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

Delusional disorder, somatic type treated with aripiprazole--mirtazapine combination

Delusional disorder, somatic type (DDST) is a rare psychiatric disorder and the treatment is mostly based on observations, due to the lack of well-organized studies. Initially, antipsychotics and especially pimozide were considered to be the pharmacological approach of choice but, subsequently, tryciclic anti-depressants and selective serotonin re-uptake inhibitors (SSRIs) were also suggested to be effective, implicating the serotonergic system in the pathophysiology of the disorder. We present the case of a female with DDST, who responded to aripiprazole-mirtazapine combination, a finding that is in accordance with the initial approach of this disorder as a part of the schizophrenic spectrum, but also supports the hypothesis of serotonin dysfunction in DDST.

The safety of the electroconvulsive therapy-aripiprazole combination: four case reports

In clinical practice, a proportion of patients with psychotic or mood disorders are treated with electroconvulsive therapy (ECT) while receiving concomitantly antipsychotic and/or other psychotropic agents. Aripiprazole is a second-generation antipsychotic that seems to have a favorable side-effect profile. However, to the best of our knowledge, there are, as yet, no available reports on the safety of ECT-aripiprazole combination. We report the cases of 4 female inpatients--3 suffering from major depression and 1 from schizophrenia--who underwent ECT--1 of them twice--while receiving aripiprazole (10-15 mg/d), as part of their regimen. In all cases, the combination was well tolerated and only minimal side effects were reported.

Aripiprazole in the treatment of depressive and anxiety disorders: a review of current evidence

Despite the availability of different classes of drugs for the treatment of depressive and anxiety disorders, there are a number of clinically significant unmet needs, such as a high prevalence of treatment resistance, partial response, subsyndromal symptomatology, recurrence and relapse. With the approval of atypical antipsychotics, which are associated with a lower adverse effect burden than typical antipsychotics, consideration of their off-label use for the treatment of affective disorders and various other psychiatric disorders has become a viable option. However, consideration should be given to the US FDA black box warning indicating that atypical antipsychotics may increase mortality risk, particularly in the elderly population with dementia-related psychosis. There has been much conjecture about the utility of these atypical drugs to facilitate traditional antidepressant therapy, either in combination (from the initiation of therapy) or as adjunctive therapy (in the case of partial/incomplete response). Nevertheless, at present, available evidence from randomized, placebo-controlled trials is sparse, and a formal risk/benefit assessment of the use of these agents in a nonpsychotic patient population is not yet possible. As a representative agent from the atypical antipsychotic class with a novel mechanism of action and a relatively low adverse effect burden, aripiprazole represents an interesting potential treatment for depressive and anxiety disorders. In this review, we focus on the rationale for the use of aripiprazole in these disorders. Preclinical data suggests that aripiprazole has a number of possible mechanisms of action that may be important in the treatment of depressive and anxiety disorders. Such mechanisms include aripiprazole action at serotonin (5-HT) receptors as a 5-HT1A partial receptor agonist, a 5-HT2C partial receptor agonist and a 5-HT2A receptor antagonist. Aripiprazole also acts as a dopamine D2 partial receptor agonist, and has a possible action at adrenergic receptors. Furthermore, aripiprazole may have possible neuroprotective effects. Clinical studies demonstrate that aripiprazole may be useful in the treatment of bipolar depression, major depressive disorder, treatment-resistant depression and possibly anxiety disorders. Clinical data also suggest that aripiprazole may have a lower adverse effect burden than the other atypical drugs. Future research may confirm the potential utility of aripiprazole in the treatment of depressive and anxiety disorders.

Intramuscular aripiprazole : a review of its use in the management of agitation in schizophrenia and bipolar I disorder

An intramuscular formulation of the atypical antipsychotic aripiprazole (Abilify) has been developed and is approved in the EU for use in agitation and disturbed behaviour associated with schizophrenia. In the US, it is approved for the treatment of agitation associated with schizophrenia or bipolar I disorder (manic or mixed). In large, well designed trials, intramuscular aripiprazole was an effective and generally well tolerated treatment for agitation associated with schizophrenia, schizoaffective disorder, schizophreniform disorder or bipolar I disorder. Intramuscular aripiprazole was more effective than placebo in these patient populations and was noninferior to intramuscular haloperidol in those with agitation associated with schizophrenia and its related disorders. Aripiprazole is associated with a low risk for extrapyramidal symptoms (EPS), cardiac effects, hyperprolactinaemia, weight gain and other metabolic disturbances. Head-to-head trials comparing intramuscular aripiprazole with other intramuscular atypical antipsychotics are required before the relative position of each of these agents can be fully determined. In the meantime, intramuscular aripiprazole, with its favourable tolerability profile, is a valuable treatment option for agitation in patients with schizophrenia, schizoaffective disorder, schizophreniform disorder or bipolar I disorder.

