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

Childhood disintegrative disorder

We are presenting a case of a 10-year-old female child who presented with normal development till 5 years of age followed by deterioration in previously acquired language and social skills with stereotypic hand movements suggestive of childhood disintegrative disorder. This case is reported as this condition is very rare.

Prolactin concentrations during aripiprazole treatment in relation to sex, plasma drugs concentrations and genetic polymorphisms of dopamine D2 receptor and cytochrome P450 2D6 in Japanese patients with schizophrenia

AIMS

The authors investigated the correlation between prolactin concentrations during aripiprazole treatment and various factors, including age, sex, plasma concentrations of aripiprazole and its active metabolite, dehydroaripiprazole, and genetic polymorphisms of dopamine D2 receptor (DRD2) and cytochrome P450(CYP)2D6.

METHODS

The subjects were 70 inpatients with schizophrenia (36 men and 34 women), receiving fixed doses of aripiprazole (24 mg in 45 cases and 12 mg in 25 cases) for periods of between 2 and 30 weeks. Prolactin concentrations were measured by chemiluminescence immunoassay. Plasma concentrations of aripiprazole and dehydroaripiprazole were measured using liquid chromatography with mass spectrometric detection. The genotypes of Taq1A, -141C Ins/Del DRD2 and CYP2D6 were detected by polymerase chain reaction methods.

RESULTS

Prolactin concentrations were significantly higher in women than in men (8.9 ± 7.5 vs 3.4 ± 3.0 ng/mL, P < 0.001). No correlations were found between prolactin concentrations and plasma concentrations of aripiprazole, dehydroaripiprazole or the sum of the two compounds. Prolactin concentrations were not affected by any polymorphism.

CONCLUSION

The present study suggests that only sex plays a significant role in prolactin concentrations during aripiprazole treatment.

The increasing frequency of mania and bipolar disorder: causes and potential negative impacts

The frequency of mania has not changed during the last century even with the development of new diagnostic criteria sets. More specifically, from the mid-1970s to 2000, the rate of mania (variably labeled major affective disorder-bipolar disorder and bipolar I disorder) was consistently identified in US and international studies as ranging from 0.4% to 1.6%. By the late 1990s to the 2000s, the prevalence reported by some researchers for bipolar disorders (I and II and others) was in the 5% to 7% and higher ranges. The purpose of this paper was to review explanations for this change and the potentially negative impacts on the field.

Atypical antipsychotics: trends in analysis and sample preparation of various biological samples

Atypical antipsychotics are increasingly popular and increasingly prescribed. In some countries, they can even be obtained over-the-counter, without a prescription, making their abuse quite easy. Although atypical antipsychotics are thought to be safer than typical antipsychotics, they still have severe side effects. Intoxications are not rare and some of them have a fatal outcome. Drug interactions involving atypical antipsychotics complicate patient management in clinical settings and the determination of the cause of death in fatalities. In view of the above, analytical strategies that can efficiently isolate atypical antipsychotics from a variety of biological samples and quantify them accurately, sensitively and reliably, are of utmost importance both for the clinical, as well as for the forensic toxicologist. In this review, we will present and discuss novel analytical strategies that have been developed from 2004 to the present day for the determination of atypical antipsychotics in various biological samples.

Aripiprazole: a review of its use in the management of mania in adults with bipolar I disorder

Aripiprazole (Abilify®) is an atypical antipsychotic indicated for the treatment of mania associated with bipolar I disorder. It is unique in its class, as it is a partial agonist of dopamine D(2) and D(3), and serotonin 5-HT(1A) receptors and a modest antagonist of 5-HT(2A) receptors. This article reviews the pharmacological properties, clinical efficacy and tolerability of oral aripiprazole in the management of mania associated with bipolar I disorder in adults. In well designed clinical trials in patients with recent manic or mixed episodes associated with bipolar I disorder, oral aripiprazole monotherapy or adjunctive therapy to lithium or valproate improved symptoms of mania following short-term (≤12 weeks) or maintenance (≤100 weeks) treatment. In addition, maintenance treatment with aripiprazole (as monotherapy or adjunctive therapy) prevented the recurrence of any mood episodes or manic episodes (but not depressive episodes) in patients who had previously been stabilized and maintained on aripiprazole. Aripiprazole was generally well tolerated in these studies and was associated with a low risk of prolactin elevation, corrected QT interval prolongation and metabolic disturbances. Extrapyramidal symptoms occurred in up to 28% of aripiprazole recipients, but after longer-term treatment (≤100 weeks), symptom severity did not differ significantly from that in placebo recipients. Aripiprazole treatment generally did not increase bodyweight to a clinically relevant extent; however, more patients receiving aripiprazole monotherapy than placebo had clinically significant bodyweight gain during 100 weeks' treatment. Additionally, in a comparative trial, aripiprazole monotherapy was at least as effective as haloperidol monotherapy in terms of improving symptoms of mania, but had the advantage of a lower incidence of some adverse events, such as extrapyramidal symptom-related adverse events. Further trials comparing aripiprazole with other agents, including atypical antipsychotics, would help to definitively position aripiprazole relative to these agents. Current guidelines recommend aripiprazole as a first-line option (as monotherapy or adjunctive therapy) for the short-term treatment of mania associated with bipolar I disorder, and as a first-line (as monotherapy) or second-line (as adjunctive therapy) option for preventing the recurrence of mood episodes during longer-term therapy.

An improved simple LC-MS/MS method for the measurement of serum aripiprazole and its major metabolite

BACKGROUND AND OBJECTIVES

Current liquid chromatographic tandem mass spectrometry (LC-MS/MS) methods to measure serum levels of aripiprazole (Ar) and dehydroaripiprazole (DHAr) are sensitive, but difficult to use in a hospital context. We aimed to develop a rapid LC-MS/MS method allowing reliable level measurement in the presence of co-administered drugs, withdrawing samples from 22 patients with acute agitation receiving 9.75 mg aripiprazole IM injection.

