Aripiprazole attenuates the discriminative-stimulus and subject-rated effects of D-amphetamine in humans

The results of animal research suggest that the use of partial agonists at dopamine (DA) D2 receptors may be an effective strategy for the treatment of stimulant dependence. Aripiprazole is an atypical antipsychotic that has partial agonist activity at D2 receptors. In this experiment, seven human participants with a history of nontherapeutic stimulant use learned to discriminate 15 mg oral D-amphetamine. After acquiring the discrimination (ie > or =80% correct responding on four consecutive sessions), the effects of a range of doses of D-amphetamine (0, 2.5, 5, 10, and 15 mg), alone and in combination with aripiprazole (0 and 20 mg), were assessed. D-Amphetamine alone functioned as a discriminative stimulus, produced prototypical subject-rated drug effects (eg increased ratings of Active, Alert, Energetic) and elevated cardiovascular indices. These effects were generally a function of dose. Aripiprazole alone did not occasion D-amphetamine-appropriate responding or produce subject-rated effects, but modestly impaired performance. Administration of aripiprazole significantly attenuated the discriminative-stimulus and cardiovascular effects of D-amphetamine, as well as some of the subject-rated drug effects. These data are consistent with previous preclinical findings and suggest that DA partial agonists deserve further evaluation as potential pharmacotherapies in the management of stimulant dependence. Future studies should investigate the ability of aripiprazole or related compounds to attenuate the behavioral effects of stimulants associated with a greater degree of dependence, such as methamphetamine or cocaine, in dependent individuals.

Second generation antipsychotics--aripiprazole revisited

Six second-generation antipsychotics are marketed in the US. Is aripiprazole as effective as the others and better tolerated?

[Suicidal ideations and suicide attempts after starting on aripiprazole, a new antipsychotic drug]

In 5 patients, 3 women aged 30, 32 and 41 years and 2 men aged 36 and 56 years, serious side effects developed after starting aripiprazole, a new antipsychotic drug. 2 patients had not been treated with antipsychotic drugs before, while in 3 there was a switch in antipsychotic treatment. The side effects consisted primarily oftroubling feelings ofagitation, akathisia, insomnia and dysphoria. 3 of the patients made a suicide attempt and 2 developed suicidal thoughts. The patients had not previously attempted suicide and the suicidal thoughts disappeared after discontinuation ofaripiprazole. Suicidal tendencies have not been reported before as a side effect ofaripiprazole.

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.

Tardive dyskinesia in the era of typical and atypical antipsychotics. Part 2: Incidence and management strategies in patients with schizophrenia

OBJECTIVE

Tardive dyskinesia (TD), the principal adverse effect of long-term conventional antipsychotic treatment, can be debilitating and, in many cases, persistent. We sought to explore the incidence and management of TD in the era of atypical antipsychotics because it remains an important iatrogenic adverse effect.

METHODS

We conducted a review of TD incidence and management literature from January 1, 1965, to January 31, 2004, using the terms tardive dyskinesia, management, therapy, neuroleptics, antipsychotics, clozapine, olanzapine, risperidone, quetiapine, ziprasidone, and aripiprazole. Additional articles were obtained by searching the bibliographies of relevant references. We considered articles that contributed to the current understanding of both the incidence of TD with atypical antipsychotics and management strategies for TD.

RESULTS

The incidence of TD is significantly lower with atypical, compared with typical, antipsychotics, but cases of de novo TD have been identified. Evidence suggests that atypical antipsychotic therapy ameliorates long-standing TD. This paper outlines management strategies for TD in patients with schizophrenia.

CONCLUSION

The literature supports the recommendation that atypical antipsychotics should be the first antipsychotics used in patients who have experienced TD as a result of treatment with conventional antipsychotic agents. The other management strategies discussed may prove useful in certain patients.

Aripiprazole for the treatment of psychosis in patients with Alzheimer's disease: a randomized, placebo-controlled study

This study compared the efficacy, safety, and tolerability of aripiprazole, a novel antipsychotic, with placebo in patients with psychosis associated with Alzheimer's Disease (AD). This 10-week, double-blind, multicenter study randomized 208 outpatients (mean age, 81.5 years) with AD-associated psychosis to aripiprazole (n = 106) or placebo (n = 102). The initial aripiprazole dose of 2 mg/d was titrated upwards (5, 10, or 15 mg/d) according to efficacy and tolerability. Evaluations included Neuropsychiatric Inventory (NPI) Psychosis subscale and Brief Psychiatric Rating Scale (BPRS), adverse event (AE) reports, extrapyramidal symptoms (EPS) rating scales, and body weight. Overall, 172 patients (83%) completed the study. Mean aripiprazole dose at end point was 10.0 mg/d. The NPI Psychosis subscale score showed improvements in both groups (aripiprazole, -6.55; placebo, -5.52; P = 0.17 at end point). Aripiprazole-treated patients showed significantly greater improvements from baseline in BPRS Psychosis and BPRS Core subscale scores at end point compared with placebo. AEs were generally mild to moderate in severity and included (aripiprazole vs. placebo): urinary tract infection (8% vs. 12%), accidental injury (8% vs. 5%), somnolence (8% vs. 1%), and bronchitis (6% vs. 3%). Somnolence was mild and not associated with falls or accidental injury. There were no significant differences from placebo in EPS scores, or clinically significant ECG abnormalities, vital signs, or weight. In conclusion, aripiprazole showed similar improvements to placebo in psychotic symptoms as assessed by NPI Psychosis subscale scores, but significantly greater effects on BPRS Core and Psychosis assessments in community-living AD patients with psychosis. Aripiprazole was safe and well tolerated in this patient population.

