Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Negative symptoms are considered the most debilitating and refractory aspect of schizophrenia, being associated with poor social, occupational and global outcomes. Conventional antipsychotics have limited efficacy against these symptoms and poor tolerability profiles. Atypical antipsychotics are an alternative treatment, and this 12-week, randomised, flexibly dosed study compared the efficacy, safety and tolerability of quetiapine and olanzapine in this regard. Of the 40 patients who entered the study (32 male; 8 female), 19 were randomised to quetiapine (mean dose 637 mg/day, mean treatment duration 80 days) and 21 to olanzapine (mean dose 16 mg/day, mean treatment duration 78 days). Quetiapine and olanzapine were similarly effective: in each treatment group significant improvements at Week 12 were observed for negative symptom scores on the SANS and the PANSS, and for subscale scores of affective flattening and alogia on the SANS. Both treatments were well tolerated in this patient population, with no worsening of extrapyramidal symptoms in either case. Anxiety and insomnia were the most common adverse events (> or =7% of patients in each group), but were not drug-related. Although this is a small study with limited power, the results support the effectiveness of quetiapine and olanzapine in treating the negative symptoms of schizophrenia.
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PMID:Quetiapine versus olanzapine for the treatment of negative symptoms in patients with schizophrenia. 1678 11

Quetiapine, a dibenzothiazepine derivative, is an atypical antipsychotic, multireceptor antagonist that has a preclinical profile similar to clozapine. Randomized studies have demonstrated the efficacy of quetiapine relative to placebo in the treatment of acute relapse and the long-term management of schizophrenia. Quetiapine is generally well tolerated relative to other antipsychotic medications, although side effects include sedation, orthostatic hypotension, anticholinergic and metabolic side effects. The purpose of this article is to critically review the current literature on quetiapine with an emphasis on emergent themes and key findings in the use of this agent for the treatment of schizophrenia. There are also continued efforts to understand, predict and manage the side-effect risk with quetiapine.
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PMID:Quetiapine: efficacy, tolerability and safety in schizophrenia. 1683 Nov 13

Quetiapine is a novel and atypical antipsychotic agent with serotonin 5-HT2A antagonism higher than D2 blockade. However, it has the lowest affinity for serotonin receptors among atypical antipsychotics. Besides its D2 blockade, it is not as great as seen with risperidone and olanzapine and is even less than that of clozapine. Open-label and controlled trials suggest efficacy of quetiapine as an adjunct therapy in patients with obsessive-compulsive disorder, refractory to treatment with selective serotonin reuptake inhibitors. There is one report of quetiapine exacerbating obsessive-compulsive symptoms (OCS). We report 5 cases with bipolar I disorder (n = 3), psychotic depression (n = 1), and schizophrenia (n = 1) in which quetiapine produced de novo OCS. The underlying pathogenetic mechanisms and the risk factors for this action of quetiapine and of atypical antipsychotics, in general, are not yet known. The description of 5 patients with different diagnoses supports the issue of OCS exacerbation or induction with atypical antipsychotics. Clinicians' awareness and close monitoring of the patients is warranted.
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PMID:Quetiapine-induced obsessive-compulsive symptoms: a series of five cases. 1685 58

Neurocognitive impairment is a core feature in the pathology of schizophrenia and considered to be relatively persistent towards psychopharmacological interventions. There are hints that atypical antipsychotics can influence neurocognitive dysfunctions more favorable than conventional compounds. But little is known about differences in efficacy on neurocognitive dysfunctions linked to the variety of receptor profiles of different atypical antipsychotics. This study compared the effects of the atypical antipsychotics quetiapine and olanzapine on cognitive function in patients with an acute episode of schizophrenia. Patients were randomized to receive quetiapine or olanzapine for 8 weeks. Cognitive function was assessed at baseline, week 4 and week 8. Efficacy was assessed weekly using the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Improvement Scale (CGI). Tolerability was assessed each week using the Extrapyramidal Symptom Rating Scale (ESRS), the Barnes Akathisia Scale (BAS) and the Udvalg for Kliniske Undersogelser Side Effect Rating Scale (UKU). In total, 52 patients were enrolled in the study. Data from the 33 patients who completed cognitive assessments at two or more time points out of three (baseline, Week 4 and Week 8) are analyzed here. Both quetiapine and olanzapine improved global cognitive index z-scores, however, this was more marked with quetiapine. Between-group comparisons showed significantly greater improvements in reaction quality/attention with quetiapine than olanzapine. Quetiapine and olanzapine produced significant improvements from baseline to week 8 in PANSS total and subscale scores. Both treatments were well tolerated, especially no EPS occurred during 8 weeks of treatment. Both quetiapine and olanzapine improved cognition; however, the improvement in cognitive index scores was more marked in patients receiving quetiapine. Furthermore, quetiapine produced a significantly greater improvement in reaction quality/attention than olanzapine.
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PMID:Efficacy of olanzapine versus quetiapine on cognitive dysfunctions in patients with an acute episode of schizophrenia. 1762 25