The prescribing pattern of a new antipsychotic: a descriptive study of aripiprazole for psychiatric in-patients

In June 2004, aripiprazole was marketed as a second-generation antipsychotic with an entire new mechanism of action. The objective of this descriptive study is to examine the day-to-day prescriptions of aripiprazole to an unselected population of psychiatric in-patients. From 1 February to 1 May 2006, present and former in-patients treated with aripiprazole were identified. Prescriptions of aripiprazole and psychoactive comedication were collected retrospectively from the patient records. Seventy-one patients, mainly schizophrenic, received aripiprazole 2.5 to 55 mg/day for median 350 days. The median average exposure was 18.9 mg/day (range 2.5-45 mg/day) and exceeded 15 and 30 mg/day in 63% and 4.2% of the patients, respectively. Generally, aripiprazole was either added to the existing antipsychotic treatment or replaced other antipsychotics; only 17% of the patients were treatment-naïve. In 25% aripiprazole, monotherapy was commenced whereas aripiprazole-antipsychotic combinations were initially prescribed in 75%. Overall, 85% of the patients received periods of antipsychotic polypharmacy and aripiprazole was combined with 17 different antipsychotics. Each patient received median three (range 0-8) psychoactive drugs parallel with aripiprazole. This study demonstrates reality in psychopharmacology and quote aripiprazole as example. In day-to-day practice, aripiprazole is used as part of highly individualized regimens comprising polypharmacy and excessive dosing. Although theoretically appropriate for some patients, this approach also implies conducting unblinded and uncontrolled mini-experiments. Sparse evidence supports this practice and effectiveness studies of aripiprazole that takes into account the true complexity of clinical prescribing are urgently needed.

Aripiprazole: in adolescents with schizophrenia

Aripiprazole is a novel atypical antipsychotic that is approved in the US for use in adolescents with schizophrenia. In adolescents with schizophrenia, oral aripiprazole 10 or 30 mg/day lead to significantly greater reductions than placebo in the Positive and Negative Syndrome Scale (PANSS) total score from baseline to 6 weeks, according to findings from a randomized, double-blind, multicenter trial (n = 302). In addition, aripiprazole 10 or 30 mg/day recipients had significantly greater improvements in the PANSS positive subscale and Clinical global Impression-Severity and -Improvement scale scores than placebo recipients, and a significantly greater improvement in the PANSS negative subscale score was seen with aripiprazole 10 mg/day than with placebo. Aripiprazole was generally well tolerated in adolescents with schizophrenia, with most adverse events being of mild to moderate severity. Clinically significant weight gain (> or = 7% as defined by the US FDA) occurred in 4.0% of aripiprazole 10 mg/day recipients, 5.2% of aripiprazole 30 mg/day recipients, and 1% of placebo recipients. The mean weight change was significantly different in aripiprazole and placebo recipients (0, +2, and -0.8 kg in aripiprazole 10 mg/day, aripiprazole 30 mg/day, and placebo recipients, respectively).

Iloperidone: a new benzisoxazole atypical antipsychotic drug. Is it novel enough to impact the crowded atypical antipsychotic market?

Iloperidone is a new-generation atypical antipsychotic agent, acting as a serotonin/dopamine (5-HT(2A)/D(2)) antagonist, under development by Vanda Pharmaceuticals for the treatment of schizophrenia, bipolar disorder and other psychiatric conditions. Chemically, iloperidone is a benzisoxazole, like risperidone, and shows a multiple receptor binding profile, sharing this feature with the other atypical antipsychotic agents. Administered orally, the drug is highly bound to plasma proteins and extensively metabolised. Several clinical trials have been carried out, to check efficacy, safety and side effects. In order to introduce iloperidone as an agent for the treatment of schizophrenia, a short overview of the disease and of the most important antipsychotic drugs available or under development will be reported. Iloperidone pharmacokinetics and pharmacodynamics are presented herein, together with an evaluation of clinical safety and efficacy results.

A prospective 6-month analysis of the naturalistic use of aripiprazole - factors predicting favourable outcome

OBJECTIVE

To evaluate the effectiveness of aripiprazole in clinical practice.

METHOD

Prospective follow-up of patients consecutively prescribed aripiprazole in an acute mental health unit. Retrospective analysis of outcome from casenotes.

RESULTS

Data were available on 228 patients. Fifty-one per cent discontinued aripiprazole over 6-month follow-up. Continuation with treatment was more likely in out-patients [relative risk (RR) 1.50; 95% CI: 1.13-2.00], those never before considered for clozapine treatment (RR 1.61, 95% CI: 1.06-2.44) and older patients [RR 1.05, 95% CI: 1.01-1.09 (per 5-year increase)]. The main reason for early discontinuation was the occurrence of minor adverse effects.

CONCLUSION

Aripiprazole is effective in practice. Outcome is likely to be improved by careful patient selection and by attending to adverse effects experienced early in treatment.

Pharmacogenetics of antipsychotic adverse effects: Case studies and a literature review for clinicians

There is a growing body of literature supporting the contribution of genetic variability to the mechanisms responsible for the adverse effects of antipsychotic medications particularly movement disorders and weight gain. Despite the current gap between research studies and the practical tools available to the clinician to identify such risks, it is hoped that in the foreseeable future, pharmacogenetics will become a critical aid to guide the development of personalized therapeutic regimes with fewer adverse effects. We provide a summary of two cases that are examples of using cytochrome P450 pharmacogenetics in an attempt to guide treatment in the context of recent literature concerning the role of pharmacogenetics in the manifestation of adverse effects of antipsychotic therapies. These examples and the review of recent literature on pharmacogenetics of antipsychotic adverse effects illustrate the potential for applying the principles of predictive, preventive, and personalized medicine to the therapy of psychotic disorders.