Aripiprazole augmentation of selective serotonin reuptake inhibitors for treatment-resistant major depressive disorder

BACKGROUND

Due to their favorable side effect profile, atypical antipsychotic agents offer important therapeutic advantages in mood disorders. Aripiprazole, an atypical antipsychotic agent with partial dopaminergic and serotonin 1A receptor agonist activity, may be particularly useful when used in conjunction with standard antidepressants in treatment-resistant depression. The purpose of this study was to test this hypothesis in depressed outpatients who have not experienced significant clinical improvement following an adequate trial of a selective serotonin reuptake inhibitor (SSRI).

METHOD

12 patients (mean +/- SD age = 46.6 +/- 11.3 years, 66.7% female) with major depressive disorder (MDD) diagnosed by use of the Structured Clinical Interview for DSM-IV-Axis I Disorders, who had failed to experience a clinical response following an adequate trial of an SSRI, were treated with open-label aripiprazole in addition to their SSRI for 8 weeks. Clinical response was defined as a 50% or greater decrease in depressive symptoms during the course of the trial (baseline-endpoint) as measured by the 17-item Hamilton Rating Scale for Depression total score. Data were collected from August 2003 to July 2004.

RESULTS

9/12 (75.0%) patients completed the trial. Using a completer analysis, 5/9 (55.6%) patients were classified as responders. An intent-to-treat (ITT) analysis resulted in 7 responders (58.3%). The overall proportion of remitters was 3/9 (33.3%) using a completer analysis and 5/12 (41.7%) using the ITT analysis. Aripiprazole administration appeared safe, with no severe adverse events observed in any of the study participants.

CONCLUSIONS

These results suggest a possible augmentation role for aripiprazole when used in conjunction with SSRIs in SSRI-resistant MDD.

Diabetic ketoacidosis associated with aripiprazole

BACKGROUND

Atypical antipsychotics have become the mainstay of management of schizophrenia and other psychotic disorders due to low risk of extrapyramidal symptoms. However, postmarketing data has reported atypical antipsychotic agents being associated with hyperglycaemia and diabetic ketoacidosis (DKA). We believe this to be the first published report of hyperglycaemia and DKA with the newest atypical antipsychotic agent, aripiprazole.

CASE REPORT

A 34-year-old African-American female with schizophrenia presented to the emergency department with nausea, vomiting, and malaise for 3-4 days shortly after initiation of aripiprazole therapy. Initial laboratory results revealed significant hyperglycaemia with metabolic acidosis. The patient received treatment for DKA with an intravenous insulin infusion and fluid replacement. Isophane insulin suspension (NPH insulin) was begun immediately following the insulin drip and continued upon discharge from the hospital. Outpatient follow-up information was not available.

CONCLUSION

To our knowledge, this is the first case report of aripiprazole associated with hyperglycaemia and DKA. This case is striking in that DKA occurred 4 days following initiation of aripiprazole and the patient had rapid resolution of symptoms and normalization of laboratory values upon discontinuation of aripiprazole. It is important that health-care providers monitor for hyperglycaemia when prescribing atypical antipsychotics including aripiprazole.

Aripiprazole increases dopamine but not noradrenaline and serotonin levels in the mouse prefrontal cortex

Aripiprazole, a novel atypical antipsychotic drug, can significantly increase dopamine (DA) levels in the prefrontal cortex of rats, but only at low doses below 1mg/kg. The aim of the present work was to test the effect of aripiprazole (0, 0.1, 0.3, 3 and 30 mg/kg, i.p.) on extracellular levels of monoamines in the prefrontal cortex of freely moving C57BL/6J mice. Concurrent horizontal locomotor activity was also assessed. Aripiprazole produced a significant increase in dialysate DA levels after the administration of a low dose of 0.3mg/kg. Lower (0.1 mg/kg) or higher (3 and 30 mg/kg) doses failed to affect extracellular levels of DA. In addition, none of the doses tested in the present study produced significant changes in extracellular levels of noradrenaline (NA) and serotonin (5-HT). For the sake of comparison, clozapine (0, 3 and 10 mg/kg, s.c.) was also tested under similar conditions. Clozapine produced a dose-dependent increase in both dialysate DA and NA levels without affecting extracellular 5-HT. Locomotor activity was significantly decreased by both clozapine and aripiprazole. These data further support the hypothesis that selective activation of dopaminergic neurotransmission in the prefrontal cortex may contribute to the therapeutic efficacy of aripiprazole.

Aripiprazole augmentation of antidepressants for the treatment of partially responding and nonresponding patients with major depressive disorder

OBJECTIVE

To determine the efficacy and tolerability of aripiprazole, a dopamine D2 and 5-HT1A receptor partial agonist, as augmentation of antidepressant treatment of partially responding and nonresponding patients with major depressive disorder.

METHOD

Fifteen patients with major depressive disorder (diagnosed with a site-generated form described in the text) and an incomplete response or no response to > or = 8 weeks of antidepressant (selective serotonin reuptake inhibitor, venlafaxine, or bupropion) monotherapy were treated with aripiprazole augmentation in an 8-week, open-label study. Data were gathered from July 2003 to March 2004.

