Quetiapine. A review of its use in the management of schizophrenia

Quetiapine (Seroquel), a dibenzothiazepine derivative, is an atypical antipsychotic with demonstrated efficacy in acute schizophrenia. In short-term, randomised, double-blind trials, it was usually more effective than placebo, and was generally effective against both positive and negative symptoms. Overall, quetiapine (up to 750 mg/day) was at least as effective as chlorpromazine (up to 750 mg/day) and had similar efficacy to haloperidol (up to 16 mg/day) in patients with acute schizophrenia in randomised, double-blind trials; it was at least as effective as haloperidol 20 mg/day in patients with schizophrenia unresponsive or partially responsive to previous antipsychotic treatment. Improvements in overall psychopathology and positive and negative symptoms with quetiapine (up to 800 mg/day) were similar to those with risperidone (up to 8 mg/day) or olanzapine (15 mg/day) [interim analysis]. Efficacy was maintained for at least 52 weeks in open-label follow-up studies in adult and elderly patients. Quetiapine improved cognitive function versus haloperidol, and depressive symptoms and hostility/aggression versus placebo. Quetiapine is well tolerated. It is associated with placebo-level incidence of extrapyramidal symptoms (EPS) across its entire dose range, appears to have a low risk for EPS in vulnerable patient groups (e.g. the elderly, adolescents or patients with organic brain disorders) and has a more favourable EPS profile than risperidone. Irrespective of dose, quetiapine, unlike risperidone and amisulpride, does not elevate plasma prolactin levels compared with placebo, and previously elevated levels may even normalise. Quetiapine appears to have minimal short-term effects on bodyweight and a favourable long-term bodyweight profile. Preliminary studies indicate that there is a high level of patient acceptability and satisfaction with quetiapine. In conclusion, quetiapine has shown efficacy against both positive and negative symptoms of schizophrenia, and has benefits in improving cognitive deficits, affective symptoms and aggression/hostility. The beneficial effects of quetiapine have been maintained for at least 52 weeks. Quetiapine was effective and well tolerated in hard-to-treat patients, and may be of particular use in these individuals. It is at least as effective as standard antipsychotics and appears to have similar efficacy to risperidone and olanzapine. The relative risk/benefit profile of quetiapine compared with other atypical antipsychotics requires further research in head-to-head trials, although quetiapine's relatively benign tolerability profile distinguishes it from other commonly used atypical agents, particularly with respect to bodyweight, EPS and plasma prolactin levels. Overall, quetiapine has an excellent risk/benefit profile and is a suitable first-line option for the treatment of schizophrenia.     

Review of quetiapine and its clinical applications in schizophrenia

Preclinical studies have shown that quetiapine (Seroquel, AstraZeneca) is an atypical antipsychotic with many similarities to clozapine. Both placebo-controlled and comparative studies in patients with schizophrenia have demonstrated that quetiapine has long-term efficacy in both positive and negative domains, as well as beneficial effects on affective and cognitive symptoms. Comparative clinical studies confirm that quetiapine is at least as effective as the standard antipsychotics, chlorpromazine and haloperidol and response rates with quetiapine are similar to those reported with other atypical antipychotics. Quetiapine has also demonstrated superior efficacy to haloperidol in partially responsive patients, who can be particularly difficult to treat. Quetiapine has a wide clinical dosing range (150-750 mg/day), although doses of 400 mg or above should be used in patients who do not fully respond to lower doses of the drug. Quetiapine is generally well tolerated with no requirement for routine ECG or blood monitoring and it has minimal effects on weight. Uniquely among other first-line atypical antipsychotics, quetiapine is associated with a placebo-level incidence of EPS and an indistinguishable effect from placebo on plasma prolactin at all doses. Thus, clinicians can confidently increase the dose of quetiapine, without increasing the risk of EPS or hyperprolactinaemia. A number of studies have also shown that quetiapine is well-tolerated and effective in patients who are particularly susceptible to EPS, including elderly and adolescent patients and those with pre-existing dopaminergic pathology, such as Alzheimer's disease and Parkinson's disease. The consistent efficacy in treating all schizophrenic domains and good tolerability, particularly placebo-level EPS, make quetiapine acceptable to patients, as demonstrated in a survey of patient satisfaction. Thus quetiapine is a suitable first-line therapy for the treatment of schizophrenia and psychosis.     

Review of quetiapine and its clinical applications in schizophrenia

Preclinical studies have shown that quetiapine (Seroquel?, AstraZeneca) is an atypical antipsychotic with many similarities to clozapine. Both placebo-controlled and comparative studies in patients with schizophrenia have demonstrated that quetiapine has long-term efficacy in both positive and negative domains, as well as beneficial effects on affective and cognitive symptoms. Comparative clinical studies confirm that quetiapine is at least as effective as the standard antipsychotics, chlorpromazine and haloperidol and response rates with quetiapine are similar to those reported with other atypical antipychotics. Quetiapine has also demonstrated superior efficacy to haloperidol in partially responsive patients, who can be particularly difficult to treat. Quetiapine has a wide clinical dosing range (150 - 750 mg/day), although doses of 400 mg or above should be used in patients who do not fully respond to lower doses of the drug. Quetiapine is generally well tolerated with no requirement for routine ECG or blood monitoring and it has minimal effects on weight. Uniquely among other first-line atypical antipsychotics, quetiapine is associated with a placebo-level incidence of extrapyramidal side-effects (EPS) and an indistinguishable effect from placebo on plasma prolactin at all doses. Thus, clinicians can confidently increase the dose of quetiapine, without increasing the risk of EPS or hyperprolactinaemia. A number of studies have also shown that quetiapine is well-tolerated and effective in patients who are particularly susceptible to EPS, including elderly and adolescent patients and those with pre-existing dopaminergic pathology, such as Alzheimer’s disease and Parkinson’s disease. The consistent efficacy in treating all schizophrenic domains and good tolerability, particularly placebo-level EPS, make quetiapine acceptable to patients, as demonstrated in a survey of patient satisfaction. Thus quetiapine is a suitable first-line therapy for the treatment of schizophrenia and psychosis.     