METHOD

We developed a sensitive and selective HPLC-MS/MS method to measure serum Ar and DHAr levels in a hospital laboratory, requiring minimal sample preparation and inferior sample volume compared to previous LC-MS/MS methods. Analytes were separated on a reversed-phase HPLC (run-time, 10 min). A triple quadrupole tandem mass spectrometer was used for quantitative analysis in positive mode by a multiple reaction monitoring. Samples were drawn 2, 4, 6, and 24h post-injection.

RESULTS

Calibration curves (2-1000 ng/mL for Ar and 3.5-500 ng/mL for DHAr) were linear, with mean correlation coefficient >0.9998. Within- and between-day precision and accuracy were within 10%. Mean recovery was 95.2 ± 4.5% for Ar and 97.6 ± 7.2% for DHAr. Ar and DHAr peaks were not affected by other co-administered psychotropic drugs.

CONCLUSION

Our method measured Ar and DHAr concentrations reliably, simply and rapidly without employing many reagents, as currently existing methods.

Aripiprazole: a review of its use in the management of schizophrenia in adults

Oral aripiprazole (Abilify®) is an atypical antipsychotic agent that is approved worldwide for use in adult patients with schizophrenia. It is a quinolinone derivative that has a unique receptor binding profile as it exhibits both partial agonist activity at dopamine D(2) receptors and serotonin 5-HT(1A) receptors and antagonist activity at 5-HT(2A) receptors. In several well designed, randomized, clinical trials of 4-6 weeks duration, aripiprazole provided symptomatic control for patients with acute, relapsing schizophrenia or schizoaffective disorder. Furthermore, following 26 weeks' treatment, the time to relapse was significantly longer for patients with chronic, stabilized schizophrenia receiving aripiprazole compared with those receiving placebo. Using a variety of efficacy outcomes, aripiprazole showed a mixed response when evaluated against other antipsychotic agents in randomized clinical trials. Longer-term data showed that improvements in remission rates and response rates favoured aripiprazole over haloperidol, although, the time to failure to maintain a response was not significantly different between the treatment arms. On the other hand, improvements in positive and negative symptom scores mostly favoured olanzapine over aripiprazole, although, the time to all-cause treatment discontinuation was not significantly different between the two treatments. Several open-label, switching trials showed that aripiprazole provided continued control of symptoms in patients with schizophrenia or schizoaffective disorder. Using a variety of efficacy outcomes or quality-of-life scores, longer-term treatment generally favoured patients switched to receive aripiprazole compared with standard-of-care oral antipsychotics. Aripiprazole was generally well tolerated in patients with schizophrenia. In particular, its use seems to be associated with a lower incidence of extrapyramidal symptoms than haloperidol and fewer weight-gain issues than olanzapine. Aripiprazole also showed a favourable cardiovascular tolerability profile and its use was associated with a reduced risk of metabolic syndrome than placebo or olanzapine. As a consequence, aripiprazole may provide a more cost-effective treatment option compared with other atypical antipsychotics. In conclusion, oral aripiprazole provides an effective and well tolerated treatment alternative for the acute and long-term management of patients with schizophrenia.

Critical appraisal of lurasidone in the management of schizophrenia

Lurasidone is a new atypical antipsychotic in the benzoisothiazoles class of chemicals. Like most second-generation antipsychotics it is a full antagonist at dopamine D(2) and serotonin 5-HT(2A) receptors, and is a partial agonist at 5-HT(1A) receptors, a property shared by some but not all older agents. It has much greater affinity for 5-HT(7) subtype receptors than other atypical antipsychotics. Pharmacokinetic studies showed that lurasidone is reasonably rapidly absorbed, with bioavailability appearing to be increased by food. Lurasidone undergoes extensive metabolism to a number of metabolites, some of which retain pharmacological activities. Metabolism is mainly by CYP3A4, resulting in steady-state concentrations that vary between individuals and are potentially affected by strong inducers and inhibitors of this enzyme. Short-term clinical trials have demonstrated the efficacy of lurasidone in acute schizophrenia, with doses of 40 and 80 mg/day giving significant improvements from baseline in the PANSS and BPRS scores. The most common adverse events are nausea, vomiting, akathisia, dizziness, and sedation, with minimal increases in the risk of developing metabolic syndrome. Lurasidone did not raise the risk of QTc interval prolongation, although additional studies are required. Long-term trials are also needed to assess the risk of new-onset diabetes. Ongoing trials in patients with bipolar disorder are being completed but, again, efficacy and safety have been investigated only in a few short-term clinical trials.

Serotonergic mechanisms as targets for existing and novel antipsychotics

A variety of serotonin (5-HT) receptors, especially 5-HT(2A), 5-HT(1A), 5-HT(6), 5-HT(7), and 5-HT(2C), have been postulated to contribute to the mechanism of action of atypical antipsychotic drugs (APDs), i.e., APDs which cause fewer extrapyramidal side effects (EPS) at clinically optimal doses, in contrast with typical APDs, which are more likely to cause EPS. This advantage, rarely disputed, has made such drugs the preferred treatment for schizophrenia and other indications for APDs. These 5-HT receptors are still of interest as components of novel multireceptor or stand-alone APDs, and potentially to remediate cognitive deficits in schizophrenia. Almost all currently available atypical APDs are 5-HT(2A) receptor inverse agonists, as well as dopamine (DA) D(2) receptor antagonists or partial agonists. Amisulpride, an exceptional atypical APD, has 5-HT(7) antagonism to complement its DA D(2/3) antagonism. Some atypical APDs are also 5-HT(1A) partial agonists, 5-HT(6), or 5-HT(7) antagonists, or some combination of the above. 5-HT(2C) antagonism has been found to contribute to the metabolic side effects of some atypical APDs, whereas 5-HT(2C) agonists have potential as stand-alone APDs and/or cognitive enhancers. This review will provide an update of current preclinical and clinical evidence for the role of these five 5-HT receptors in the actions of current APDs and for the development of novel psychotropic drugs.

