychotics in the treatment of resistant unipolar depression is reviewed.
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PMID:Utility of atypical antipsychotics in the treatment of resistant unipolar depression. 1945 99


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