RESULTS

The mean duration of antidepressant monotherapy at baseline was 43.1 weeks. At baseline, mean Clinical Global Impressions-Severity of Illness scale and Hamilton Rating Scale for Depression (HAM-D) scores were 4.3 and 18.9, respectively. After initiation of aripiprazole augmentation, 6 of 15 patients achieved remission (HAM-D score < or = 7) at week 1, and 9 of 15 patients remitted by week 2. All 8 completers achieved remission by study endpoint. Akathisia in 2 patients who withdrew prematurely prompted a reduction in the starting dose of aripiprazole from 10 mg/day to 2.5 mg/day, resulting in a 50% reduction in attrition due to akathisia (2/7 withdrew due to akathisia with the 10-mg starting dose, 1/8 withdrew due to akathisia with the 2.5-mg starting dose). Discontinuation rates after 4 weeks of treatment were lower for the 2.5-mg starting dose (1/8 patients) than for the 10-mg starting dose (3/7 patients). Overall discontinuation rates at endpoint were lower for the 2.5-mg dose (3/8 patients) than the 10-mg dose (4/7 patients). Response to aripiprazole augmentation did not appear to be related to the antidepressant used at study initiation.

CONCLUSION

Aripiprazole is an effective augmentation strategy for improving therapeutic response in patients with treatment-resistant major depressive disorder when administered in combination with standard antidepressant therapy. Based on this clinical signal, a double-blind, placebo-controlled trial is warranted.

Characterisation of olanzapine-induced weight gain and effect of aripiprazole vs olanzapine on body weight and prolactin secretion in female rats

RATIONALE

Atypical antipsychotic drug (APD)-induced weight gain causes non-compliance, increasing the risk of relapse and medical complications.

OBJECTIVES

In an animal model, we assessed body weights, food intake, body fat/lean body mass contents and blood serum levels of glucose and lipids in female rats treated with olanzapine (Experiment 1). Also, we investigated the effect of aripiprazole vs olanzapine treatment on weight gain (WG) and plasma prolactin secretion in two strains (Wistar and Sprague-Dawley) and in two housing conditions (singly and group housed; Experiment 2).

METHODS

In Experiment 1, Wistar females received either vehicle or olanzapine (5.0 mg kg(-1), p.o.) twice daily for 14 days. In Experiment 2, female rats (Wistar or Sprague-Dawley), housed singly or in groups, received either vehicle, aripiprazole (2.0-8.0 mg kg(-1), p.o.), or olanzapine (1.0-10 mg kg(-1), p.o.) twice daily for 7 days. Body weights and food intake were assessed daily. Body composition and blood assays were analyzed at the end of the treatment.

RESULTS

WG induced by chronic olanzapine treatment was characterised by hyperphagia, increased body fat, and serum free fatty acid content and reduced lean tissue and serum glucose content. Subchronic aripiprazole treatment resulted in rapid and robust WG similar to those observed with olanzapine. In spite of similar effects on body weight, aripiprazole and olanzapine stimulated markedly different patterns of prolactin secretion. Body weight changes and prolactin secretion induced by these APDs were significantly modulated by housing and by strain.

CONCLUSION

Assessment of body weight in the present model may not have predictive validity, and other measures may be needed to differentiate between WG-inducing and weight-neutral drugs.

Synthesis of Biologically Active Amines via Rhodium−Bisphosphite-Catalyzed Hydroaminomethylation

[reaction: see text] We report the use of a highly regioselective rhodium-bisphosphite catalyst for olefin hydroaminomethylation. This catalyst system was successfully applied in the synthesis of two biologically active tertiary amines, ibutilide and aripiprazole.

Aripiprazole for agitation in a 13-year-old girl with neuroleptic malignant syndrome

Neuroleptic Malignant Syndrome (NMS) rarely results from atypical antipsychotic therapy. To date, no information is available on the incidence of NMS with aripiprazole, a newer neuroleptic.

OBJECTIVE

To examine the results of a trial of aripiprazole administered to a 13-year-old Mexican-American girl during the course of NMS.

METHODS

Vital signs and laboratory values obtained before and during the aripiprazole trial were compared.

RESULTS

Aripiprazole administration resulted in a mild increase in tachycardia and brief worsening of serum creatinine kinase level, but did not significantly affect temperature, respiratory rate, or blood pressure.

CONCLUSIONS

In this adolescent with NMS, aripiprazole treatment was associated with a mild worsening of symptoms.

Clozapine-Induced Hyperlipidemia Resolved After Switch to Aripiprazole Therapy

OBJECTIVE:

To report a case of severe clozapine-induced hypercholesterolemia and hypertriglyceridemia that resolved after therapy was switched to aripiprazole.

CASE SUMMARY:

A 42-year-old white man with schizoaffective disorder experienced new-onset hyperlipidemia with the addition of clozapine therapy. Despite treatment with various antihyperlipidemic agents, his total cholesterol level reached 477 mg/dL and his triglyceride level reached 4758 mg/dL. After a decrease in adherence with clozapine and subsequent deterioration, the patient was hospitalized and his antipsychotic therapy was switched to aripiprazole. The patient's lipid levels improved dramatically to the point that antihyperlipidemic treatment was discontinued. Due to lack of adequate symptomatic relief of psychiatric symptoms, the patient was ultimately switched back to clozapine therapy, at which time his lipid levels started to worsen again.