Aripiprazole induced transient myopia: a case report and review of literature

Aripiprazole is a drug belonging to the group of atypical antipsychotics. Ocular side effects of aripiprazole are rare. We report a case of transient myopia in a 33-year-old male who was being treated for schizophrenia with oral quetiapine and was recently supplemented with aripiprazole. One month after the addition of aripiprazole the patient reported sudden onset painless blurring of vision in both eyes. He was found to have myopia of-3.0 diopters in both eyes; his corrected visual acuity being 20/20. He was advised to discontinue aripiprazole. Ten days later on examination, the patient had an uncorrected visual acuity of 20/20 in both eyes. The stoppage of symptoms on stopping the drug indicates a strong correlation between the drug and the adverse effect. Ophthalmologists and psychiatrists must be aware of this reversible adverse drug reaction, so it may be treated promptly.

[Aripiprazole use in children and adolescent psychiatric patients]

Aripiprazole inaugurates a new generation of antipsychotics called dopamine-serotonin system stabilizers. Its mechanism of action is different as aripiprazole is a partial dopamine D(2) and serotonin 5-HT(1A) receptor agonist and 5-HT(2A) receptor antagonist. Therefore, aripiprazole is thought to have an antagonistic action in the mesolimbic pathway but an agonistic action in the mesocortical pathway, tending to normalize the dopaminergic transmission regardless of the type of imbalance. Clinical trials involving children and adolescents have demonstrated the efficacy of aripiprazole in bipolar disorders, schizophrenia, mood disorders associated with pervasive developmental disorders, in tics and Tourette's. The most frequent side effects are extrapyramidal symptoms and sleepiness and are dose-dependent. Nevertheless, contrary to other second-generation antipsychotics available in France, it induces little weight gain, does not modify lipid and glucidic profiles, does not increase prolactin levels, or induce QTc lengthening. The main advantage of aripiprazole is its good safety profile, with different toxicity targets to other second-generation antipsychotics available in France. Aripiprazole appears to be an alternative for children and adolescents who are vulnerable to these side effects and are having trouble coping with them.

Aripiprazole: in the treatment of irritability associated with autistic disorder in pediatric patients

Aripiprazole is an atypical antipsychotic approved for the treatment of irritability associated with autistic disorder in pediatric patients aged 6-17 years. In two, randomized, double-blind, placebo-controlled studies in pediatric patients aged 6-17 years with irritability associated with autistic disorder, 8 weeks of treatment with aripiprazole 2-15 mg/day, compared with placebo, resulted in significant improvements in the Aberrant Behavior Checklist Irritability subscale score at endpoint (primary endpoint), and the mean Clinical Global Impression-Improvement score. Aripiprazole was generally well tolerated in this patient population in the two 8-week studies and a 52-week study, with most adverse events being mild to moderate in severity. Aripiprazole was associated with weight gain in both the short- and long-term studies; data from the long-term study indicated that the increase in bodyweight reached a plateau at 3-6 months.

Aripiprazole augmentation in the treatment of military-related PTSD with major depression: a retrospective chart review

BACKGROUND

In this chart review, we attempted to evaluate the benefits of adding aripiprazole in veterans with military-related PTSD and comorbid depression, who had been minimally or partially responsive to their existing medications.

METHODS

A retrospective chart review of patients who received an open-label, flexible-dose, 12- week course of adjunctive aripiprazole was conducted in 27 military veterans meeting DSM-IV criteria for PTSD and comorbid major depression. Concomitant psychiatric medications continued unchanged, except for other antipsychotics which were discontinued prior to initiating aripiprazole. The primary outcome variable was a change from baseline in the PTSD checklist-military version (PCL-M) and the Beck Depression Inventory (BDI-II).

RESULTS

PTSD severity (Total PCL scores) decreased from 56.11 at baseline to 46.85 at 12-weeks (p < 0.0001 from Wilcoxon signed rank test) and the depression severity decreased from 30.44 at baseline to 20.67 at 12-weeks (p < 0.0001 from Wilcoxon signed rank test). Thirty seven percent (10/27) were considered responders, as defined by a decrease in total PCL scores of at least 20 percent and 19% (5/27) were considered as responders as defined by a decrease in total BDI score of at least 50%.

CONCLUSIONS

The addition of aripiprazole contributed to a reduction in both PTSD and depression symptomatology in a population that has traditionally demonstrated poor pharmacological response. Further investigations, including double-blind, placebo-controlled studies, are essential to confirm and further demonstrate the benefit of aripiprazole augmentation in the treatment of military related PTSD.

Tardive dyskinesia: treatment with aripiprazole

Tardive dyskinesia is characterized by choreiform movements, or rhythmic abnormal involuntary movements of the face, mouth, tongue, trunk, and limbs. It is frequently associated with the use of neuroleptic medications. The choreiform movements are irreversible in some patients, even after the drug is withdrawn. Although no reliable treatment for tardive dyskinesia exists, atypical antipsychotics are associated with a significantly lower incidence of tardive dyskinesia than typical antipsychotics. Moreover, recent reports suggest that atypical antipsychotics may have a beneficial effect on tardive dyskinesia remission. Until recently, evidence for the effectiveness of aripiprazole on tardive dyskinesia has been mixed. Aripiprazole has a unique mechanism of action and has various effects in tardive dyskinesia. The drug acts as a partial D₂ receptor agonist that can stabilize D₂ up-regulation, and as a partial 5-HT_1A receptor agonist and a 5-HT_2A receptor antagonist, and can increase the release of dopamine in the striatum.

Antipsychotics prescribing patterns of patients with schizophrenia admitted to korean general hospital psychiatric unit: 2001 to 2008

Objective

Although the standard of treatment for schizophrenia is antipsychotic monotherapy, overall psychotropic polypharmacy including antipsychotic polypharmacy is increasingly practiced by clinicians. However, there are very few studies that assess the prescription patterns of psychotropic drugs for patients with schizophrenia in Korea. The objective of this study is to describe changes in prescription patterns with respect to antipsychotic polypharmacy and overall psychotropic polypharmacy.

Methods

In this retrospective study, we reviewed all psychotropic drugs prescribed at the time of discharge for patients diagnosed as having schizophrenia (DSM-IV criteria) who entered a psychiatric unit of a Korean general hospital from 2001 to 2008. These included a total of 467 patients.