Detection and quantification of aripiprazole and its metabolite, dehydroaripiprazole, by gas chromatography–mass spectrometry in blood samples of psychiatric patients

Aripiprazole is a novel antipsychotic drug for the treatment of schizophrenia and schizoaffective disorders. In this study, a new method using gas chromatography-mass spectrometry (GC-MS) was developed and validated for the detection of aripiprazole and its main metabolite, dehydroaripiprazole, in plasma. Blood samples from seven psychiatric patients treated with aripiprazole (10-20 mg/day) underwent a solid-phase extraction (SPE) and N-methyl-N-trimethylsilytrifluoroacetamide (MSTFA) derivatization. The characteristic ions of mass spectra for aripiprazole and dehydroaripiprazole were m/z 306, 292, 218 and 304, 290, 218, respectively. Extraction recoveries from this method were 75.4% (n=5) for aripiprazole and 102.3% (n=5) for dehydroaripiprazole. The calibration curves of aripiprazole and dehydroaripiprazole were linear from 16 to 500 ng/ml (r(2)=0.999) and 8 to 250 ng/ml (r(2)=0.999), respectively. The respective limits of quantification (LOQs) for aripiprazole and dehydroaripiprazole evaluated in 0.5 ml of serum were 14.4 ng/ml and 6.9 ng/ml. Intra-assay and interassay precision and accuracy were within acceptable ranges. In this study, we also found that the mean trough concentrations in plasma at steady-state were 128.9 microg/l for aripiprazole and 30.1 microg/l for dehydroaripiprazole.

Efficacy and safety of oral aripiprazole compared with haloperidol in patients transitioning from acute treatment with intramuscular formulations

OBJECTIVE

To report efficacy and safety of transitioning patients receiving intramuscular (IM) formulations of aripiprazole or haloperidol to their respective oral formulations.

METHODS

448 agitated patients with schizophrenia (73%) or schizoaffective disorder (27%) were randomized to receive aripiprazole IM 9.75 mg, haloperidol IM 6.5 mg, or placebo IM within 24 hours. Patients treated with aripiprazole IM or haloperidol IM who completed this 24-hour IM phase were transitioned to the respective blinded oral formulations for 4 days (aripiprazole 10-15 mg/day, n = 153; haloperidol 7.5-10 mg/day, n = 151). Patients treated with placebo IM were transitioned to oral aripiprazole (analysis not included). The primary efficacy measure was mean change in Positive and Negative Syndrome Scale-Excited Component (PEC) score from baseline of oral phase (last value from 24-hour IM phase) to endpoint (study day 5, last observation carried forward).

RESULTS

During the oral phase, aripiprazole 15 mg and haloperidol 10 mg were both effective in maintaining responses achieved on all efficacy measures during the 24-hour IM phase. Mean improvements in PEC scores from study day 1 to 5 were -1.37 for aripiprazole and -1.40 for haloperidol (p = NS for aripiprazole versus haloperidol). Oral aripiprazole was well tolerated. Extrapyramidal symptom-related adverse events were lower for aripiprazole (1.3%) than haloperidol (8.0%). Nausea and vomiting occurred more frequently in patients receiving aripiprazole (3.9% and 2.6%, respectively) than in those receiving haloperidol (0.7% and 1.3%, respectively).

CONCLUSIONS

Acutely agitated patients with schizophrenia or schizoaffective disorder treated with aripiprazole IM or haloperidol IM demonstrated similar effective and safe transition to their respective oral formulations. Initial benefits of reduced agitation and improved clinical status during the IM phase of the study were maintained throughout the oral phase of the study with good tolerability.

Aripiprazole augmentation in the management of residual symptoms in clozapine-treated outpatients with chronic schizophrenia: An open-label pilot study

OBJECTIVE

The aim of this study was to investigate whether augmentation of clozapine with aripiprazole improves clinically significant residual symptoms in stabilized outpatients with chronic schizophrenia.

METHODS

Twenty seven stabilized outpatients meeting criteria for chronic schizophrenia, who had residual symptoms despite clozapine treatment, were assigned to receive oral aripiprazole (15 mg/day) for a period of 16 weeks. Patients remained on clozapine (100-900 mg/day) for at least 12 months, prior to study initiation. Symptoms assessments were made with the Positive and Negative Symptom Scale (PANSS), the Montgomery-Asberg Depression Rating Scale (MADRS), and the Mini-Mental State Examination (MMSE), at baseline and at weeks 4, 8, 12, and 16. The Quality of Life Scale (QLS) was administered at baseline and at week 16.

RESULTS

There was a statistically significant improvement in the mean scores for PANSS (p<0.05), PANSS negative (p<0.001), MADRS (p<0.05), MMSE (p<0.01), and QLS (p<0.05), but not for PANSS positive (p>0.05). Extrapyramidal side effects (as assessed by the Simpson-Angus Scale and the Abnormal Involuntary Movement Scale) did not vary significantly at any point of the study. No statistically significant change was observed in prolactin levels and body weight. Results were similar for the intention-to-treat (n=27) and completer (n=23) groups.