Evidence suggests that neurocognitive impairment is a key factor in the pathology of schizophrenia and is linked with the negative symptoms of the disease. In this study the effects of the atypical antipsychotics quetiapine and risperidone on cognitive function in patients with schizophrenia and with predominantly negative symptoms were compared. Patients were randomly assigned to double-blind treatment with quetiapine or risperidone for 12 weeks. Cognitive function was assessed at baseline, Week 6 and Week 12. Efficacy was assessed using the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS) at baseline, Week 6 and Week 12. Extrapyramidal side-effects were assessed each week using the Simpson-Angus Scale (SAS), adverse events were recorded as additional indicators of tolerability throughout the trial. In total, 44 patients were enrolled in the study. Data from the 34 patients who completed cognitive assessments at two or more time points out of three (baseline, Week 6 and Week 12) are analysed here. Quetiapine improved significantly global cognitive index z-scores at both Week 6 (p<0.001 vs. baseline) and Week 12 (p<0.01 vs. baseline), whereas risperidone improved significantly global cognitive index z-scores at Week 12 (p<0.05). Between-group comparisons at Week 6 showed significantly greater improvements in working memory and verbal memory with quetiapine than risperidone (p<0.05) and a significantly greater improvement in reaction quality/attention with quetiapine than risperidone at Week 12 (p<0.05). Quetiapine and risperidone produced significant improvements from baseline in PANSS total (p<0.001) and subscale scores at Week 12. Significant improvements in SANS total score were also seen in both the quetiapine (p<0.001) and risperidone (p<0.01) groups at Week 12 compared with baseline. SAS scores, measuring the incidence of extrapyramidal side-effects, were higher in patients receiving risperidone compared with those receiving quetiapine, and significant differences were seen at Weeks 3, 4, 5 and 7. Both quetiapine and risperidone improved cognition according to changes in cognitive index scores from baseline to Week 12. These results suggest that quetiapine and risperidone provide valuable treatment options for patients with schizophrenia with predominantly negative symptoms. Also, the improvements in cognition following treatment with quetiapine and risperidone may enhance long-term outcomes for these patients.
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PMID:Effects of risperidone and quetiapine on cognition in patients with schizophrenia and predominantly negative symptoms. 1762 31

Quetiapine is an atypical antipsychotic agent approved by the FDA for the treatment of schizophrenia, acute mania, and bipolar depression. Recently, reports of medication abuse, particularly intranasal and i.v. abuse, have been described. Three cases of oral misuse of quetiapine are presented and clinical implications are discussed. Clinicians should exercise caution when prescribing quetiapine to patients at risk for substance abuse.
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PMID:Additional evidence of the abuse potential of quetiapine. 1771 13

Quetiapine is a widely used second-generation antipsychotic that is effective in the treatment of schizophrenia and bipolar mania. In recent years, various publications have suggested the possibility that, in some patients, higher than licensed dosages are necessary for full therapeutic effect. A 'high-dose' theory of quetiapine activity has developed, leading many prescribers to disregard the formal upper limit of the quetiapine dosage range (750 or 800 mg/day, depending on local labelling). In this review, we examine the clinical and neuroimaging data relating to the use of quetiapine in acute exacerbations of schizophrenia. Fixed-dose efficacy studies of immediate-release (IR) quetiapine suggest dosages of quetiapine of 150-450 mg/day are more effective than placebo and no less effective than dosages of 600 or 750 mg/day. A fixed-dose study of extended-release quetiapine indicated that dosages of 600 and 800 mg/day were equally efficacious and numerically superior to 400 mg/day. Dosages of IR quetiapine averaging between 254 and 525 mg/day have been shown to be equivalent in efficacy to standard dosages of conventional and other atypical antipsychotics. Pooled data support these findings. Effectiveness studies using quetiapine in daily doses averaging between 565 and 653 mg revealed quetiapine to be somewhat less effective than some comparator drugs. Support for the use of high-dosage quetiapine (>800 mg/day) is very limited: case reports, albeit numerous, describe quetiapine as showing therapeutic effects only at dosages above the licensed range; some data suggest widespread use of higher dosages in practice; and neuroimaging data suggest inadequate dopamine receptor occupancy at standard dosages (although these findings may reflect the low affinity of quetiapine for dopamine receptors). Overall, robust controlled data strongly suggest that the standard dosage range for quetiapine is appropriate for clinical use. The balance of evidence does not support the belief that higher dosages are required for full therapeutic effect, although higher dosage trials are ultimately required to confirm or refute this hypothesis.
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PMID:Quetiapine: dose-response relationship in schizophrenia. 1807 14