Quetiapine or haloperidol as monotherapy for bipolar mania--a 12-week, double-blind, randomised, parallel-group, placebo-controlled trial.

METHODS: Patients (n=302) with bipolar I disorder (manic episode) were randomised to 12 weeks' double-blind treatment with quetiapine (flexibly dosed up to 800 mg/day), placebo, or haloperidol (up to 8 mg/day). The primary efficacy outcome variable was change from baseline to Day 21 in Young Mania Rating Scale (YMRS) score. RESULTS: YMRS score improved with quetiapine at Day 21 (-12.29 versus -8.32 for placebo; P<0.01). The difference in favor of quetiapine increased by Day 84 (-17.52 versus -9.48; P<0.001). Haloperidol also showed an advantage over placebo at Days 21 and 84 (P<0.001). There was no significant difference in efficacy measures between quetiapine and haloperidol groups at any assessment except Day 21. The only common adverse event with quetiapine was somnolence (12.7%). Extrapyramidal symptoms (EPS), including akathisia, occurred at 59.6% with haloperidol, 12.7% with quetiapine, 15.8% with placebo. Most quetiapine responders (84%) received a dose of 400-800 mg/day. CONCLUSIONS: Quetiapine was effective and well tolerated. The efficacy and tolerability profile of haloperidol (including its propensity for EPS) supported study validity.     

Combined treatment of quetiapine with haloperidol in animal models of antipsychotic effect and extrapyramidal side effects: comparison with risperidone and chlorpromazine

Rationale Quetiapine, an atypical neuroleptic, has beneficial antipsychotic effects in schizophrenic patients, but with a lower incidence of extrapyramidal symptoms (EPS) compared with typical antipsychotics. While typical antipsychotics are often switched to atypical agents when adverse effects become limiting, there is little preclinical information to support this strategy, both in terms of efficacy and side effects.Objectives The antipsychotic effects and EPS during concomitant administration of quetiapine with haloperidol, a typical antipsychotic agent, were evaluated in mice and compared with chlorpromazine and risperidone.Methods We first investigated the antipsychotic effects and EPS liability of quetiapine, risperidone, chlorpromazine, and haloperidol when administered alone to select optimal doses for subsequent combination studies. The second study was designed to evaluate the antipsychotic efficacy and EPS profile of concomitant administration of quetiapine, risperidone, or chlorpromazine with haloperidol. Antipsychotic effects were evaluated with the methamphetamine-induced hyperlocomotion test, and EPS liability was evaluated in a catalepsy-induction model.Results Quetiapine, risperidone, chlorpromazine, and haloperidol dose-dependently reduced methamphetamine-induced hyperlocomotion, with ED₅₀ values of 5.6, 0.020, 1.8, 0.035 mg/kg, respectively. In the catalepsy test, quetiapine only weakly induced catalepsy at the highest dose of 100 mg/kg, whereas risperidone, chlorpromazine, and haloperidol dose-dependently induced catalepsy with ED₅₀ values of 0.25, 4.6, and 0.10 mg/kg, respectively. While the combination of quetiapine (6 mg/kg) and haloperidol (0.04 mg/kg) significantly reduced methamphetamine-induced hyperlocomotion in comparison with haloperidol alone, quetiapine (10, 32 mg/kg) plus haloperidol did not potentiate the cataleptogenic activity of haloperidol. In contrast, risperidone (0.1, 0.32 mg/kg) or chlorpromazine (3.2 mg/kg) significantly augmented catalepsy induced by haloperidol. Catalepsy induced by co-administration of quetiapine (10 mg/kg) and haloperidol (0.1 mg/kg) was significantly potentiated by WAY100635, a 5-HT_1A antagonist, and catalepsy induced by co-administration of risperidone (0.1 mg/kg) and haloperidol (0.1 mg/kg) was significantly antagonized by 8-OH-DPAT, a 5-HT_1A agonist.Conclusion The present study demonstrated that the combined administration of quetiapine with haloperidol did not aggravate EPS, possibly because of its affinity for 5-HT_1A receptors. This finding may have the clinical implication that quetiapine could provide a successful regimen in switching from typical antipsychotic agents in the symptom management of schizophrenia, or even in adjunctive therapy with other antipsychotic agents.     