DISCUSSION:

There is a critical scarcity of data that relate to aripiprazole-induced lipid changes. Some studies have suggested that aripiprazole is not associated with the development of hyperlipidemia. Our case indicates that aripiprazole therapy may not have an adverse effect on lipid levels, even in patients who have a history of hyperlipidemia induced by another atypical antipsychotic.

CONCLUSIONS:

Should aripiprazole be found to have a definitive lipid-neutral effect, then clinicians would be wise to factor this finding into overall benefit-versus-risk considerations in the antipsychotic treatment selection process, especially in a society in which cardiovascular disease continues to be a principal cause of morbidity and mortality.

Effects of novel antipsychotics, amisulpiride and aripiprazole, on maternal behavior in rats

RATIONALE

Rat maternal behavior, which entails complex motivational and social factors, is disrupted by the currently available typical and atypical antipsychotics. It is thought that this disruption reflects a side effect of antipsychotics, modeling the neuroleptic-induced negative or deficit state. Amisulpiride and aripiprazole are new atypical antipsychotics with mechanisms of action distinct from the current typical and atypical antipsychotics. The effects of these drugs on maternal behavior have not been explored.

OBJECTIVE

In the present study, we systematically examined the behavioral effects of amisulpiride and aripiprazole on maternal behavior in postpartum female rats.

METHODS

Various components of maternal behavior (pup retrieval, pup licking, nest building and pup nursing) were examined repeatedly over a period of 24 h after a single injection of three doses of amisulpiride (10, 30, and 100 mg/kg s.c.) and aripiprazole (3, 10, and 30 mg/kg).

RESULTS

Amisulpiride at the lower doses (10 and 30 mg/kg) enhanced pup licking, and only at the highest dose disrupted the active components of maternal behavior such as pup retrieval and nest building. Its effect was delayed in onset and prolonged as compared to other antipsychotics. Aripiprazole, even at the highest dose (30 mg/kg) did not impair pup retrieval or pup licking. However, it did disrupt nest building and led to enhanced pup nursing.

CONCLUSIONS

The unique effects of these two drugs may be due to their unique actions at the mesolimbic dopamine synapses. The sparing of the major components of maternal behavior by aripiprazole may be related to its partial agonist effects, whereas the enhancement of pup licking by amisulpiride may be related to its dose-dependent preferential effect on the presynaptic autoreceptors. The potential clinical implications of these findings are discussed.

Effectiveness of aripiprazole v. haloperidol in acute bipolar mania: double-blind, randomised, comparative 12-week trial

BACKGROUND

Despite several treatmentoptions, adherenceto therapy is poor in patients with bipolar disorder.

AIMS

A double-blind, controlled comparison of aripiprazole and haloperidol in patients with bipolar I disorder experiencing acute manic or mixed episodes.

METHOD

Patients (n=347) were randomised to receive aripiprazole or haloperidol in this 12-week, multicentre study. The primary outcome measure was the number of patients in response (greater, similar 50% improvement from baseline in Young Mania Rating Scale score) and receiving therapy at week 12.

RESULTS

At week 12, significantly more patients taking aripiprazole (49.7%) were in response and receiving therapy compared with those taking haloperidol (28.4%; P < 0.001). Continuation rates differed markedly between treatments (week 12: aripiprazole, 50.9%; haloperidol, 29.1%). Extrapyramidal adverse events were more frequent with haloperidol than aripiprazole (62.7% v. 24.0%).

CONCLUSIONS

Aripiprazole showed superior levels of response and tolerability to haloperidol in the treatment of an acute manic episode for up to 12 weeks.

Aripiprazole's low intrinsic activities at human dopamine D2L and D2S receptors render it a unique antipsychotic

Aripiprazole is the first clinically approved atypical antipsychotic agent having dopamine D2 receptor partial agonist activities. To evaluate aripiprazole's agonist and antagonist properties, we established a Chinese hamster ovary cell line expressing high and low densities of the long and short isoforms of human dopamine D2 receptors, then compared its properties with 7-{3-[4-(2,3-dimethylphenyl)piperazinyl]propoxy}-2(1H)-quinolinone (OPC-4392), S(-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine ((-)-3-PPP), and terguride (other partial agonists) using forskolin-stimulated cAMP accumulation as an index. In cells expressing high receptor densities, all partial agonists predominantly behaved as agonists. However, in cells expressing low receptor densities, the partial agonists showed significantly lower maximal effects than dopamine. Aripiprazole showed the lowest intrinsic activities. In addition, all compounds blocked the action of dopamine with a maximum effect equal to that of each compound alone. Aripiprazole's low intrinsic activities may account for the clinical finding that, unlike the other partial agonists, it is substantially active against both positive and negative symptoms of schizophrenia.

Development and validation of an LC–MS/MS method for the quantitative determination of aripiprazole and its main metabolite, OPC-14857, in human plasma

An accurate, sensitive, reproducible, and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for determination of aripiprazole and its main metabolite, OPC-14857, in human plasma was developed and validated. Chromatographic separation was achieved isocratically on a C18 reversed-phase column within 7.5 min. The calibration curve, ranging from 0.1 to 100 ng/ml, was fitted to a 1/y2-weighted linear regression model. The assay showed no significant interference. Lower limit of quantitation (LLOQ) for both analytes was 0.1 ng/ml using 0.4 ml of plasma. Intra- and inter-assay precision and accuracy values for aripiprazole and OPC-14857 were within regulatory limits.