CONCLUSIONS

Aripiprazole augmentation in a group of chronic schizophrenic outpatients treated with clozapine led to a substantial improvement in clinically significant residual symptoms, such as negative-depressive symptoms, cognitive impairment and quality of life, without worsening the side effect burden.

Metabolic drug interactions with newer antipsychotics: a comparative review

Newer antipsychotics introduced in clinical practice in recent years include clozapine, risperidone, olanzapine, quetiapine, sertindole, ziprasidone, aripiprazole and amisulpride. These agents are subject to drug-drug interactions with other psychotropic agents or with medications used in the treatment of concomitant physical illnesses. Most pharmacokinetic interactions with newer antipsychotics occur at the metabolic level and usually involve changes in the activity of the major drug-metabolizing enzymes involved in their biotransformation, i.e. the cytochrome P450 (CYP) monooxygenases and/or uridine diphosphate-glucuronosyltransferases (UGT). Clozapine is metabolized primarily by CYP1A2, with additional contribution by other CYP isoforms. Risperidone is metabolized primarily by CYP2D6 and, to a lesser extent, CYP3A4. Olanzapine undergoes both direct conjugation and CYP1A2-mediated oxidation. Quetiapine is metabolized by CYP3A4, while sertindole and aripiprazole are metabolized by CYP2D6 and CYP3A4. Ziprasidone pathways include aldehyde oxidase-mediated reduction and CYP3A4-mediated oxidation. Amisulpride is primarily excreted in the urine and undergoes relatively little metabolism. While novel antipsychotics are unlikely to interfere with the elimination of other drugs, co-administration of inhibitors or inducers of the major enzymes responsible for their metabolism may modify their plasma concentrations, leading to potentially significant effects. Most documented metabolic interactions involve antidepressant and anti-epileptic drugs. Of a particular clinical significance is the interaction between fluvoxamine, a potent CYP1A2 inhibitor, and clozapine. Differences in the interaction potential among the novel antipsychotics currently available may be predicted based on their metabolic pathways. The clinical relevance of these interactions should be interpreted in relation to the relative width of their therapeutic index. Avoidance of unnecessary polypharmacy, knowledge of the interaction profiles of individual agents, and careful individualization of dosage based on close evaluation of clinical response and, possibly, plasma drug concentrations are essential to prevent and minimize potentially adverse drug interactions in patients receiving newer antipsychotics.

Bifeprunox: a novel antipsychotic agent with partial agonist properties at dopamine D2 and serotonin 5-HT1A receptors

Most second-generation, atypical, dopamine (DA) D2/5-HT2 blocking antipsychotics still induce extrapyramidal side effects (EPS) in higher doses. Weight gain and metabolic disturbances are also a problem, and negative and cognitive symptoms have not been sufficiently addressed. The current brain DA mesolimbic hyperactive/mesocortical hypoactive hypothesis of schizophrenia suggests that DA D2/5-HT1A receptor partial agonist properties may be more efficacious with less side effects. DA D2 receptor partial agonists may stabilize a hyperactive/hypoactive DA condition. Additional 5-HT1A stimulation may enhance therapeutic efficacy and also improve EPS liability profile. In clinical trials in schizophrenic patients, the novel DA D2/5-HT1A partial agonist bifeprunox indeed demonstrates therapeutic efficacy, a safe EPS profile and appears beneficial regarding weight gain, prolactin, blood lipid and glucose levels and cardiac rhythm. The data on bifeprunox are promising and suggest that combined DA D2/5-HT1A partial agonism may well be important properties for future-generation antipsychotics.

The drug-induced helplessness test: an animal assay for assessing behavioral despair in response to neuroleptic treatment

RATIONALE

Neuroleptic dysphoria encompasses a range of unpleasant subjective responses and, as a result, is difficult to study in preclinical animal models.

OBJECTIVE

Based on the learned helplessness model of depression, increases in escape failures (EFs) in the drug-induced helplessness test (DH) are proposed to reflect drug-induced depressive-like state, a contributing factor to neuroleptic dysphoria in humans.

MATERIALS AND METHODS

Effects of the typical antipsychotic haloperidol and the atypical antipsychotics risperidone, olanzapine, aripiprazole, quetiapine, and clozapine were investigated in the DH test. We further characterized this test by examining compounds affecting motor function, cognition, anxiety, and those with antidepressant activity.

RESULTS

The antipsychotics haloperidol, risperidone, aripiprazole, and olanzapine, all increased EFs, while quetiapine had no effect, and clozapine reduced EFs. Amphetamine, diazepam, and ciproxifan, had no effect on EFs. Scopolamine significantly reduced EFs and MK-801 showed a trend toward reducing EFs at doses not significantly sti mulating locomotor activity. Subchronic, but not acute, imipramine and subchronic fluoxetine significantly reduced EFs at doses significantly suppressing locomotor activity. Dissociation appears to exist between performance in the DH test and compound effects on catalepsy or locomotor activity.

CONCLUSIONS

After discussing potential alternative interpretations of the drug-induced changes of EFs, we propose the DH test as a useful test for assessing a drug-induced, depressive-like state that may contribute to neuroleptic dysphoria.