The efficacy and tolerability of once-daily extended release quetiapine fumarate in hospitalized patients with acute schizophrenia: a 6-week randomized, double-blind, placebo-controlled study

Objectives: This study aimed to demonstrate efficacy of once-daily extended release quetiapine fumarate (quetiapine XR) versus placebo in patients with acute schizophrenia. Methods: In this 6-week, randomized, double-blind study (5077IL/0041) patients were randomized to receive quetiapine XR (300, 600, or 800 mg/day), quetiapine fumarate immediate release (quetiapine IR) [300 or 600 mg/day], or placebo. Primary endpoint was change from baseline in the Positive and Negative Syndrome Scale (PANSS) total score at Day 42. Secondary variables included PANSS response rate at Day 42 (>/=30% decrease in PANSS total score from baseline) and Clinical Global Impressions Severity (CGI-S) and Improvement (CGI-I) ratings. Safety assessments included adverse event (AE) reporting and laboratory measures. Results: Of 532 patients randomized, 222 (41.7%) completed the study. Improvements in PANSS total scores from baseline to Day 42 across treatment groups were: quetiapine XR 300 mg/day -5.01, 600 mg/day -13.01 and 800 mg/day -11.17, quetiapine IR 300 mg/day -9.42 and 600 mg/day -6.97, and placebo -5.19; the difference in change was statistically significant only for quetiapine XR 600 mg/day (p = 0.033). There were no statistically significant differences between active treatment groups and placebo for PANSS response rates. Several post hoc analyses were conducted to explain the study efficacy outcome but these were inconclusive. Quetiapine XR was generally well tolerated with the majority of AEs being mild or moderate in intensity and no unexpected AEs. Conclusions: Superior efficacy of quetiapine XR versus placebo in patients with schizophrenia was demonstrated for quetiapine XR 600 mg/day. The safety and tolerability profile of quetiapine XR was similar to that of quetiapine IR.     

Quetiapine: a review of its use in the management of bipolar depression

Quetiapine (Seroquel?) is an orally administered atypical antipsychotic that is indicated for the treatment of schizophrenia and bipolar disorder, including bipolar depression. An extended-release (XR) formulation of quetiapine is also available. This review summarizes the pharmacological properties, efficacy and tolerability of quetiapine and quetiapine XR in patients with bipolar depression. Quetiapine is an antagonist at both serotonin 5-HT2 and dopamine D2 receptors, and its antipsychotic effects are thought to stem from interactions at these receptors. The antidepressant effects of quetiapine are poorly understood, but may be related to antagonism of 5-HT2A receptors in cortical regions, partial agonism of 5-HT1A in the prefrontal cortex in association with increased extracellular dopamine release in the region, or to reduced synaptic reuptake of noradrenaline resulting from inhibition of the noradrenaline reuptake transporter by the quetiapine metabolite norquetiapine. The efficacy and tolerability of quetiapine was evaluated in five 8-week, randomized, double-blind, placebo-controlled, multicentre or multinational trials in patients with a major depressive episode (MDE) associated with bipolar disorder. Across trials, monotherapy with oral quetiapine 300 or 600?mg/day (or quetiapine XR 300?mg/day) produced significantly greater improvements than placebo in depressive symptoms (primary endpoint), according to the change in the Montgomery-Asberg Depression Rating Scale total score. In general, quetiapine and quetiapine XR were also associated with significantly higher MDE response and remission rates than placebo. Across trials, quetiapine and quetiapine XR produced significantly greater improvements in global severity of illness scores than placebo, according to changes in the Clinical Global Impressions scale score. There were no differences in treatment outcomes between quetiapine 300?mg/day and 600?mg/day dosage groups. Patients with bipolar depression who responded to quetiapine during two 8-week acute treatment trials also benefited from continuing quetiapine therapy for up to 52 weeks. Compared with quetiapine responders randomized to placebo, quetiapine responders who continued quetiapine 300 or 600?mg/day had a significantly reduced risk of recurrence of any mood events and of depression mood events, but not of hypomanic/manic events. In a randomized, double-blind, placebo-controlled trial, quetiapine maintenance therapy for up to 104 weeks was more efficacious than placebo or lithium in prolonging the time to recurrence of any mood event (primary endpoint). Patients in this trial had bipolar I disorder with mania, depression or a mixed episode as the index episode, and the trial included only patients who were responsive to acute phase quetiapine, which may have introduced a positive bias in favour of quetiapine over lithium during maintenance therapy. Quetiapine 300 or 600?mg/day and quetiapine XR 300?mg/day was generally well tolerated in patients with bipolar depression, with most treatment-emergent adverse events being of mild to moderate severity. The most frequent adverse events occurring during the acute treatment phase were dry mouth, sedation, somnolence, dizziness (quetiapine and quetiapine XR), constipation (quetiapine) and increased appetite (quetiapine XR). Extrapyramidal symptoms (EPS) occurred across quetiapine and placebo groups, but there were no significant differences between quetiapine and placebo recipients on objective measures of EPS and akathisia. In some trials, quetiapine recipients experienced significantly greater weight gain than placebo recipients. Across trials, some quetiapine recipients had clinically relevant increases in blood glucose or lipid parameters, although these also occurred in patients from other treatment groups. The clinical significance of these changes is uncertain. In conclusion, quetiapine and quetiapine XR are valuable additions to the first-line treatments for bipolar depression. Further head-to-head trials of quetiapine versus other drug regimens that are effective in bipolar depression would be of considerable interest.     