Aripiprazole in schizophrenia with cocaine dependence: a pilot study

The debilitation of schizophrenia (SCHZ) worsens markedly with comorbid cocaine dependence (CD) and alcohol abuse. To date, no medications have conclusively demonstrated effects against both SCHZ and CD (SCHZ + CD) simultaneously. Because of its dopamine-modulating properties, we hypothesized that aripiprazole would alleviate cocaine craving in patients with SCHZ + CD. We conducted a prospective, 8-week, open-label trial in poorly compliant SCHZ + CD subjects. Each received aripiprazole as their sole neuroleptic agent at a maximum dose of 15 mg/d. The Brief Psychiatric Rating Scale (BPRS) and the Brief Substance Craving Scale (BSCS) measured psychosis and subjective cocaine and alcohol cravings. Urine tests for cocaine provided data on actual use. Of 10 male subjects entered, 6 (60%) completed the 8-week trial. In those cases, positive urine tests dropped significantly (P < 0.001) after 2 weeks, when aripiprazole had reached steady state. Mean cocaine craving scores declined significantly (P = 0.026) as did mean alcohol craving scores (P = 0.006). Declining psychosis scores were associated with declining cocaine craving (r = 0.87, P < 0.01) and alcohol craving (r = 0.88, P < 0.01), respectively. This experience suggests possible aripiprazole effects in lowering both desire for and the use of cocaine in comorbid SCHZ subjects. These data suggest double-blind, randomized, comparison study in this severely ill, comorbid patient group.

['Awakening': a confusing improvement during treatment with atypical antipsychotic agents]

Two schizophrenic women, aged 30 and 40 years, respectively, in whom the symptoms changed after a switch in medication from clozapine to aripiprazole and from olanzapine followed by quetiapine to risperidone, respectively, were initially thought to be experiencing a possible recurrence. After thoughtful consideration, the phenomena, such as disappearance of drowsiness and of loss of energy, in combination with cognitive improvement, could be understood as the result of a dramatic improvement, known as 'awakening'. This had significant consequences for the follow-up since the patients had to deal with new possibilities and emotions.

The treatment of mixed states and the risk of switching to depression

There are few controlled studies evaluating the treatment of bipolar mixed states. Evidence suggests that mixed states may be more responsive to some anticonvulsants than to lithium. Olanzapine alone or in combination with divalproate or lithium has been adequately evaluated in randomized clinical trials involving mixed-state patients, whereas risperidone and quetiapine have not. There is also some evidence demonstrating the efficacy of ziprasidone and aripiprazole. The risk of switching to depression is high in mixed states. Conventional antipsychotics, such as haloperidol, may be less efficacious at protecting against a switch to depression than atypical antipsychotics, divalproate or lithium. When choosing drugs for the treatment of mania, and especially for the treatment of mixed states, their efficacy against manic and depressive symptoms, and their safety in terms of the risk of switching to depression should be taken into account.

TrkB partial agonists: potential treatment strategy for epilepsy, mania, and autism

Brain-derived neurotrophic factor (BDNF) is a member of a family of neurotrophins that, by activating a tyrosine kinase B receptor (TrkB), regulates a wide variety of processes in the nervous system, including neural development, function and survival. Evidence suggests that excess BDNF is involved in the pathogenesis of epilepsy, mania and autism. Thus, agents that can decrease BDNF-TrkB pathway signaling may be therapeutic for these diseases. However, blocking BDNF-TrkB pathways with TrkB antagonists may be harmful, as BDNF-TrkB deficiency has been related to major depression and Alzheimer's disease. A partial agonist is an agent that elicits a maximum response that is less than that of an agonist (e.g., the physiological ligand), so, in the presence of excess full agonist, a partial agonist would act as an antagonist. Interestingly, a dopaminergic partial agonist, aripiprazole, has been successfully developed for the treatment of psychotic disorders. Recently specific TrkB partial agonists have been synthesized by O'Leary and Hughes; it is proposed that these partial TrkB agonists may provide a novel strategy for the treatment of epilepsy, mania or autism, which may be associated with BDNF-TrkB hyperfunction.

Effects of novel antipsychotics with mixed D(2) antagonist/5-HT(1A) agonist properties on PCP-induced social interaction deficits in the rat