This article reviews the published clinical data on schizophrenic patients managed with the new formulation of quetiapine, the once-daily extended release quetiapine fumarate (quetiapine XR). Quetiapine XR has been developed to reduce the frequency of quetiapine dosing by introducing once-daily administration and to simplify the treatment initiation schedule. Quetiapine XR (400 to 800 mg/day) was effective versus placebo across a broad range of symptom domains in acute schizophrenia and was as well tolerated as the immediate release (IR) formulation. Rapid dose escalation of quetiapine XR (300 mg on day 1,600 mg on day 2, and 800 mg on day 3) was also well tolerated, with a therapeutically effective dose reached by day 2. Clinically stable patients with schizophrenia receiving quetiapine IR (400-800 mg/day) can be switched to an equivalent once-daily dose of quetiapine XR (400-800 mg/day once-daily) without clinical deterioration or compromise in tolerability. Evidence from a clinical trial has shown that patients with schizophrenia who had a history of unsatisfactory treatment (tolerability or efficacy) on typical or atypical antipsychotic experienced improved efficacy and clinical benefit when switched to quetiapine XR. Once-daily quetiapine XR (400-800 mg/nap) was effective compared with placebo in preventing relapse in patients with clinically stable schizophrenia, and was well tolerated during long-term use. Patients could be switched from their ongoing antipsychotic to quetiapine XR within 4 days without compromising efficacy, enabling a dose of 600 mg/day and 800 mg/day to be reached by Day 2 and Day 3 respectively. This new, once-daily formulation of quetiapine offers psychiatrists and patients valuable new treatment options for the short and long-term treatment of schizophrenia.
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PMID:[Administration of once-daily extended release quetiapine in schizophrenic disorders]. 1851 Feb 63

Quetiapine was developed in 1985 by scientists at AstraZeneca (formerly Zeneca) Pharmaceuticals. It received official US Food and Drug Administration approval in September 1997 and approval in Germany in 2000. Since then, quetiapine has been used in the treatment of severe mental illness in approximately 70 countries including Canada, most Western European countries, and Japan. Quetiapine is a dibenzothiazepine derivative with a relatively broad receptor binding profile. It has major affinity to cerebral serotonergic (5HT(2A)), histaminergic (H1), and dopaminergic D(1) and D(2) receptors, moderate affinity to alpha(1)- und alpha(2)-adrenergic receptors, and minor affinity to muscarinergic M1 receptors; it demonstrates a substantial selectivity for the limbic system. This receptor occupancy profile with relatively higher affinity for the 5HT(2A) receptor compared with the D(2) receptor is in part responsible for the antipsychotic characteristics and low incidence of extrapyramidal side-effects of quetiapine. The efficacy of quetiapine in reducing positive and negative symptoms of schizophrenia has been proven in several clinical trials with placebo-controlled comparators. Quetiapine has also demonstrated robust efficacy for treatment of cognitive, anxious-depressive, and aggressive symptoms in schizophrenia. Long-term trials show sustained tolerability for a broad spectrum of symptoms. Quetiapine has also proven efficacy and tolerability in the treatment of moderate to severe manic episodes, and in the treatment of juveniles with oppositional-defiant or conduct disorders, and in the geriatric dementia population. Recent data indicate that quetiapine may also be effective in the treatment of bipolar depressive symptoms without increasing the risk of triggering manic episodes, and in borderline personality disorder. In comparison with other antipsychotics, quetiapine has a favorable side-effect profile. In clinical trials only small insignificant prolongations of the QT interval were observed. Weight-gain liabilities and new-onset metabolic side-effects occupy a middle-ground among newer antipsychotics. As a result of its good efficacy and tolerability profile quetiapine has become well established in the treatment of schizophrenia and manic episodes.
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PMID:Quetiapine in the treatment of schizophrenia and related disorders. 1930 May 55

Quetiapine is an atypical antipsychotic agent with well established efficacy and tolerability in the acute and maintenance treatment of adults with schizophrenia. The extended-release formulation of quetiapine (quetiapine XR) was developed to provide more convenient once-daily administration, as well as allowing simple and rapid dose escalation, with the aim of improving compliance (known to be a substantial issue in patients with schizophrenia). In several short-term clinical trials, oral quetiapine XR 400-800 mg once daily was generally effective across a range of symptoms in the acute treatment of schizophrenia. As a long-term maintenance treatment, quetiapine XR prevented relapse in patients with stable disease, with significantly longer times to relapse in patients treated with quetiapine XR compared with placebo. Quetiapine XR was generally well tolerated in clinical trials. According to pooled results from three 6-week trials, events occurring in >or=5% of quetiapine XR recipients with an incidence>or=2-fold that seen in placebo recipients were dry mouth, somnolence and dizziness. A generally low incidence of extrapyramidal symptoms (EPS) is seen in quetiapine XR recipients. The most common potentially EPS-associated adverse events seen with quetiapine treatment were akathisia, restlessness and tremor. Rates of worsening of Simpson-Angus Scale and Barnes Akathisia Rating Scale scores were not dissimilar among quetiapine XR, quetiapine immediate release and placebo.
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PMID:Quetiapine extended release: in schizophrenia. 1932 May 34


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