A comparison of the effects of quetiapine ('seroquel') and haloperidol in schizophrenic patients with a history of and a demonstrated, partial response to conventional antipsychotic treatment. PRIZE Study Group

Quetiapine ('Seroquel') is a well-tolerated, novel, atypical antipsychotic with consistent efficacy in the treatment of schizophrenia. To date, no clinical studies have evaluated the effect of quetiapine in patients who only partially respond to conventional antipsychotics, yet this type of patient is most frequently seen by psychiatrists. Therefore, this international, multicentre, double-blind study was conducted to compare the efficacy and tolerability of 8 weeks' treatment of quetiapine 600 mg/day with haloperidol 20 mg/day in 288 patients who had a history of partial response to conventional antipsychotics and displayed a partial or no response to 1 month of fluphenazine (20 mg/day) treatment. Patients on quetiapine tended to have greater improvement than those on haloperidol in the primary efficacy measure, mean Positive and Negative Symptom Scale (PANSS) score, after 4 weeks' treatment (-9.05, -5.82, respectively, P = 0.061) and at study end (-11.50, -8.87, respectively, P = 0.234). Similarly, there was a trend towards patients on quetiapine demonstrating greater improvements in the secondary efficacy measures (Clinical Global Impression, PANSS subscale and Brief Psychiatric Rating Scale scores) [week 4 (baseline) to week 12 (end)], but the difference between treatments did not reach significance. Significantly more patients on quetiapine than on haloperidol showed a clinical response-patient response rates, defined as > 20% reduction in PANSS total score between weeks 4 and 12, were 52.2% for quetiapine and 38.0% for haloperidol (P = 0.043). Patients receiving quetiapine required less anticholinergic medication (P < 0.011), had greater reduction in extrapyramidal symptoms (EPS) (P = 0.005) and fewer treatment-emergent EPS-related adverse events compared to those on haloperidol (P < 0.001). Serum prolactin concentrations were elevated at the end of fluphenazine treatment in 73% of patients. Between weeks 4 and 12, elevated serum prolactin concentrations significantly decreased in quetiapine-treated patients compared to those receiving haloperidol (P < 0.001). At the end of quetiapine treatment, 83% of patients had normal prolactin levels while only 21% of patients receiving haloperidol were within the normal range. These results suggest that quetiapine may make a valuable contribution to the management of patients with a history of partial response to conventional antipsychotics.     

Efficacy of quetiapine for the treatment of schizophrenia: a combined analysis of three placebo-controlled trials

OBJECTIVE: To determine the effectiveness of quetiapine (Seroquel) against specific aspects of schizophrenic symptomatology. RESEARCH DESIGN AND METHODS: Combined data from three placebo-controlled, double-blind, randomised trials that had previously demonstrated quetiapine's overall clinical effectiveness and tolerability were analysed. Efficacy assessments evaluated were the Clinical Global Impression (CGI) Severity of Illness score, Brief Psychiatric Rating Scale (BPRS) factors I-V, BPRS positive symptom cluster score and 18 individual BPRS items. The Simpson-Angus Scale (SAS), the Abnormal Involuntary Movements Scale (AIMS), changes in weight and prolactin concentrations and the recording of adverse events comprised the main tolerability measures. RESULTS: Efficacy assessments were available for a total of 426 quetiapine patients (mean age 36.9 years) with a DSM-IIIR diagnosis of schizophrenia; 502 patients were included in the tolerability analyses. The mean quetiapine dose was 300.5 mg/day with a mean maximum dose of 686.0 mg/day. Quetiapine was efficacious across a broad range of symptoms, including depression, anxiety and hostility. Significant improvements compared with placebo were noted for CGI Severity of Illness (p < 0.001) and in 14 of the 18 individual BPRS items (p < 0.001). Positive symptoms also improved (p < 0.01 at Week 2 and p < 0.001 from Week 3); greater improvements were observed in patients who received at least 400 mg/day quetiapine. Quetiapine was generally well tolerated: 4.0% of patients withdrew from treatment due to adverse events compared with 3.0% of placebo patients. Akathisia occurred in 2.0% and 2.5% of quetiapine and placebo patients, respectively. Similar decreases in prolactin levels for quetiapine (-10.0 microg/L) and placebo (-10.9 microg/L) were noted from baseline to end of treatment. Agitation and headache, the most common adverse events, were comparable in the quetiapine and placebo groups (agitation: 19.3% vs. 20.3%, respectively; headache: 19.1% vs. 17.3%, respectively). CONCLUSIONS: The results of this combined analysis confirm the individual findings of the three pivotal studies to demonstrate that quetiapine is effective across several domains of schizophrenia, improving positive, negative and depressive symptoms and reducing agitation, aggression and hostility. Similarly, the analysis reiterated the good tolerability profile of quetiapine, particularly in terms of its placebo-like effects on prolactin levels and incidence of extrapyramidal symptoms (EPS).     