Pharmacokinetic Variability of Aripiprazole and the Active Metabolite Dehydroaripiprazole in Psychiatric Patients

Aripiprazole is a new atypical antipsychotic drug with a partial agonist activity at dopamine 2 and serotonin 1A receptors. The metabolism of aripiprazole involves both cytochrome P450 2D6 (CYP2D6) and CYP3A4. This study investigated the pharmacokinetic variability of aripiprazole and the active metabolite dehydroaripiprazole on the basis of 155 drug monitoring samples from psychiatric patients treated with therapeutic doses of aripiprazole (10-30 mg/day). Serum concentrations of drug and metabolite were determined by liquid chromatographic and tandem mass spectrometric detection. Pharmacokinetic variability was expressed as the range in concentration/dose (C/D) ratios, and the effect of sex and occasionally coprescribed CYP2D6 or CYP3A4 inhibitors/inducers was studied. In addition, the dose-concentration relationship and combined interquartile range of concentrations obtained at low dose (10-15 mg/day) and high dose (20-30 mg/day) were described. Individual C/D ratios ranged 37-fold for aripiprazole, 78-fold for dehydroaripiprazole, and 27-fold for the active sum of aripiprazole + dehydroaripiprazole. Median C/D ratios in male and female patients differed by less than 15%, and none of the differences were significant (P > 0.14). Cases of concurrent CYP3A4 inducers/inhibitors were not found, but three patients were coprescribed the potent CYP2D6 inhibitors paroxetine or fluoxetine. No consistent difference in C/D ratio was observed in these three patients compared with the rest of the patients. There was a proportional dose-concentration relationship in the population, and the combined interquartile ranges were 230 to 960 nmol/L for aripiprazole and 330 to 1210 nmol/L for aripiprazole + dehydroaripiprazole. In conclusion, pharmacokinetic variability of aripiprazole is extensive in psychiatric patients but apparently not dependent on dose or sex. The variability of the pharmacologic active sum of aripiprazole + dehydroaripiprazole is 25% to 30% less than aripiprazole, suggesting that variability of aripiprazole is partly determined by metabolism to dehydroaripiprazole.

A review of aripiprazole in the treatment of patients with schizophrenia or bipolar I disorder

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.

Efficacy with high-dose aripiprazole after olanzapine-related metabolic disturbances

OBJECTIVE

To report a case in which a patient tolerated and responded to high-dose aripiprazole and lost weight after having been on olanzapine for several years; a secondary objective is to discuss the use of aripiprazole dosages at higher than those recommended in the product's labeling.

CASE SUMMARY

A 57-year-old man with a 30 year history of schizophrenia had been taking olanzapine for 4 years, with the dosage titrated to 20 mg/day, to control the psychosis. After he had gained significant weight with olanzapine (the highest was 102.7 kg), his treatment was switched to aripiprazole. The patient required a high dose of aripiprazole (60 mg/day) to achieve full control of the psychiatric symptoms, and during aripiprazole therapy, he lost the weight he had gained while on olanzapine, weighing 85.9 kg within 7 months after the therapy switch.

DISCUSSION

Dosages of atypical antipsychotics higher than those recommended by the Food and Drug Administration are often used in clinical practice for refractory patients, despite the lack of evidence. The literature available on this subject is limited to small, double-blind trials; open-label trials; and case reports. Although certain patients may benefit from higher doses of atypical antipsychotics, the lack of evidence limits their use.

CONCLUSIONS

High-dose aripiprazole (60 mg/day) was well tolerated and controlled this patient's symptoms effectively. In addition, he lost weight that was gained while being treated with olanzapine. High-dose aripiprazole may be beneficial and safe in refractory patients; however, large, double-blind, randomized clinical trials are needed.

Assays for enhanced activity of low efficacy partial agonists at the D(2) dopamine receptor

BACKGROUND AND PURPOSE

Low efficacy partial agonists at the D2 dopamine receptor may be useful for treating schizophrenia. In this report we describe a method for assessing the efficacy of these compounds based on stimulation of [35S]GTPgammaS binding.

EXPERIMENTAL APPROACH

Agonist efficacy was assessed from [(35)S]GTPgammaS binding to membranes of CHO cells expressing D2 dopamine receptors in buffers with and without Na+. Effects of Na+ on receptor/G protein coupling were assessed using agonist/[3H]spiperone competition binding assays.

KEY RESULTS

When [35S]GTPgammaS binding assays were performed in buffers containing Na+, some agonists (aripiprazole, AJ-76, UH-232) exhibited very low efficacy whereas other agonists exhibited measurable efficacy. When Na+ was substituted by N-methyl D-glucamine, the efficacy of all agonists increased (relative to that of dopamine) but particularly for aripiprazole, aplindore, AJ-76, (-)-3-PPP and UH-232. In ligand binding assays, substitution of Na+ by N-methyl D-glucamine increased receptor/G protein coupling for some agonists -. aplindore, dopamine and (-)-3-PPP - but for aripiprazole, AJ-76 and UH-232 there was little effect on receptor/G protein coupling.