Results

Of the 467 patients in this study, 205 (43.9%) were discharged with antipsychotic monotherapy and the rest, 262 (56.1%), were discharged with a polypharmacy regimen. A total of 9% of the studied patients received more than two antipsychotic drugs. The most frequent combination of antipsychotics was clozapine and aripiprazole, followed by clozapine and amisulpride, and risperidone and olanzapine. The ratio of patients discharged with a polypharmacy regimen including antipsychotic polypharmacy increased from 2001 to 2008. In relation to the mean dose of all antipsychotic drugs at the time of discharge, mean length of hospital stay and mean initial global assessment of functioning scores on admission statistically significant differences were not detected between both monotherapy and polypharmacy groups.

Conclusion

The main finding of this study is that polypharmacy with antipsychotics and other psychotropic medicines increased in our psychiatric unit from 2001 to 2008. The rates of antipsychotic polypharmacy in our study were less than those described in our literature review.

Pharmacokinetics and metabolism update for some recent antipsychotics

INTRODUCTION

The search for drugs that reduce psychotic symptoms, with minimal adverse effects, has led to the development of new agents that act somewhat differently from their older antipsychotic counterparts. These agents, which include aripiprazole, lurasidone and perospirone, act by targeting both D₂ and 5-HT(1A) receptors, in addition to other characteristic receptors.

AREAS COVERED

This article covers the pharmacokinetics and metabolism of aripiprazole, perospirone, lurasidone and cariprazine. The review also describes the effects of physiological and pathological variables on these drugs as well as potential drug interactions. The author provides the reader with knowledge of the fundamental pharmacokinetic characteristics and metabolic pathways of these new antipsychotics, emphasizing the clinically important common features and differences compared to other older agents.

EXPERT OPINION

Aripiprazole, perospirone, lurasidone and cariprazine share some of the pharmacokinetic characteristics of older, lipophilic antipsychotics and, like these, each has some distinct pharmacokinetic features that are clinically beneficial and some that are not. We await the results of future practical effectiveness trials of these new antipsychotics and their follow-on derivatives to learn more about their benefit/risk profile compared with established antipsychotics. It is hoped that some of these newer antipsychotics will not only increase the range of pharmacotherapeutic options, but decisively improve the expectations of psychotherapy for schizophrenia.

The effect of coadministration of duloxetine on steady-state serum concentration of risperidone and aripiprazole: a study based on therapeutic drug monitoring data

Previous studies have categorized duloxetine as a moderate inhibitor of CYP2D6. The aim of the present study was to investigate the potential interactions between duloxetine and the two CYP2D6 substrates risperidone and aripiprazole in psychiatric patients. Serum concentration data from patients treated with risperidone (n = 8) or aripiprazole (n = 7) in combination with duloxetine were retrieved from therapeutic drug monitoring files at the Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway. The degree of interaction was assessed by comparing the data with a control group of CYP2D6-genotyped patients (homozygous "extensive metabolizers") using oral risperidone or aripiprazole without duloxetine. Coadministration of duloxetine did not significantly increase the concentration of the parent drug or the parent drug/metabolite ratio of either risperidone or aripiprazole. The present study therefore indicates that duloxetine may safely be used concomitantly with risperidone or aripiprazole.

Aripiprazole as adjunctive therapy for patients with major depressive disorder: overview and implications of clinical trial data

Aripiprazole was initially approved to treat schizophrenia and later approved for bipolar mania, as a monotherapy and an adjunctive therapy (manic or mixed episodes), and for irritability associated with autism. Aripiprazole is a partial agonist at dopamine D(2) and D(3) and serotonin 5-HT(1A) receptors, and is an antagonist at 5-HT(2A) receptors. This profile, and convincing preliminary data from small-scale studies, provided the rationale for the large-scale exploration of aripiprazole for unipolar depression. Recently, three 6-week, large-scale, randomized, double-blind, placebo-controlled clinical trials demonstrated clinically meaningful efficacy for aripiprazole as an adjunctive therapy to antidepressants for treating major depressive disorder (MDD). In November 2007, aripiprazole was approved by the US FDA as an adjunctive therapy to antidepressants for treating MDD, with support from two of the above-mentioned trials. In the trials, aripiprazole was demonstrated to be safe and well tolerated, and showed a minimal trend for weight gain over the course of a 6-week treatment. The incidence of akathisia was higher than that reported in studies of patients with schizophrenia; however, most cases were mild to moderate and infrequently lead to discontinuation (5/1090 from all three trials). This comprehensive review provides an overview of the data from all three 6-week studies (including a pooled analysis) and from an unpublished 52-week, open-label extension study, to inform physicians and facilitate reasonable treatment decisions. In addition, specific issues associated with the use of aripiprazole as an adjunctive therapy in patients with MDD, including possible early treatment effect, appropriate timing of therapy initiation, appropriate dosing and duration of treatment, possible differential effect on depressive subgroups and long-term tolerability, are also discussed.

Pharmacologically active metabolites of currently marketed drugs: potential resources for new drug discovery and development

Biotransformation is the major clearance mechanism of therapeutic agents from the body. Biotransformation is known not only to facilitate the elimination of drugs by changing the molecular structure to more hydrophilic, but also lead to pharmacological inactivation of therapeutic compounds. However, in some cases, the biotransformation of drugs can lead to the generation of pharmacologically active metabolites, responsible for the pharmacological actions. This review provides an update of the kinds of pharmacologically active metabolites and some of their individual pharmacological and pharmacokinetic aspects, and describes their importance as resources for drug discovery and development.