Focus on quetiapine

Quetiapine fumarate is a novel dibenzothiazepine antipsychotic developed by Zeneca. It is marketed under the trade name 'Seroquel'. Quetiapine is well tolerated and clinically effective in the treatment of schizophrenia. The initial hope of investigators was that quetiapine would have antipsychotic potential and that it might share some of the properties of clozapine without its toxicity to white blood cells. The effective dosage range is usually 300-450 mg/day split into two doses. The dose is titrated upwards from 25 mg twice daily from day 1 to 300 mg/day on day 4. Elderly patients or patients with liver problems should be started on lower doses. It is both superior to placebo and comparable to haloperidol in reducing positive symptoms at doses ranging from 150 mg/day to 750 mg/day, and is an effective treatment for negative symptoms. Somnolence is the most common adverse event. Abnormalities of the QT interval on ECG appear very infrequently and there is no need for a baseline ECG or blood pressure monitoring, as used to be the case with sertindole. There is no need for haematological monitoring as with clozapine. Quetiapine, across the full dosage range, is associated with no greater extrapyramidal symptoms than placebo. Quetiapine's general efficacy and side-effect profile suggest that, unless there are unforeseen post-marketing complications, it deserves a major place in the initial and long-term management of schizophreniform disorders.     

Efficacy of quetiapine for the treatment of schizophrenia: a combined analysis of three placebo-controlled trials

SUMMARY

Objective: To determine the effectiveness of quetiapine (Seroquel*) against specific aspects of schizophrenic symptomatology.

Research design and methods: Combined data from three placebo-controlled, double-blind, randomised trials that had previously demonstrated quetiapine’s overall clinical effectiveness and tolerability were analysed. Efficacy assessments evaluated were the Clinical Global Impression (CGI) Severity of Illness score, Brief Psychiatric Rating Scale (BPRS) factors I–V, BPRS positive symptom cluster score and 18 individual BPRS items. The Simpson–Angus Scale (SAS), the Abnormal Involuntary Movements Scale (AIMS), changes in weight and prolactin concentrations and the recording of adverse events comprised the main tolerability measures.

Results: Efficacy assessments were available for a total of 426 quetiapine patients (mean age 36.9 years) with a DSM-IIIR diagnosis of schizophrenia; 502 patients were included in the tolerability analyses. The mean quetiapine dose was 300.5?mg/day with a mean maximum dose of 686.0?mg/day. Quetiapine was efficacious across a broad range of symptoms, including depression, anxiety and hostility. Significant improvements compared with placebo were noted for CGI Severity of Illness (?p < 0.001) and in 14 of the 18 individual BPRS items (?p < 0.001). Positive symptoms also improved (?p < 0.01 at Week 2 and p < 0.001 from Week 3); greater improvements were observed in patients who received at least 400?mg/day quetiapine. Quetiapine was generally well tolerated: 4.0% of patients withdrew from treatment due to adverse events compared with 3.0% of placebo patients. Akathisia occurred in 2.0% and 2.5% of quetiapine and placebo patients, respectively. Similar decreases in prolactin levels for quetiapine (–10.0?µg/L) and placebo (–10.9?µg/L) were noted from baseline to end of treatment. Agitation and headache, the most common adverse events, were comparable in the quetiapine and placebo groups (agitation: 19.3% vs. 20.3%, respectively; headache: 19.1% vs. 17.3%, respectively).

Conclusions: The results of this combined analysis confirm the individual findings of the three pivotal studies to demonstrate that quetiapine is effective across several domains of schizophrenia, improving positive, negative and depressive symptoms and reducing agitation, aggression and hostility. Similarly, the analysis reiterated the good tolerability profile of quetiapine, particularly in terms of its placebo-like effects on prolactin levels and incidence of extrapyramidal symptoms (EPS).     