CONCLUSIONS AND IMPLICATIONS

Substitution of Na+ by NMDG increases sensitivity in [(35)S]GTPgammaS binding assays so that very low efficacy agonists were detected clearly. For some agonists the effect seems to be mediated via enhanced receptor/G protein coupling whereas for others the effect is mediated at another point in the G protein activation cycle. AJ-76, aripiprazole and UH-232 seem particularly sensitive to this change in assay conditions. This work provides a new method to discover these very low efficacy agonists.

Dose-dependent rapid-onset akathisia with aripiprazole in patients with schizoaffective disorder

A series of cases are reported in which patients on aripiprazole have developed akathisia, although the literature states that the rate is negligible.

Epidemiology of tardive dyskinesia: Is risk declining with modern antipsychotics?

Second-generation antipsychotic drugs (APDs), including aripiprazole, clozapine, olanzapine, risperidone, quetiapine, and ziprasidone dominate outpatient and inpatient clinical practice, having largely displaced the older neuroleptics. Modern APDs have relatively low risk for acute extrapyramidal syndromes characteristic of older neuroleptics, particularly acute dystonia and Parkinsonism, with variable risks of akathisia and the rare neuroleptic malignant syndrome. Anticipated reduction in risk of tardive dyskinesia (TD) is less well documented. Nearly 50 years after initial reports on TD, it is appropriate to reexamine the epidemiology of this potentially severe late adverse effect of long-term APD treatment in light of current research and practice. We compared recent estimates of incidence and prevalence of TD identified with some modern APDs to the epidemiology of TD in the earlier neuroleptic era. Such comparisons are confounded by complex modern APD regimens, uncommon exposure limited to a single modern APD, effects of previous exposure to typical neuroleptics, and neurological assessments that are rarely prospective or systematic. Available evidence suggests that the risk of TD may be declining, but longitudinal studies of patients never treated with traditional neuroleptics and exposed to only a single modern APD are required to quantify TD risks with specific drugs. Long-term use of APDs should continue to be based on research-supported indications, with regular specific examination for emerging TD.

Antipsychotikainduzierte QT-Verlängerung

Prolongation of myocardial repolarisation, i.e. lengthening of the QT interval on surface electrocardiogram, has been recognised as a side effect of many drugs, including antipsychotics. In predisposed individuals, abnormal excessive QT prolongation and severe ventricular arrhythmias (the ventricular tachycardia type 'torsade de pointes', or TdP) may occur. In almost all cases, additional factors are present that increase the propensity of patients to develop TdP, such as serum hypokalemia, the combination of drugs prolonging repolarisation, overdosing, intoxication, and factors interfering with drug metabolism and excretion. Serum hypokalemia and/or bradycardia may induce TdP alone, in the absence of drugs prolonging the QT interval. Experimental studies demonstrate that prolongation of myocardial repolarisation is a class effect of neuroleptics. Clinically, the extent to which individual drugs prolong the QT interval varies. Among the antipsychotics, thioridazine has the greatest propensity to induce abnormal QT prolongations and TdP. Case reports of TdP with other antipsychotics have been published. Physicians prescribing physicians these drugs must be aware that they can induce proarrhythmia in individual cases. They should also be aware of the circumstances which are necessary for abnormal QT prolongation and TdP to develop. Patients should be monitored with regard to these risk factors before and during drug treatment.

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

Ziprasidone (Geodon, Zeldox) is an atypical antipsychotic agent with a unique neurotransmitter receptor-binding profile. The oral formulation is indicated for the treatment of adult patients with schizophrenia and the intramuscular formulation for the control of acute agitation in these patients. In adult patients with schizophrenia or schizoaffective disorder, oral ziprasidone was effective at a dosage of 40-80 mg twice daily in patients experiencing a phase of acute illness, and at a dosage of 20-80 mg twice daily in those with chronic schizophrenia or schizoaffective disorder, including those who were symptomatically stable. Ziprasidone offers the advantage over most other atypical antipsychotic agents of being available in a fast-acting intramuscular formulation for control of acute agitation, thus providing clinicians with the option to safely and effectively transition to longer-term treatment with the oral formulation. Although careful consideration should be given to the propensity for ziprasidone to cause corrected QT (QTc) interval prolongation, albeit at a relatively low incidence, the drug generally has a favourable tolerability profile of low extrapyramidal syndrome (EPS) liability, neutral bodyweight gain, and potentially low propensity for metabolic complications. Thus, ziprasidone is an effective option for the management of patients with schizophrenia or schizoaffective disorder, with the intramuscular formulation providing a useful option for the treatment of acute agitation in these patients.