Considerable interest has arisen in identifying antipsychotic agents with improved efficacy against negative symptoms, such as social withdrawal. In rats, a social interaction deficit can be induced by the NMDA antagonist phencyclidine (PCP). Here, we examined the effects of antipsychotics, reported to exert dual 5-HT(1A)/D(2) actions, on PCP-induced social interaction deficits. Drugs were administered daily for 3 days in combination with either vehicle or PCP (2.5mg/kg, SC) and social interaction was measured on the last day of drug treatment. Pairs of unfamiliar rats receiving the same treatment were placed in a large open field for 10 min and the number of social behaviors were scored. The results indicate that: (1) PCP significantly reduced social interaction by over 50% compared with vehicle-treated controls; (2) haloperidol (0.0025-0.16 mg/kg, SC) and clozapine (0.04-10mg/kg, IP) did not reverse PCP-induced social interaction deficits; (3) the substituted benzamide remoxipride reversed PCP-induced deficits at 0.63 and 2.5mg/kg (4) the 5-HT(1A) agonist 8-OH-DPAT was inactive (at 0.01-0.63 mg/kg, SC); (5) among compounds reported to exert dual 5-HT(1A)/D(2) actions, SSR181507 (at 0.16 mg/kg, SC) and aripiprazole (at 0.04 and 0.16 mg/kg, IP), but not ziprasidone (0.04-2.5mg/kg, IP), SLV313 (0.0025-0.16 mg/kg, SC) or bifeprunox (0.01-0.63 mg/kg, IP), significantly reversed PCP-induced social interaction deficits; and (6) the 5-HT(1A) receptor antagonist WAY100635 blocked the effects of SSR181507 and aripiprazole. These findings indicate that the balance of activity at 5-HT(1A) and D(2) receptors profoundly influences the activity of antipsychotics in this model of social withdrawal, and their potential benefit on at least some of the negative symptoms of schizophrenia.

Overdose of aripiprazole, a new type of antipsychotic

Aripiprazole is the first member of a new class of antipsychotic medications. Unlike other antipsychotics, it acts as a partial agonist at dopamine D(2) and 5-HT(1A) receptors, thereby mitigating most of the adverse reactions such as extrapyramidal side effects and hyperprolactinemia. Additionally, most research to date has suggested a low incidence of QTc prolongation and orthostatic hypotension at therapeutic doses. Experience in the setting of intentional overdose, however, is limited. We present a case of a 27-year-old woman who intentionally ingested 330 mg of aripiprazole in a suicide attempt. Clinical effects were limited to mild sedation. Serum levels performed by the drug's manufacturer confirmed a total level (parent drug and active metabolite) of 716 ng/mL, nearly six times the upper limit of accepted therapeutic levels. This suggests that aripiprazole's therapeutic index is quite high and reinforces the drug's known safety profile.

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.

Aripiprazole: initial clinical experience with 142 hospitalized psychiatric patients

BACKGROUND

Aripiprazole is the first dopamine D2 receptor partial-agonist approved for treatment of schizophrenia. Its apparently benign adverse-effect profile encourages broader use in other disorders, especially to limit weight gain associated with other antipsychotic or antimanic agents. We considered the first 6 months of experience with aripiprazole in psychiatric inpatients with a range of disorders.

METHODS

We analyzed data obtained from medical records of patients treated with aripiprazole who were hospitalized at McLean Hospital (for 19 +/- 18 days) between December 2002 and June 2003 to evaluate dosing, tolerability, and clinical effects of this new agent in patients diagnosed with DSM-IV psychotic, major affective, or other disorders.

RESULTS

Out of a sample of 2766 adult inpatients (65.5% women), 142 were given aripiprazole (mean final daily dose, 16.1 +/- 6.2 mg, 0.20 +/- 0.09 mg/kg body weight) for major affective disorders (52%), primary psychotic disorders (40%), and dementia (8%). CGI ratings improved by 20% on average. Adverse effects were infrequent (15.5%), were three times more likely among women, and most often involved moderate behavioral activation or nausea, with no new episodes of mania. Of the patients who were given aripiprazole, 83% continued it at discharge. Many patients were obese when they were admitted, and obesity was associated with relatively low mg/kg doses of aripiprazole.

CONCLUSIONS

Aripiprazole was used in a range of disorders and was generally well tolerated. Adverse effects may reflect its unique dopamine partial-agonist activity. Since aripiprazole is likely to be considered for obese patients, body weight should be considered in establishing adequate doses. Controlled trials of this antipsychotic agent in disorders other than schizophrenia are needed.

Aripiprazole in children and adolescents: clinical experience

Despite few supportive data, aripiprazole was being administered to children and adolescents for management of mood instability, aggression, and psychosis. Using a retrospective review (n = 11) and prospective recruitment (n = 6), 17 children and adolescents received aripiprazole 5 to 20 mg/day. Only 4 of 16 bipolar and autistic subjects (25%) demonstrated reduced aggression without adverse events, and the symptoms of 2 of 4 psychotic subjects improved. Coadministration of sedative medications (particularly guanfacine or clonidine) and weight < 58 kg increased the risk of adverse events, such as increased lability and aggression. All three children < 8.6 years old, all four children < 34 kg, and all five children receiving alpha2-agonists developed adverse events prior to clinical efficacy. Age > 11 years, weight > 58 kg, and absence of sedative medications were associated with a 56% (five of nine) success rate. Until larger, prospective studies are completed, caution is advised when considering aripiprazole for smaller children and children receiving sedative medications.

[Aripiprazole in the treatment of schizophrenia]

Seit kurzem ist Aripiprazol zur Behandlung schizophrener Störungen zugelassen. Mit Blick auf seine agonistisch-antagonistischen Eigenschaften an zentralen Dopamin (D2)-Rezeptoren kann es als Vertreter einer neuen Generation von Antipsychotika, den sog. Stabilisatoren des Dopaminsystems, bezeichnet werden. In der Mini-Review werden neurobiologische Aspekte, klinische Wirksamkeit, Pharmakokinetik und Interaktionen sowie unerwünschte Wirkungen knapp beleuchtet.