Antipsychotic occupancy of dopamine receptors in schizophrenia

Antipsychotic drugs were introduced in the early 50s on the basis of clinical observations in patients with schizophrenia. Experimental studies later revealed that antagonism at the D(2) dopamine receptor is a common characteristic of all antipsychotic drugs. In the 80s, the advent of brain imaging technologies such as positron emission tomography (PET) allowed for direct noninvasive studies of drug binding in treated patients. The concept receptor occupancy is defined as the fraction (%) of a receptor population that is occupied during treatment with an unlabelled drug. With regard to antipsychotic drugs, the radioligand [(11) C]-raclopride has been the most widely used for binding to the D(2) /D(3) -dopamine receptors. The present review discusses the contribution from molecular imaging to the current understanding of mechanism of action (MoA) of antipsychotic drugs. Consistent initial PET-findings of high D2-receptor occupancy in the striatum of patients responding to different antipsychotic drug treatments provided clinical support for the dopamine hypothesis of antipsychotic drug action. It has subsequently been demonstrated that patients with extrapyramidal syndromes (EPS) have higher occupancy (above 80%) than patients with good response but no EPS (65-80%). The PET-defined interval for optimal antipsychotic drug treatment has been implemented in the evolvement of dose recommendations for classical as well as more recently developed drugs. Another consistent finding is lower D(2) -occupancy during treatment with the prototype atypical antipsychotic clozapine. The MoA of clozapine remains to be fully understood and may include nondopaminergic mechanisms. A general limitation is that currently available PET-radioligands are not selective for any of the five dopamine receptor subtypes. Current attempts at developing such ligands may provide the tools required to refine further the MoA of antipsychotic drugs.

Aripiprazole for late-life schizophrenia

Antipsychotics are frequently used in elderly patients to treat a variety of conditions, including schizophrenia. While extensively studied for their impact in younger populations, there is comparatively limited evidence about the effectiveness of these agents in older patients. Further complicating this situation are the high co-morbidity rates (both psychiatric and medical) in the elderly; age-related changes in pharmacokinetics leading to a heightened proclivity for adverse effects; and the potential for multiple, clinically relevant drug interactions. With this background in mind, we review diagnostic and treatment-related issues specific to elderly patients suffering from schizophrenia and other psychotic conditions, focusing on the potential role of aripiprazole.

Evaluation of akathisia in patients with schizophrenia, schizoaffective disorder, or bipolar I disorder: a post hoc analysis of pooled data from short- and long-term aripiprazole trials

The objective of this article is to assess the clinical characteristics of akathisia in patients with schizophrenia, schizoaffective disorder, or bipolar I disorder receiving aripiprazole, haloperidol, olanzapine, or placebo. We conducted post hoc analyses of pooled safety data from trials in patients with schizophrenia, schizoaffective disorder, and bipolar I disorder. Outcome measures included the incidence of akathisia, time to onset, duration, severity, and discontinuation due to akathisia, concomitant use of benzodiazepines and/or anticholinergics, Barnes Akathisia Rating Scale (BARS) scores, and the correlation between antipsychotic efficacy and akathisia. The results for schizophrenia and schizoaffective disorder were as follows: akathisia in 9% of aripiprazole- and 6% of placebo-treated patients; 12.5% of aripiprazole- versus 24% of haloperidol-treated patients; 11% of aripiprazole- versus 6% of olanzapine-treated patients. Bipolar I disorder: akathisia in 18% of aripiprazole- and 5% of placebo-treated patients. The clinical characteristics of akathisia were similar between each data set, regardless of disease. Akathisia was generally mild-to-moderate in severity. Discontinuation due to akathisia was low in both the schizophrenia trials (aripiprazole 0.3%; placebo 0%; aripiprazole 0.9%; haloperidol 2.3%; aripiprazole 1.2%; olanzapine 0.2%) and the bipolar trials (aripiprazole 2.3%; placebo 0%). Treatment-emergent akathisia was not associated with a poorer clinical response. In conclusion, akathisia with aripiprazole occurred early in treatment, was mild-to-moderate in severity, led to few study discontinuations, and did not compromise therapeutic efficacy.

Effectiveness of switching to aripiprazole from atypical antipsychotics in patients with schizophrenia

OBJECTIVE

To examine changes in cognitive function and clinical features after a switch from atypical antipsychotics to aripiprazole in patients with schizophrenia.

METHOD

Sixty-one patients with schizophrenia treated with atypical antipsychotics participated in this open-label, 26-week study. Antipsychotics were switched to aripiprazole, and neurocognitive functions were measured at 12 and 26 weeks using the computerized battery. The secondary outcome measures were the Positive and Negative Syndrome Scale, the Social and Occupational Functioning Assessment Scale, the Calgary Depression Scale for Schizophrenia, the Subjective Well-being Under Neuroleptics Scale, and the Drug Attitude Inventory (DAI). The safety measures included metabolic parameters, the Simpson-Angus Rating Scale, the Barnes Akathisia Scale, and the Abnormal Involuntary Movement Scale.

RESULTS

Significant improvements in cognitive function were observed in the Verbal Learning Test, the Wisconsin Card Sorting Test, and the Trail Making Test part A after a switch to aripiprazole. Scores on the Positive and Negative Syndrome Scale, the Social and Occupational Functioning Assessment Scale, the DAI, the Simpson-Angus Rating Scale, and the Abnormal Involuntary Movement Scale were significantly improved. The metabolic parameters, including serum cholesterol levels, were also improved. The changes in cognitive measures were not correlated with the changes in positive symptoms or movements scales. The improvement of the scores on the DAI and the delayed recall of the Verbal Learning Test were significantly greater in the patients treated with antipsychotics for less than 1 year than in those treated for more than 1 year, in whom the improvement in metabolic parameters was significantly greater.

CONCLUSIONS

Patients with schizophrenia who switched from their previous antipsychotics to aripiprazole demonstrated improvements in cognitive function, psychotic symptoms, social function, attitude toward medication, and metabolic abnormalities.