Intrinsic efficacy of antipsychotics at human D2, D3, and D4 dopamine receptors: identification of the clozapine metabolite N-desmethylclozapine as a D2/D3 partial agonist

Drugs that antagonize D2-like receptors are effective antipsychotics, but the debilitating movement disorder side effects associated with these drugs cannot be dissociated from dopamine receptor blockade. The "atypical" antipsychotics have a lower propensity to cause extrapyramidal symptoms (EPS), but the molecular basis for this is not fully understood nor is the impact of inverse agonism upon their clinical properties. Using a cell-based functional assay, we demonstrate that overexpression of Galphao induces constitutive activity in the human D2-like receptors (D2, D3, and D4). A large collection of typical and atypical antipsychotics was profiled for activity at these receptors. Virtually all were D2 and D3 inverse agonists, whereas none was D4 inverse agonist, although many were potent D4 antagonists. The inverse agonist activity of haloperidol at D2 and D3 receptors could be reversed by mesoridazine demonstrating that there were significant differences in the degrees of inverse agonism among the compounds tested. Aripiprazole and the principle active metabolite of clozapine NDMC [8-chloro-11-(1-piperazinyl)-5H-dibenzo [b,e] [1,4] diazepine] were identified as partial agonists at D2 and D3 receptors, although clozapine itself was an inverse agonist at these receptors. NDMC-induced functional responses could be reversed by clozapine. It is proposed that the low incidence of EPS associated with clozapine and aripiprazole used may be due, in part, to these partial agonist properties of NDMC and aripiprazole and that bypassing clozapine blockade through direct administration of NDMC to patients may provide superior antipsychotic efficacy.

Clinical trial design in schizophrenia: implications for clinical decisions

PURPOSE OF REVIEW

Results from clinical trials do not necessarily provide information for decisions in clinical practice. This review aims to present strengths and limitations of different methodological types of clinical trials and to offer an overview of how knowledge from clinical trails can be distilled for clinical practice. Selected key questions in the treatment of schizophrenia are presented, with a focus on the possibilities and restrictions of translating trial results into real-world practice.

RECENT FINDINGS

Randomized controlled trials are the gold standard for proving efficacy of a diagnostic or therapeutic procedure. They have a high degree of internal validity and a clear-cut message when conducted to good-quality standards but suffer from a lack of generalizability (external validity). Effectiveness studies evaluate effects of treatments under conditions approximating usual care. They may include patient-centred outcomes or health economic evaluations. According to the type of trial, specific problems arise in the interpretation of results. Typical examples are given for the treatment of acute exacerbations of schizophrenia, for relapse prevention and for the treatment of cognitive impairment.

SUMMARY

Clinical decisions have to be made upon the best knowledge. Therefore, well conducted studies addressing all major issues from all relevant perspectives are needed. The assessment of a treatment regimen for clinical utility requires both efficacy and effectiveness studies. An understanding of the design, analysis and conventions of both study types is essential for the interpretation of results and their translation to the clinical decision-making process.

From clinical research to clinical practice: a 4-year review of ziprasidone

Ziprasidone is a second-generation antipsychotic that received Food and Drug Administration approval in February 2001. It has a unique receptor profile that includes high-affinity antagonist activity at dopamine D2 receptors, inverse agonist activity at serotonin (5-HT)2A receptors, agonist activity at 5-HTlA receptors, and a relatively high affinity for the serotonin and norepinephrine transporters. The 5-HTIA affinity, together with the inhibitory effect on mono-amine reuptake, may underlie the hypothesized beneficial effects on comorbid affective and cognitive abnormalities in schizophrenia and schizoaffective disorder. The short-term efficacy of ziprasidone for core positive symptoms of schizophrenia appears to be comparable to other conventional and atypical antipsychotics. The short-term efficacy of ziprasidone in acute mania has been established based on two 3-week, double-blind, placebo-controlled trials.Open-label treatment for up to 52 weeks confirms the sustained efficacy and safety of ziprasidone in bipolar disorder. Maintenance studies in schizophrenia and schizoaffective disorder indicate that long-term ziprasidone therapy is effective in preventing relapse, while maintaining cognitive and psychosocial benefits. The safety database suggests that the overall cardiovascular and cerebrovascular risk associated with ziprasidone is lower than with other atypicals, with notably lower risk of drug-related increases in weight, glucose, or lipids. The data also suggest a modestly increased risk of QTc prolongation that is not dose related or linked to torsades de pointes. Switching to ziprasidone from other atypicals appears to improve both clinical symptoms and metabolic parameters, though more studies are needed to fully characterize these benefits. This monograph summarizes the efficacy, tolerability, and safety of oral ziprasidone in the treatment of schizophrenia, schizoaffective disorder, and bipolar mania.

Aripiprazole

Aripiprazole is a new chemical entity with a unique pharmacological profile. It has strong affinities for certain dopamine receptors, and intermediate affinity for serotonin, adrenergic and histamine receptors. Partial agonism of the D2 dopamine and 5HT1A serotonin receptors, and antagonism of the 5HT2 serotonin receptor are believed to be the functional basis of its therapeutic efficacy. Its clinical effects are best documented in patients suffering from schizophrenia and bipolar disorder, in which it has been demonstrated to have antipsychotic and antimanic properties superior to placebo in dose ranges of 10-30 mg/day. Two published longer term trials document maintenance of antipsychotic effects and relapse prevention in schizophrenia patients. In general, aripiprazole seems to be a well-tolerated drug, especially with regard to metabolic side effects. The most commonly reported side effects include restlessness/akathisia, somnolence and nausea. These may be dose-dependent and usually occur early on during treatment, with many patients developing tolerance. Aripiprazole is an interesting and important addition to the currently available spectrum of antipsychotic drugs. Further studies in other indications and clinical trials that confirm results from the Phase II and III clinical development programme are eagerly awaited.