Switching outpatients with bipolar or schizoaffective disorders and substance abuse from their current antipsychotic to aripiprazole

OBJECTIVE

Substance abuse is extremely common in patients with bipolar disorders, although minimal data are available on the treatment of this important clinical population. Aripiprazole is an atypical antipsychotic that is approved for the treatment of mania and that has a novel mechanism of action, acting as a dopamine-2 receptor partial agonist, thereby increasing dopamine release in some parts of the brain and decreasing dopa-mine release in other brain regions. Dopamine release is implicated in substance use, and both dopaminergic agonists and antagonists have been examined for the treatment of substance abuse. To our knowledge, dopa-mine receptor partial agonists have not been investigated for treatment of substance abuse in humans.

METHOD

Twenty antipsychotic-treated patients with bipolar or schizoaffective disorder and current substance abuse were switched to open-label aripipra-zole using an overlap and taper method. At baseline, diagnoses were confirmed using the Mini-International Neuropsychiatric Interview based on DSM-IV criteria. Psychiatric symptoms, side effects, and substance use and craving were assessed over 12 weeks. Psychiatric symptoms were assessed with the Hamilton Rating Scale for Depression (HAM-D), Young Mania Rating Scale (YMRS), and Brief Psychiatric Rating Scale (BPRS). Substance craving was assessed with visual analogue scales, and side effects were monitored using the Abnormal Involuntary Movement Scale, Simpson-Angus Scale, Barnes Akathisia Scale, and patient report. Study enrollment was from April 2003 to February 2004.

RESULTS

Significant baseline-to-exit improvement in HAM-D (p = .002), YMRS (p = .021), and BPRS (p = .000) scores were observed without a significant change in antipsychotic-induced side effect scales. In 17 participants with current alcohol dependence, significant reductions in dollars spent on alcohol (p = .042) and alcohol craving (p = .003) were found. In 9 participants with cocaine-related disorders, significant reductions in cocaine craving (p = .014), but not use, were found.

CONCLUSION

A change to aripiprazole was associated with symptomatic improvement. Limitations of the study include a small sample size, high attrition, and an open-label design. Controlled trials in dual-diagnosis patients are needed to confirm these findings.

Aripiprazole: an overview of a novel antipsychotic

Aripiprazole exhibits high affinity for dopamine D2 and D3, serotonin 5-HT1A and 5-HT2A receptors, moderate affinity for dopamine D4, serotonin 5-HT2C and 5-HT7, alpha1-adrenergic and histamine H1 receptors. The mean elimination half-lives are about 75 hours and 94 hours for aripiprazole and dehydroaripiprazole, respectively. Steady-state concentrations are attained within 14 days of dosing for both active moieties. At least 1 to 2 weeks, and sometimes up to 4 weeks, may pass before aripiprazole reaches its full effect. The efficacy of aripiprazole was investigated in the treatment of schizophrenia, in the treatment of acute manic episode associated with Bipolar I Disorder, and in the treatment of psychosis associated with Alzheimer's dementia. Aripiprazole has demonstrated superiority to placebo in clinical studies of the treatment of both schizophrenia and acute bipolar mania. Aripiprazole has been evaluated for safety in 5592 patients who participated in multiple dose, premarketing trials in schizophrenia, bipolar mania, and dementia of the Alzheimer's type. The recommended starting and target dose for aripiprazole is 10 or 15 mg/day administered on a once-a-day schedule without regard to meals. Aripiprazole has been systematically evaluated and shown to be effective in a dose range of 10 to 30 mg/day. Dosage increases should not be made before 2 weeks of continuous therapy, the time needed to achieve steady state. At least 1 to 2 weeks, and sometimes up to 4 weeks, may pass before aripiprazole reaches its full effect. In this presentation was given an overview of novel antipsychotic aripiprazole.

The effectiveness and tolerability of aripiprazole for pediatric bipolar disorders: a retrospective chart review

OBJECTIVE

The aim of this retrospective chart review was to evaluate the effectiveness and tolerability of aripiprazole for the treatment of children and adolescents with bipolar disorders.

METHODS

The medical charts of all children and adolescents with a DSM-IV diagnosis of bipolar disorder, type I, type II, not otherwise specified (NOS), or schizoaffective disorder, bipolar type, and who were treated with aripiprazole were reviewed by two child and adolescent psychiatrists who independently confirmed their DSM-IV diagnoses, severity, and the improvement of illness using the Clinical Global Impression (CGI) Severity and Improvement scores for bipolar disorder (CGI-BP) and the Clinical Global Assessment Scale (CGAS).

RESULTS

Thirty patients who were treated with aripiprazole were identified (mean starting dose=9 +/- 4 mg/day, mean final dose=10 +/- 3 mg/day). The overall response rate, defined by a CGI-Improvement score of < or = 2 at endpoint, was 67%. There was a statistically significant improvement in CGAS scores (48 +/- 11 to 65 +/- 11, signed rank = 191, p <0.0001) and CGI-S scores (4.2 +/- 0.8 to 2.8 +/- 1.0, signed rank=-172, p <0.0001, effect size=1.90) from baseline to endpoint. No serious adverse events were identified. Common side effects were sedation (n=10, 33%), akathisia (n=7, 23%), and gastrointestinal disturbances (n=2, 7%). Baseline and endpoint weights were available for 14 (47%) of the patients. Change in weight ranged from +5 to -21 kg and 12 (86%) of 14 patients lost weight (mean weight loss was 3 +/- 6 kg).