The pharmacokinetics of standard antidepressants with aripiprazole as adjunctive therapy: studies in healthy subjects and in patients with major depressive disorder

Possible effects of the atypical antipsychotic aripiprazole on the pharmacokinetics of standard antidepressant therapies (ADTs) were assessed in two open-label, non-randomised studies in healthy subjects (Studies 1 and 2) and two placebo-controlled studies in patients with major depressive disorder (MDD) (Studies 3 and 4). Healthy subjects received venlafaxine 75 mg/day (Study 1; N = 38) or escitalopram 10 mg/ day (Study 2; N = 25) with the addition of aripiprazole 10-20 mg/day (10 mg/day fixed dose in Study 2) for 14 days. Patients with MDD (N = 498; Studies 3 and 4) received escitalopram (10-20 mg/day), fluoxetine (20-40 mg/day), paroxetine controlled-release (37.5-50 mg/day), sertraline (100-150 mg/day) or venlafaxine extended-release (150-225 mg/day) for 8 weeks plus placebo. Incomplete responders were randomised (1:1) to placebo or adjunctive aripiprazole 2-20 mg/day. Blood samples were collected for pharmacokinetic analysis of ADTs. Plasma concentration-time data from Studies 3 and 4 were combined for statistical analysis. In healthy subjects, point estimates [90% CI] for the ratios of geometric means of C( max) (venlafaxine 1.148 [1.083-1.217]; escitalopram 1.04 [0.99-1.09]) and AUC(TAU) (venlafaxine 1.183 [1.130-1.238]; escitalopram 1.07 [1.04-1.11]) indicated no meaningful increase in ADT exposure in the presence of aripiprazole. In patients, point estimates for mean plasma concentration ratios indicated no substantial effect of aripiprazole on any ADT escitalopram 0.970 [0.911-1.033], fluoxetine 1.177 [1.049-1.321], paroxetine 0.730 [0.598-0.892], sertraline 0.958 [0.887-1.035] or venlafaxine 0.966 [0.887-1.051]. Aripiprazole had no meaningful effects on the pharmacokinetics of standard ADTs in either healthy subjects or patients with MDD.

A review of the safety and tolerability of aripiprazole

It seems that the efficacy of aripiprazole for treating schizophrenia is mediated through a combination of partial agonism at dopamine D2 and serotonin 5-HT1A receptors and antagonism at serotonin 5-HT2A receptors. Aripiprazole has also received approval for the treatment of bipolar disorder as adjunctive therapy or monotherapy (manic or mixed episodes) as well as an augmentation therapy of major depressive disorder (MDD) by the US FDA. The overall safety and tolerability of aripiprazole is favorable compared to other atypical antipsychotics across the approved indications. Aripiprazole showed a minimal propensity for clinically significant weight gain and metabolic disruption. However, extrapyramidal side effects, such as akathisia, are reported and may limit its clinical use in some cases, particularly in patients with bipolar disorder and MDD. This review focuses on the tolerability and safety of aripiprazole across a broad spectrum of psychiatric disorders while taking into consideration results from registrational studies as well as findings from studies in the naturalistic setting. In conclusion, whereas the comparative safety and tolerability of aripiprazole has not been systematically evaluated in comparator studies, tolerability and safety issues commonly associated with atypical antipsychotics such as weight gain and metabolic syndrome are less prominent with aripiprazole.

Role of CYP pharmacogenetics and drug-drug interactions in the efficacy and safety of atypical and other antipsychotic agents

Cytochrome P450 (CYP) drug oxidases play a pivotal role in the elimination of antipsychotic agents, and therefore influence the toxicity and efficacy of these drugs. Factors that affect CYP function and expression have a major impact on treatment outcomes with antipsychotic agents. In particular, aspects of CYP pharmacogenetics, and the processes of CYP induction and inhibition all influence in-vivo rates of drug elimination. Certain CYPs that mediate the oxidation of antipsychotic drugs exhibit genetic variants that may influence in-vivo activity. Thus, single nucleotide polymorphisms (SNPs) in CYP genes have been shown to encode enzymes that have decreased drug oxidation capacity. Additionally, psychopharmacotherapy has the potential for drug-drug inhibitory interactions involving CYPs, as well as drug-mediated CYP induction. Literature evidence supports a role for CYP1A2 in the clearance of the atypical antipsychotics clozapine and olanzapine; CYP1A2 is inducible by certain drugs and environmental chemicals. Recent studies have suggested that specific CYP1A2 variants possessing individual SNPs, and possibly also SNP combinations (haplotypes), in the 5′-regulatory regions may respond differently to inducing chemicals. CYP2D6 is an important catalyst of the oxidation of chlorpromazine, thioridazine, risperidone and haloperidol. Certain CYP2D6 allelic variants that encode enzymes with decreased drug oxidation capacity are more common in particular ethnic groups, which may lead to adverse effects with standard doses of psychoactive drugs. Thus, genotyping may be useful for dose optimization with certain psychoactive drugs that are substrates for CYP2D6. However, genotyping for inducible CYPs is unlikely to be sufficient to direct therapy with all antipsychotic agents. In-vivo CYP phenotyping with cocktails of drug substrates may assist at the commencement of therapy, but this approach could be complicated by pharmacokinetic interactions if applied when an antipsychotic drug regimen is ongoing.

Trial of aripiprazole in the treatment of first-episode schizophrenia

AIMS

Aripiprazole is an atypical antipsychotic indicated for the treatment of adult patients with schizophrenia. It is effective and well tolerated in patients with schizophrenia or schizoaffective disorder. The aim of the present study was to investigate therapeutic efficacy and tolerability of aripiprazole in patients with first-episode schizophrenia.

METHODS

Twenty-one patients meeting the DSM-IV criteria for schizophrenia were recruited. The Positive and Negative Symptom Scale (PANSS) and the Clinical Global Impressions Scale (CGI) were completed at the beginning of the study and again after 1, 2, 4, and 8 weeks of aripiprazole treatment. Side-effects were analyzed using the Udvalg for Kliniske Undersøgelser Side-Effect Rating Scale. Weight was checked at each testing session, and prolactin levels were measured at baseline and after 8 weeks of aripiprazole treatment.

RESULTS

Significant benefits were observed after the first week of treatment. After 1 week of aripiprazole treatment, subscale and total scores on the PANSS had decreased significantly. This significant decrease was maintained throughout the study period. The mean score of CGI severity was also significantly different after 2 weeks of aripiprazole administration when compared to baseline score, and the significance was maintained thereafter. Weight did not significantly change after aripiprazole administration. Although mean prolactin level was decreased at 8 weeks, the difference was not significant.

CONCLUSIONS

Aripiprazole is an effective and well-tolerated antipsychotic agent in patients with first-episode schizophrenia. Further investigations with larger samples are needed.