High performance liquid chromatographic methods for the determination of aripiprazole with ultraviolet detection in rat plasma and brain: Application to the pharmacokinetic study

High performance liquid chromatographic (HPLC) methods were validated for the determination of aripiprazole (OPC-14597, Abilify) in rat plasma and brain. Separation was by Nova-pak phenyl column; flow rate, 1.0 ml/min; mobile phase, acetonitrile-methanol-20 mM sodium sulfate-acetic acid (27:25:48:1, v/v/v/v); UV detection at 254 nm. Reproducibility in plasma and brain showed excellent precision (within 7.8 and 10.6%) and accuracy (96.0-102.4% and 99.0-108.7%) with calibration curve ranges 10.0-2000 ng/ml and 30.0-6000 ng/g, respectively. Validated HPLC methods were successfully applied to pharmacokinetic study of aripiprazole in rats, demonstrating brain concentrations after oral administration five times higher than plasma concentrations.

Le récepteur dopaminergique D3: nouvelle cible pour un traitement amélioré de la schizophrénie

Schizophrenia is a complex and serious disorder which affects some 0.5-1.0% of the population. The disease generally begins in adolescence. This early onset, together with the progressive and often irreversible nature of schizophrenia, account for its high social cost. Positive symptoms, such as hallucinations, are generally well-controlled by antipsychotics, whereas cognitive and deficit symptoms are poorly-treated. All antipsychotic agents, irrespective of their overall receptor-binding profiles, interact with dopaminergic mechanisms that are known to be perturbed in schizophrenic patients. Dopamine exerts its actions via five classes of receptor, offering a broad palette of targets for the conception of novel antipsychotic agents. The present article focuses on the relevance of dopamine D3 receptors to the aetiology and treatment of schizophrenia. Experimental studies suggest that, as compared to other drugs, antipsychotic agents which preferentially block D3 receptors may possess therapeutic advantages, notably in the control of cognitive symptoms. The first clinical studies for the evaluation of this hypothesis have recently got underway.

Aripiprazole, a novel antipsychotic agent: Dopamine D2 receptor partial agonist

It is obvious that DA is an important neurotransmitter in vivo. It is involved in a variety of physiological processes such as mental processes, motor function and hormone regulation. In this context, it is quite understandable that a DA D2 receptor antagonist that inhibits the DA D2 receptor regardless of the state of activity of dopaminergic neurotransmission and inhibit the physiological function of DA can have a variety of adverse effects. In contrast to DA D2 antagonists, aripiprazole acts as an antagonist at the DA D2 receptor in the state of excessive dopaminergic neurotransmission, while it acts as an agonist at the DA D2 receptor in the state of low dopaminergic neurotransmission, and thus attempts to bring the state of dopaminergic neurotransmission to normal. This activity of aripiprazole to regulate dopaminergic neurotransmission is physiologically reasonable, and can be regarded as a stabilizing effect, for which aripiprazole is called a dopamine system stabilizer.

Genetics and Epigenetics in Major Psychiatric Disorders

No specific gene has been identified for any major psychiatric disorder, including schizophrenia, in spite of strong evidence supporting a genetic basis for these complex and devastating disorders. There are several likely reasons for this failure, ranging from poor study design with low statistical power to genetic mechanisms such as polygenic inheritance, epigenetic interactions, and pleiotropy. Most study designs currently in use are inadequate to uncover these mechanisms. However, to date, genetic studies have provided some valuable insight into the causes and potential therapies for psychiatric disorders. There is a growing body of evidence suggesting that the understanding of the genetic etiology of psychiatric illnesses, including schizophrenia, will be more successful with integrative approaches considering both genetic and epigenetic factors. For example, several genes including those encoding dopamine receptors (DRD2, DRD3, and DRD4), serotonin receptor 2A (HTR2A) and catechol-O-methyltransferase (COMT) have been implicated in the etiology of schizophrenia and related disorders through meta-analyses and large, multicenter studies. There is also growing evidence for the role of DRD1, NMDA receptor genes (GRIN1, GRIN2A, GRIN2B), brain-derived neurotrophic factor (BDNF), and dopamine transporter (SLC6A3) in both schizophrenia and bipolar disorder. Recent studies have indicated that epigenetic modification of reelin (RELN), BDNF, and the DRD2 promoters confer susceptibility to clinical psychiatric conditions. Pharmacologic therapy of psychiatric disorders will likely be more effective once the molecular pathogenesis is known. For example, the hypoactive alleles of DRD2 and the hyperactive alleles of COMT, which degrade the dopamine in the synaptic cleft, are associated with schizophrenia. It is likely that insufficient dopaminergic transmission in the frontal lobe plays a role in the development of negative symptoms associated with this disorder. Antipsychotic therapies with a partial dopamine D2 receptor agonist effect may be a plausible alternative to current therapies, and would be effective in symptom reduction in psychotic individuals. It is also possible that therapies employing dopamine D1/D2 receptor agonists or COMT inhibitors will be beneficial for patients with negative symptoms in schizophrenia and bipolar disorder. The complex etiology of schizophrenia, and other psychiatric disorders, warrants the consideration of both genetic and epigenetic systems and the careful design of experiments to illumine the genetic mechanisms conferring liability for these disorders and the benefit of existing and new therapies.