CONCLUSIONS

This retrospective chart review suggests that aripiprazole may be effective and well tolerated for children and adolescents with bipolar disorders. Controlled studies of aripiprazole for the treatment of pediatric bipolar disorder are necessary.

Partial dopamine agonists in schizophrenia

The emergence of partial dopamine agonists reinforces the argument for the dopamine hypothesis of schizophrenia. Aripiprazole (Abilify) is the first of these compounds for the treatment of schizophrenia to be launched in the UK. Aripiprazole has a promising efficacy and favourable tolerability profile that suggests it has a significant role to play in the management of schizophrenia.

Clozapine, ziprasidone and aripiprazole but not haloperidol protect against kainic acid-induced lesion of the striatum in mice, in vivo: Role of 5-HT1A receptor activation

Excessive activation of non-NMDA receptors, AMPA and kainate, contributes to neuronal degeneration in acute and progressive pathologies, possibly including schizophrenia. Because 5-HT(1A) receptor agonists have neuroprotective properties (e.g., against NMDA-induced neurotoxicity), we compared the effects of the antipsychotics, clozapine, ziprasidone and aripiprazole, that are partial agonists at 5-HT(1A) receptor, with those of haloperidol, which is devoid of 5-HT(1A) agonist properties, on kainic acid (KA)-induced striatal lesion volumes, in C57Bl/6N mice. The involvement of 5-HT(1A) receptors was determined by antagonist studies with WAY100635, and data were compared with those obtained using the potent and high efficacy 5-HT(1A) receptor agonist, F13714. Intra-striatal KA lesioning and measurement of lesion volumes using cresyl violet staining were carried out at 48 h after surgery. F13714, antipsychotics or vehicle were administered ip twice, 30 min before and 3 1/2 h after KA injection. WAY100635 (0.63 mg/kg) or vehicle were given sc 30 min before each drug injection. Clozapine (2 x 10 mg/kg), ziprasidone (2 x 20 mg/kg) and aripiprazole (2 x 10 mg/kg) decreased lesion volume by 61%, 59% and 73%, respectively. WAY100635 antagonized the effect of ziprasidone and of aripiprazole but only slightly attenuated that of clozapine. In contrast, haloperidol (2 x 0.16 mg/kg) did not affect KA-induced lesion volume. F13714 dose-dependently decreased lesion volume. The 61% decrease of lesion volume obtained with F13714 (2 x 0.63 mg/kg) was antagonized by WAY100635. WAY100635 alone did not affect lesion volume. These results show that 5-HT(1A) receptor activation protects against KA-induced striatal lesions and indicate that some atypical antipsychotic agents with 5-HT(1A) agonist properties may protect against excitotoxic injury, in vivo.

A typical mood stabilizers: a "typical role for atypical antipsychotics

OBJECTIVE

To assess the potential role of atypical antipsychotics as mood stabilizers.

METHOD

A MedLine, PsychLIT, PubMed, and EMBASE literature search of papers published up to December 2004 was conducted using the names of atypical antipsychotics and a number of key terms relevant to bipolar disorder. Additional articles were retrieved by scrutinizing the bibliographies of review papers and literature known to the authors. Data pertinent to the objective was reviewed according to the various phases of bipolar disorder.

RESULTS

The data is most substantive for the use of atypical antipsychotics in mania, to the extent that an argument for a class effect of significant efficacy can be made. This does not extend to bipolar depression, however, good data is now emerging for some agents and will need to be considered for each individual agent as it accumulates. As regards mixed states and rapid cycling the evidence is thus far sparse and too few maintenance studies have been conducted to make any firm assertions. However, with respect to long-term therapy the atypical antipsychotics do have clinically significant side-effects of which clinicians need to be aware.

CONCLUSION

Based on the evidence thus far it is perhaps premature to describe the atypical antipsychotics as mood stabilizers. Individual agents may eventually be able to claim this label, however, much further research is needed especially with respect to maintenance and relapse prevention.

Treatment of residual anxiety symptoms with adjunctive aripiprazole in depressed patients taking selective serotonin reuptake inhibitors

BACKGROUND

Depression and anxiety are common disorders and have substantially overlapping symptom complexes. Not surprisingly, treatment approaches are similar for both conditions with the selective serotonin reuptake inhibitors (SSRIs) as the initial therapy of choice. However, after first line treatments have been deployed, residual symptoms are often problematic. Augmentation strategies to address these difficulties are an area of active investigation. This study assessed aripiprazole as adjunctive therapy to SSRIs for patients with persistent anxiety symptoms complicating a depression or anxiety disorder.

METHODS

Ten patients who had been receiving SSRIs for at least 6 weeks, but still had clinically significant anxiety symptoms, were enrolled in an open label, flexibly-dosed study of adjunctive aripiprazole. Clinical status was assessed with the Hamilton Anxiety Rating Scale (HAM-A), Montgomery Asberg Rating Scale (MADRS), and Sheehan Disability Scale (SDS).

RESULTS

Eighty percent of the subjects had a greater than 50% reduction of symptoms on these outcome measures by week 2 of therapy, and continued with further decrements in symptoms throughout the course of the study.

CONCLUSIONS

The results of this trial provide preliminary evidence that aripiprazole may be an effective adjunctive treatment in individuals on SSRIs with residual symptoms of anxiety or depression. More rigorous double-blind studies are warranted to confirm and elucidate the potential role of aripiprazole in these conditions.