Aripiprazole: a review of its use in schizophrenia and schizoaffective disorder

Aripiprazole, a quinolinone derivative, is an atypical antipsychotic drug indicated for the treatment of adult patients with schizophrenia. Aripiprazole 10 or 15 mg once daily is effective and well tolerated in patients with schizophrenia or schizoaffective disorder. Although aripiprazole has only been directly compared with haloperidol and olanzapine in treatment-responsive patients to date, current data generally indicate that aripiprazole has a beneficial profile in terms of a low potential for bodyweight gain. Dosage titration is not necessary and the drug is effective in the first few weeks of treatment. Head-to-head comparative trials with atypical antipsychotic agents are required, as are long-term (> or =1 year) studies, to fully define the position of aripiprazole in relation to other antipsychotic drugs. Aripiprazole is a valuable new therapeutic option in the management of patients with schizophrenia. PHARMACOLOGICAL PROPERTIES: Aripiprazole is a quinolinone derivative with a high affinity for dopamine D2 and D3 receptors, and serotonin 5-HT1A, 5-HT2A and 5-HT2B receptors. The mechanism of action of aripiprazole is not yet known, but evidence suggests that its efficacy in the treatment of the positive and negative symptoms of schizophrenia and its lower propensity for extrapyramidal symptoms (EPS) may be attributable to aripiprazole's partial agonist activity at dopamine D2 receptors. At serotonin 5-HT1A receptors, in vitro studies have shown that aripiprazole acts as a partial agonist whereas at serotonin 5-HT2A receptors aripiprazole is an antagonist. The main active metabolite, dehydro-aripiprazole, has affinity for dopamine D2 receptors and thus has some pharmacological activity similar to that of the parent compound. Aripiprazole is rapidly absorbed after oral administration. The mean time to peak plasma concentration is 3 hours following multiple-dose administration of aripiprazole 10 or 15 mg and the absolute oral bioavailability of the drug is 87%. Steady-state plasma drug concentrations are achieved by 14 days; however, the drug appears to accumulate over this period, since mean peak plasma concentration and mean area under the plasma concentration-time curve values of aripiprazole 10 or 15 mg/day are 4-fold greater on day 14 than on day 1. This accumulation may be expected, since the mean elimination half-life of a single dose of aripiprazole is about 75 hours. Aripiprazole has extensive extravascular distribution and more than 99% of aripiprazole and dehydro-aripiprazole (the main active metabolite of aripiprazole) is bound to plasma protein. Elimination of the drug is primarily hepatic; the cytochrome P450 (CYP) 3A4 and CYP2D6 enzyme systems transform aripiprazole to dehydro-aripiprazole, with the latter enzyme system subject to genetic polymorphism. Thus, dosage adjustment of aripiprazole is necessary when it is coadministered with CYP3A4 and CYP2D6 inhibitors (since aripiprazole concentration is increased) and with inducers of CYP3A4 (since aripiprazole concentration is decreased). THERAPEUTIC EFFICACY: The efficacy of aripiprazole has been demonstrated in patients with schizophrenia or schizoaffective disorder. In general, significant reductions from baseline in mean Positive and Negative Syndrome Scale total, positive and negative symptom scores, and Clinical Global Impression Severity of Illness scores were observed in patients with acute relapse of chronic schizophrenia or schizoaffective disorder receiving recommended (10 or 15 mg/day) or higher-than-recommended (20 or 30 mg/day) dosages of aripiprazole versus those receiving placebo in three well controlled, short-term trials. No additional therapeutic benefit was observed at the higher-than-recommended dosages. The drug is effective as early as the first or second week of treatment. The efficacy of aripiprazole was maintained for up to 52 weeks. The drug was significantly more effective than placebo in preventing relapse in patients with stable chronic schizophrenia in a 26-week, randomised trial. In a 52-week trial in patients with acute relapse of schizophrenia, the percentage of responders maintaining a response at study end was 77% of aripiprazole versus 73% of haloperidol recipients. Aripiprazole may improve cognitive function. In a nonblind, 26-week trial, patients with chronic schizophrenia receiving aripiprazole 30 mg/day experienced similar (general cognitive function) or better (verbal learning) changes from baseline in the neurocognitive parameters evaluated compared with recipients of olanzapine 10-15 mg/day. TOLERABILITY: Aripiprazole 10-30 mg/day was generally well tolerated. The tolerability profile of aripiprazole was broadly similar to that observed with placebo in a meta-analysis of short-term trials in patients with acute relapse of schizophrenia or schizoaffective disorder and in a 26-week trial in patients with chronic stable schizophrenia. The most frequent treatment-emergent adverse events included insomnia and anxiety, and additionally, headache and agitation (in short-term trials) or akathisia and psychosis (in a 52-week trial). In general, the drug was associated with a placebo-level incidence of EPS and EPS-related adverse events. Significantly fewer aripiprazole recipients experienced EPS-related adverse events than haloperidol recipients in a 52-week trial. Changes in severity of EPS were minimal and usually no different from those observed with placebo. Moreover, there was less severe EPS in the aripiprazole group than the haloperidol group in a long-term trial. Treatment-emergent tardive dyskinesia was reported in only 0.2% of patients receiving aripiprazole (short-term trials), an incidence similar to that seen in placebo recipients (0.2%). Aripiprazole has a low propensity to cause clinically significant bodyweight gain, hyperprolactinaemia or corrected QT interval prolongation in patients with schizophrenia or schizoaffective disorder. In addition, there were no clinically relevant differences in mean changes from baseline in measures of diabetes and dyslipidaemia between the aripiprazole or placebo groups in a 26-week, placebo-controlled trial.     

Managing acute exacerbations of schizophrenia: focus on quetiapine

In this commentary article we describe our clinical experience and provide our views on the use of quetiapine in the treatment of patients with acute exacerbations of schizophrenia. Some patients with acute schizophrenia may require parenteral medication; however, we believe that oral antipsychotics, either alone or in combination with other medications, have a key role to play as an initial and/or subsequent pharmacotherapeutic intervention. Quetiapine has beneficial calming properties and successfully treats the symptoms of aggression, anxiety and hostility that can accompany acute exacerbations of schizophrenia. Based upon a review of published findings, data presented at recent international psychiatric congresses and our clinical experience, we propose that a more rapid initiation schedule (for example, 400 mg by Day 2, increasing to 600 mg/day by Day 3 and often up to 800 mg/day by Day 4, or in severe cases 300 mg on Day 1, 600 mg on Day 2 and 900 mg on Day 3) than that currently described in quetiapine prescribing information can be used to provide safe, effective treatment in hospitalised patients with acute schizophrenia. (Note that lower doses are used in patients with first-episode schizophrenia.) Furthermore, while current prescribing information recommends that quetiapine be administered at doses up to 750 mg/day (800 mg/day in the USA and Canada), there is growing evidence that dosing up to 1600 mg/day of quetiapine has been well tolerated in some patients. In general, newer antipsychotics have superior tolerability profiles compared with conventional agents; however, clear differences in tolerability exist among the new generation antipsychotics. Quetiapine has an excellent tolerability profile offering high patient acceptability that, in turn, may promote patient adherence to medication and an improved quality of life. As such, we consider quetiapine to be a first-choice antipsychotic for the treatment of acute exacerbations of schizophrenia.     