WS-50030 [7-{4-[3-(1H-inden-3-yl)propyl]piperazin-1-yl}-1,3-benzoxazol-2(3H)-one]: a novel dopamine D2 receptor partial agonist/serotonin reuptake inhibitor with preclinical antipsychotic-like and antidepressant-like activity

The preclinical characterization of WS-50030 [7-{4-[3-(1H-inden-3-yl)propyl]piperazin-1-yl}-1,3-benzoxazol-2(3H)-one] is described. In vitro binding and functional studies revealed highest affinity to the D(2) receptor (D(2L) K(i), 4.0 nM) and serotonin transporter (K(i), 7.1 nM), potent D(2) partial agonist activity (EC(50), 0.38 nM; E(max), 30%), and complete block of the serotonin transporter (IC(50), 56.4 nM). Consistent with this in vitro profile, WS-50030 (10 mg/kg/day, 21 days) significantly increased extracellular 5-HT in the rat medial prefrontal cortex, short-term WS-50030 treatment blocked apomorphine-induced climbing (ID(50), 0.51 mg/kg) in a dose range that produced minimal catalepsy in mice and induced low levels of contralateral rotation in rats with unilateral substantia nigra 6-hydroxydopamine lesions (10 mg/kg i.p.), a behavioral profile similar to that of the D(2) partial agonist aripiprazole. In a rat model predictive of antipsychotic-like activity, WS-50030 and aripiprazole reduced conditioned avoidance responding by 42 and 55% at 10 mg/kg, respectively. Despite aripiprazole's reported lack of effect on serotonin transporters, long-term treatment with aripiprazole or WS-50030 reversed olfactory bulbectomy-induced hyperactivity at doses that did not reduce activity in sham-operated rats, indicating antidepressant-like activity for both compounds. Despite possessing serotonin reuptake inhibitory activity in addition to D(2) receptor partial agonism, WS-50030 displays activity in preclinical models predictive of antipsychotic- and antidepressant efficacy similar to aripiprazole, suggesting potential efficacy of WS-50030 versus positive and negative symptoms of schizophrenia, comorbid mood symptoms, bipolar disorder, major depressive disorder, and treatment-resistant depression. Furthermore, WS-50030 provides a tool to further explore how combining these mechanisms might differentiate from other antipsychotics or antidepressants.

Role of serotonin via 5-HT2B receptors in the reinforcing effects of MDMA in mice

The amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) reverses dopamine and serotonin transporters to produce efflux of dopamine and serotonin, respectively, in regions of the brain that have been implicated in reward. However, the role of serotonin/dopamine interactions in the behavioral effects of MDMA remains unclear. We previously showed that MDMA-induced locomotion, serotonin and dopamine release are 5-HT_2B receptor-dependent. The aim of the present study was to determine the contribution of serotonin and 5-HT_2B receptors to the reinforcing properties of MDMA.

We show here that 5-HT_2B^−/− mice do not exhibit behavioral sensitization or conditioned place preference following MDMA (10 mg/kg) injections. In addition, MDMA-induced reinstatement of conditioned place preference after extinction and locomotor sensitization development are each abolished by a 5-HT_2B receptor antagonist (RS127445) in wild type mice. Accordingly, MDMA-induced dopamine D1 receptor-dependent phosphorylation of extracellular regulated kinase in nucleus accumbens is abolished in mice lacking functional 5-HT_2B receptors. Nevertheless, high doses (30 mg/kg) of MDMA induce dopamine-dependent but serotonin and 5-HT_2B receptor-independent behavioral effects.

These results underpin the importance of 5-HT_2B receptors in the reinforcing properties of MDMA and illustrate the importance of dose-dependent effects of MDMA on serotonin/dopamine interactions.

Polymorphism of human cytochrome P450 enzymes and its clinical impact

Pharmacogenetics is the study of how interindividual variations in the DNA sequence of specific genes affect drug response. This article highlights current pharmacogenetic knowledge on important human drug-metabolizing cytochrome P450s (CYPs) to understand the large interindividual variability in drug clearance and responses in clinical practice. The human CYP superfamily contains 57 functional genes and 58 pseudogenes, with members of the 1, 2, and 3 families playing an important role in the metabolism of therapeutic drugs, other xenobiotics, and some endogenous compounds. Polymorphisms in the CYP family may have had the most impact on the fate of therapeutic drugs. CYP2D6, 2C19, and 2C9 polymorphisms account for the most frequent variations in phase I metabolism of drugs, since almost 80% of drugs in use today are metabolized by these enzymes. Approximately 5-14% of Caucasians, 0-5% Africans, and 0-1% of Asians lack CYP2D6 activity, and these individuals are known as poor metabolizers. CYP2C9 is another clinically significant enzyme that demonstrates multiple genetic variants with a potentially functional impact on the efficacy and adverse effects of drugs that are mainly eliminated by this enzyme. Studies into the CYP2C9 polymorphism have highlighted the importance of the CYP2C9*2 and *3 alleles. Extensive polymorphism also occurs in other CYP genes, such as CYP1A1, 2A6, 2A13, 2C8, 3A4, and 3A5. Since several of these CYPs (e.g., CYP1A1 and 1A2) play a role in the bioactivation of many procarcinogens, polymorphisms of these enzymes may contribute to the variable susceptibility to carcinogenesis. The distribution of the common variant alleles of CYP genes varies among different ethnic populations. Pharmacogenetics has the potential to achieve optimal quality use of medicines, and to improve the efficacy and safety of both prospective and currently available drugs. Further studies are warranted to explore the gene-dose, gene-concentration, and gene-response relationships for these important drug-metabolizing CYPs.

The International Society for Bipolar Disorders (ISBD) consensus guidelines for the safety monitoring of bipolar disorder treatments

OBJECTIVES

Safety monitoring is an important aspect of bipolar disorder treatment, as mood-stabilising medications have potentially serious side effects, some of which may also aggravate existing medical comorbidities. This paper sets out the International Society for Bipolar Disorders (ISBD) guidelines for the safety monitoring of widely used agents in the treatment of bipolar disorder. These guidelines aim to provide recommendations that take into consideration the balance between safety and cost-effectiveness, to highlight iatrogenic and preventive clinical issues, and to facilitate the broad implementation of therapeutic safety monitoring as a standard component of treatment for bipolar disorder.