Efficacy of extended release quetiapine fumarate monotherapy in patients with major depressive disorder: a pooled analysis of two 6-week, double-blind, placebo-controlled studies

Prospectively planned pooled analysis evaluating the efficacy of quetiapine extended release (XR) monotherapy in major depressive disorder (MDD). Data were pooled from two 6-week, randomized, double-blind, placebo-controlled studies of quetiapine XR in outpatients with MDD. The primary endpoint was Montgomery-?sberg Depression Rating Scale (MADRS) total score change from randomization at week 6. Other evaluations were MADRS response/remission, Hamilton Rating Scale for Anxiety, and subgroup analyses. A total of 968 patients were randomized to quetiapine XR, 150 mg/day (n=315), 300 mg/day (n=323), or placebo (n=330). The mean MADRS total score reductions from randomization were significant at week 6 with quetiapine XR, 150 mg/day (-14.7; P<0.001) and 300 mg/day (-14.7; P<0.001) versus placebo (-11.1), with significant reductions versus placebo from week 1 onward. Response rates (week 6): 52.7% (P<0.001) quetiapine XR 150 mg/day and 49.5% (P<0.001) quetiapine XR 300 mg/day versus placebo (33.0%). MADRS remission (score≤8; week 6): 23.5% (P=0.208) quetiapine XR 150 mg/day and 28.8% (P<0.01) quetiapine XR 300 mg/day versus placebo (19.4%). Quetiapine XR (both doses) significantly improved eight of 10 MADRS items versus placebo at week 6. The therapeutic effect of quetiapine XR was neither limited to nor driven by factors such as sex, age, or severity of depression. In patients with MDD, quetiapine XR (150 and 300 mg/day) monotherapy reduced depressive symptoms, with significant improvements compared with placebo from week 1 onward.     

Quetiapine: dose-response relationship in schizophrenia

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.     

Managing acute exacerbations of schizophrenia: focus on quetiapine

SUMMARY

In this commentary article we describe our clinical experience and provide our views on the use of quetiapine in the treatment of patients with acute exacerbations of schizophrenia. Some patients with acute schizophrenia may require parenteral medication; however, we believe that oral antipsychotics, either alone or in combination with other medications, have a key role to play as an initial and/or subsequent pharmacotherapeutic intervention. Quetiapine has beneficial calming properties and successfully treats the symptoms of aggression, anxiety and hostility that can accompany acute exacerbations of schizophrenia. Based upon a review of published findings, data presented at recent international psychiatric congresses and our clinical experience, we propose that a more rapid initiation schedule (for example, 400?mg by Day 2, increasing to 600mg/day by Day 3 and often up to 800mg/day by Day 4, or in severe cases 300?mg on Day 1, 600?mg on Day 2 and 900?mg on Day 3) than that

currently described in quetiapine prescribing information can be used to provide safe, effective treatment in hospitalised patients with acute schizophrenia. (Note that lower doses are used in patients with first-episode schizophrenia.) Furthermore, while current prescribing information recommends that quetiapine be administered at doses up to 750mg/day (800mg/day in the USA and Canada), there is growing evidence that dosing up to 1600mg/day of quetiapine has been well tolerated in some patients. In general, newer antipsychotics have superior tolerability profiles compared with conventional agents; however, clear differences in tolerability exist among the new generation antipsychotics. Quetiapine has an excellent tolerability profile offering high patient acceptability that, in turn, may promote patient adherence to medication and an improved quality of life. As such, we consider quetiapine to be a first-choice antipsychotic for the treatment of acute exacerbations of schizophrenia.     

Effects of quetiapine and haloperidol on prepulse inhibition of the acoustic startle (eyeblink) response and the N1/P2 auditory evoked response in man

Contraction of the orbicularis oculi muscle in response to a sudden loud sound (acoustic startle response) and the N1/P2 component of the auditory evoked potential are both attenuated when a brief low-intensity stimulus is presented 30-500 ms before the 'startle-eliciting' stimulus (PPI). Here, we report the effects of the 'atypical' antipsychotic drug quetiapine and the 'conventional' antipsychotic haloperidol on these responses. Sixteen males (aged 19-38 years) participated in four sessions at 7-day intervals, in which they received quetiapine 12.5 mg, quetiapine 25 mg, haloperidol 3 mg and placebo, according to a balanced double-blind design. Electromyographic (EMG) responses of the orbicularis oculi muscle and N1/P2 auditory evoked potentials were recorded in a 20-min session, 2 h after treatment. Subjects received 40 trials in which 1-kHz sounds were presented: (i) 40 ms, 115 dB ('pulse alone' trials) and (ii) 40 ms, 85 dB, followed after 120 ms by 40 ms, 115 dB ('prepulse/pulse' trials). Mean amplitudes of the EMG response and the N1/P2 potential were derived from the pulse-alone trials and, in each case, percentage PPI was calculated. Serum prolactin was measured after each treatment, and autonomic (heart rate, blood pressure, salivation) and psychological (visual analogue self-ratings of mood and alertness, critical flicker fusion frequency) measures were taken before and after each treatment. Quetiapine 12.5 mg and 25 mg significantly reduced the amplitude of the EMG response without altering its inhibition by prepulses; haloperidol had no effect on EMG response amplitude or PPI. Neither drug affected N1/P2 amplitude or PPI of this response. Quetiapine, but not haloperidol, reduced subjective alertness and critical flicker fusion frequency. Haloperidol, but not quetiapine, elevated serum prolactin level. The ability of quetiapine to attenuate the startle response may reflect its sedative action.     

Extended release quetiapine fumarate (quetiapine XR) monotherapy as maintenance treatment for generalized anxiety disorder: a long-term, randomized, placebo-controlled trial

The objective of this study was to evaluate the efficacy and tolerability of extended release quetiapine fumarate (quetiapine XR) as maintenance monotherapy for patients with generalized anxiety disorder (GAD). Time-to-event (anxiety symptom recurrence; maximum 52 weeks) multicenter, randomized-withdrawal, parallel-group, double-blind, placebo-controlled study of quetiapine XR (50-300 mg/day) following open-label run-in (4-8 weeks) and open-label stabilization (≥ 12 weeks). Primary variable: time from randomization to anxiety event. Secondary variables included: Hamilton Anxiety Rating Scale (HAM-A) total, HAM-A psychic/somatic anxiety factors, Clinical Global Impression-Severity of Illness (CGI-S), and Quality of Life, Enjoyment and Satisfaction Questionnaire (Q-LES-Q) scores; adverse events (AE) reporting. Four hundred and thirty-two patients, stabilized on quetiapine XR, were randomized to continue quetiapine XR (N=216) or switch to placebo (N=216). Risk of anxiety symptom recurrence was significantly reduced by 81% for quetiapine XR versus placebo: hazard ratio=0.19 (95% confidence interval 0.12-0.31; P<0.001). Fewer patients receiving quetiapine XR (N=22, 10.2%) than placebo (N=84, 38.9%) experienced anxiety symptom recurrence. Significant differences were observed between quetiapine XR and placebo in: HAM-A total, psychic/somatic, CGI-S (all P<0.001) and Q-LES-Q (P<0.05) scores. AEs (>10%) during open-label treatment were dry mouth, sedation, somnolence, dizziness, fatigue, and constipation. During randomized treatment, the most common AEs for quetiapine XR were headache and nasopharyngitis. Quetiapine XR monotherapy reduced the risk of anxiety symptom recurrence in patients with GAD stabilized on quetiapine XR, with tolerability results consistent with the known profile of quetiapine.     

Differential effect of quetiapine on depressive symptoms in patients with partially responsive schizophrenia

While atypical antipsychotics appear to be effective in reducing depressive symptoms in the acute phase of schizophrenia, little is known about their efficacy in patients with ongoing symptoms. The present study assessed whether quetiapine (Seroquel) is more effective than haloperidol in treating depressive symptoms in patients with persistent positive symptoms, and investigated whether this effect is independent, or secondary to, reductions in other symptoms such as positive, negative or extrapyramidal symptoms. Patients with schizophrenia and a history of partial refractoriness to conventional antipsychotics who had not responded to 4 weeks of fluphenazine treatment (20 mg/day) were randomized to receive either quetiapine (600 mg/day) or haloperidol (20 mg/day) for a further 8 weeks. Change in the Positive and Negative Syndrome Scale depression factor score from baseline to endpoint was calculated and path analyses were performed on data from 269 patients. Quetiapine produced a greater reduction in depressive scores than haloperidol (-1.60 versus -0.54; p = 0.006). The path analyses indicated that this was a direct effect on depressive symptoms. These findings extend the evidence for an antidepressant effect for the novel antipsychotics in schizophrenia, and suggest that this is not limited to acutely psychotic patients.     

Quetiapine for acute mania in bipolar disorder.

PURPOSE: The efficacy and tolerability of quetiapine in the treatment of acute mania were reviewed. SUMMARY: Five randomized, placebo-controlled trials involving quetiapine as monotherapy or adjunct therapy in combination with either divalproex or lithium in the treatment of bipolar mania in either adolescents or adults were identified and reviewed. The primary outcome measure used in the trials was a change in Young Mania Rating Scale total scores. Monotherapy trials evaluated quetiapine, lithium, haloperidol, and placebo. Quetiapine was superior to placebo in both trials. Quetiapine and lithium showed comparable efficacy in one study, though lithium serum concentrations may have been suboptimal. Haloperidol was superior to quetiapine in efficacy at day 21 but similar at day 84. In the two trials evaluating quetiapine or placebo as adjunct therapy to lithium or divalproex, quetiapine was significantly more efficacious than placebo in one trial. In adolescents, quetiapine was more effective than placebo as an adjunct to divalproex. The most common adverse effects clearly attributable to quetiapine in these trials were somnolence and dry mouth. Quetiapine did not induce extrapyramidal effects, but weight gain was notable with the drug. CONCLUSION: While quetiapine treatment demonstrated efficacy in the majority of the studies, the robustness of its efficacy is questionable. The use of quetiapine as first-line therapy for acute mania is not recommended based on the available results and cost considerations. However, it may be a useful second-line agent, particularly when sensitivity to extrapyramidal symptoms limits treatment options.