METHODS

These guidelines were developed by an ISBD workgroup, headed by the senior author (MB), through an iterative process of serial consensus-based revisions. After this, feedback from a multidisciplinary group of health professionals on the applicability of these guidelines was sought to develop the final recommendations.

RESULTS

General safety monitoring recommendations for all bipolar disorder patients receiving treatment and specific monitoring recommendations for individual agents are outlined.

CONCLUSIONS

These guidelines are derived from evolving and often indirect data, with minimal empirical cost-effectiveness data available to provide guidance. These guidelines will therefore need to be modified to adapt to different clinical settings and health resources. Clinical acumen and vigilance remain critical ingredients for safe treatment practice.

Practical guidelines for the use of new generation antipsychotic drugs (except clozapine) in adult individuals with intellectual disabilities

New generation antipsychotic (NGA) drugs introduced to the US market after clozapine (aripiprazole, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) are frequently used in individuals with intellectual disabilities (ID). However, there is very limited research to fully establish evidence-based or personalized medicine approaches for their use in this population. These guidelines take a pragmatic approach to establishing frameworks for their use by utilizing the prescribing information and reviewing the available literature on other relevant neuropsychiatric disorders. In the absence of expert consensus guidance and well-controlled comparison trials, we present a set of guidelines to inform initiation, dosing and monitoring of use in adults. Further, in these guidelines we provide practical information on drug-drug interactions and adverse drug reactions, and a brief review of discontinuation syndromes, potential for abuse, use during pregnancy and cost considerations. We also provide drug utilization review forms for each NGA to facilitate implementation of these guidelines, these guidelines provide a practical and necessary resource for practitioners treating psychiatric disorders and challenging behaviors in adult individuals with ID.

Aripiprazole brain concentration is altered in P-glycoprotein deficient mice

P-glycoprotein (P-gp) is a transporter that mediates the tissue disposition of numerous drugs. To evaluate the role of P-glycoprotein (P-gp) in aripiprazole tissue distribution and penetration across the blood-brain barrier, mice deficient in the P-gp gene (Abcb1a/b-/-) were dosed intraperitoneally with 2 microg/g mouse of the antipsychotic drug aripiprazole. Wildtype FVB mice were administered the same dose as transgenic animals. At one, two, and three hours after dosing, blood and tissue samples were collected and assayed for aripiprazole concentration by HPLC. Deficiency of P-gp did not result in significantly altered plasma drug concentrations but had dramatic effects on drug concentrations in brain tissue. At 1, 2, and 3 h after dosing, aripiprazole brain concentrations in the Abcb1a/b-/- mice were 4.6-, 4.1- and 3.0-fold higher, respectively (P<0.01), compared with the wildtype mice. Increases in drug concentration were also observed in testes and muscle in Abcb1a/b -/- mice. All other tissues including gut, lung, heart, kidney, liver, and spleen did not show significant differences between the two groups. These data provide evidence that aripiprazole is a transportable substrate of P-gp. Thus, factors influencing P-gp activity within the blood brain barrier in humans may have implications for the therapeutic effects and tolerability of aripiprazole.

A non-randomized study to investigate the effects of the atypical antipsychotic aripiprazole on the steady-state pharmacokinetics of lamotrigine in patients with bipolar I disorder

OBJECTIVE

To determine the effect of aripiprazole on steady-state pharmacokinetics of lamotrigine in patients with bipolar I disorder who were clinically stable on lamotrigine (100-400 mg/day) for >or=4 weeks.

METHODS

In this open-label study, aripiprazole was administered at 10 mg/day for 3 days, 20 mg/day for 3 days, then 30 mg/day for 8 days. Blood samples were collected on Days -1 and 14 for determination of lamotrigine steady-state pharmacokinetic parameters. Safety and tolerability were assessed.

RESULTS

Eighteen patients were administered aripiprazole in combination with lamotrigine. Geometric mean (GM) values for lamotrigine maximum plasma concentration were similar for lamotrigine alone (26 ng/mL) and with co-administered aripiprazole (23 ng/mL). GM values for plasma lamotrigine area under the concentration-time curve (AUCtau) were comparable for lamotrigine alone (434 ng/h/mL) and with co-administered aripiprazole (394 ng/h/mL). Median T(max) of lamotrigine alone and combined with aripiprazole was 1.98 and 0.77 h, respectively. No changes to lamotrigine dose-normalized plasma trough concentrations were observed with co-administered aripiprazole. Sixteen patients (88.9%) experienced >or=1 adverse event (AE), the most common of which was insomnia (n = 6).

CONCLUSIONS

Aripiprazole had no meaningful effect on lamotrigine steady-state pharmacokinetics in patients with bipolar I disorder. No dosage adjustment of lamotrigine is required and the combination was generally safe and well tolerated.

Aripiprazole: in major depressive disorder

Aripiprazole, an oral quinolinone, is the first atypical antipsychotic agent to be approved in the US as adjunctive treatment in adult patients with major depressive disorder (MDD). In two large, well-designed trials in patients with MDD who had an inadequate response to standard antidepressant therapy, 6 weeks' adjunctive therapy with aripiprazole 2-20 mg/day improved mean Montgomery Asberg Depression Rating Scale (MADRS) total scores (primary endpoint) to a significantly greater extent than adjunctive placebo treatment. Improvements in mean MADRS total score during the double-blind phase favoured adjunctive aripiprazole treatment from 1-2 weeks onward, with per-protocol subgroup analyses showing that mean changes were not affected by the specific standard antidepressant therapy used, age or sex of the patient or the mean MADRS total scores at the start of double-blind adjunctive therapy. In general, secondary endpoint scores, including those for the Sheehan Disability Scale, Clinical Global Impression (CGI) Improvement scale and CGI Severity of Illness scale, improved to a significantly greater extent with adjunctive aripiprazole than with adjunctive placebo treatment, with significantly higher response and remission rates in the aripiprazole groups. In these two pivotal trials, adjunctive aripiprazole 2-20 mg/day was generally well tolerated, with most treatment-emergent adverse events being of mild to moderate severity.