Aripiprazole versus typical antipsychotic drugs for schizophrenia

Consequences of Antipsychotic Medications on Mental Health

Individuals suffering from mental illnesses, unfortunately, have a shorter lifespan. The increase in mortality rates is primarily due to physical illness, unhealthy lifestyle, and associated comorbidities. Antipsychotic medications, previously known as tranquilizers, antipsychotics, or neuroleptics, can alleviate or attenuate symptoms related to psychosis, delusion, and/or hallucinations and are used in the treatment of psychosis, schizophrenia, bipolar disorder, depression, or Alzheimer's disease. Within hours to days, these medications cause calm and reduce confusion in individuals with psychosis however may take longer for full effect. Importantly, these drugs are not curing, but only treat the disease symptoms. The treatment is adjusted to reduce any psychotic symptoms while keeping the adverse effects to a minimum level. Antipsychotics may lead to increased risk of diseases, including but not limited to, diabetes, obesity, metabolic disorders, cardiovascular, renal, or respiratory disorders. Improved dosages, polypharmacy, and age-specific treatment play an important role in limiting the comorbidities as well as the side effects. Further research and clinical attention are required to understand the functioning of these medications. The review focuses on the use of antipsychotic medications in different diseases and their effect on mental health.

[Modern possibilities of anti-relapse therapy of schizophrenia (experience with the use of aripiprazole)]

The review is devoted to the actual problem of anti-relapse therapy for schizophrenia. The features of the use, efficiency, tolerability and safety of typical and atypical antipsychotics are discussed. The possibilities of using atypical antipsychotics of the third generation - partial dopamine receptor agonists - on the aripiprazole model are considered. According to numerous studies, aripiprazole, due to its unique pharmacological profile and combination of clinical factors, is the drug of first choice for anti-relapse supportive therapy of schizophrenia.

Safety and Efficacy of High-Dose Vitamin B6 as an Adjunctive Treatment for Antipsychotic-Induced Hyperprolactinemia in Male Patients With Treatment-Resistant Schizophrenia

This study aimed to investigate the safety and efficacy of high-dose vitamin B6 (vB6) as an adjunct treatment for antipsychotic-induced hyperprolactinemia (AIHP) in male patients with treatment-resistant schizophrenia (TRS). In this randomized double-blinded controlled study, patients were randomized (1:1) into a control group given aripiprazole (ARI; 10 mg/day; n = 100) or an intervention group given vB6 (300 mg/12 h for 16 weeks; n = 100). Prolactin levels, psychotic symptoms [Positive and Negative Syndrome Scale (PANSS)], cognitive function [MATRICS Consensus Cognitive Battery (MCCB)], liver function, kidney function, growth hormone level, micronutrient levels, blood lipids, and adverse secondary effects (ASEs)[Treatment Emergent Symptom Scale (TESS) and Barnes-Akathisia scale] were monitored. After a 16-week treatment period, the vB6 group showed a 68.1% reduction in serum prolactin levels (from 95.52 ± 6.30 μg/L to 30.43 ± 18.65 μg/L) while the ARI group showed only a 37.4% reduction (from 89.07 ± 3.59 μg/L to 55.78 ± 7.39 μg/L). During weeks 1-4, both treatments reduced prolactin similarly. Subsequently, the ARI effect plateaued, while the vB6 effect remained robust. The vB6 group showed better alleviation of psychotic symptoms and cognitive impairment. No serious ASEs were observed; ASEs were more frequent in the ARI group. AIHP reduction efficacy of vB6 was associated with baseline prolactin and triglyceride levels, total vB6 dosage, and education level. In conclusion, compared with the ARI group, TRS patients given vB6 showed better attenuation of AIHP, lower ASE scores, and greater improvements in clinical symptoms and cognitive impairments. These results support further consideration of vB6 as a putative treatment for AIHP. Trial Registration: ChiCTR1800014755.

Abnormally low prolactin levels in schizophrenia patients after switching to aripiprazole in a randomized trial: a biomarker for rebound in psychotic symptoms?

BACKGROUND

Switching to aripiprazole from other antipsychotics can avoid antipsychotic-induced hyperprolactinemia but may result in an abnormally low prolactin level. This study aimed to assess whether the aripiprazole-induced abnormally low prolactin level was a biomarker for subsequent rebound of positive symptoms in schizophrenia patients.

METHODS

Participants were 63 patients in an 8-week trial of switching to aripiprazole, in which preswitching antipsychotics were maintained for the first 2 weeks and aripiprazole was fixed at 15 mg orally throughout the trial. A prolactin level of < 3.7 ng/ml was defined as abnormally low, and an increase of two or more points in the positive subscore of the Positive and Negative Syndrome Scale at two adjacent ratings was defined as a psychotic rebound.

RESULTS

Among 63 patients, 25 (39.7%) had an abnormally low prolactin level and 21 (33.3%) had a psychotic rebound after switching to aripiprazole. In patients with abnormally low prolactin levels, 48.0% of them had a rebound in psychotic symptoms, whereas in those without abnormally low prolactin levels 23.7% did so. Multivariable logistic regression analysis with adjustment for sex, early age at onset, and preswitching medications revealed that abnormally low prolactin levels were associated with psychotic rebound (adjusted odds ratio = 3.55, 95% confidence interval = 1.02, 12.5). Furthermore, there was concurrency between the trend of the cumulative proportion of patients having an abnormally low prolactin level and that of the cumulative proportion of patients having a rebound in psychotic symptoms.

CONCLUSIONS

An abnormally low prolactin level after switching to aripiprazole in schizophrenia patients was a potential warning sign of a psychotic rebound. Hence, monitoring of prolactin levels after switching to aripiprazole may help avoid such rebound in schizophrenia.

TRIAL REGISTRATION

NCT00545467 ; Date of registration: 17/10/2007.

Optimization of Processing Parameters of Nanoemulsion Containing Aripiprazole Using Response Surface Methodology

BACKGROUND

Aripiprazole, which is a quinolinone derivative, has been widely used to treat schizophrenia, major depressive disorder, and bipolar disorder.

PURPOSE

A Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) was used purposely to optimize process parameters conditions for formulating nanoemulsion containing aripiprazole using high emulsification methods.

METHODS

This design is used to investigate the influences of four independent variables (overhead stirring time (A), shear rate (B), shear time (C), and the cycle of high-pressure homogenizer (D)) on the response variable namely, a droplet size (Y) of nanoemulsion containing aripiprazole.

RESULTS

The optimum conditions suggested by the predicted model were: 120 min of overhead stirring time, 15 min of high shear homogenizer time, 4400 rpm of high shear homogenizer rate and 11 cycles of high-pressure homogenizer, giving a desirable droplet size of nanoemulsion containing aripiprazole of 64.52 nm for experimental value and 62.59 nm for predicted value. The analysis of variance (ANOVA) showed the quadratic polynomial fitted the experimental values with F-value (9.53), a low p-value (0.0003) and a non-significant lack of-fit. It proved that the models were adequate to predict the relevance response. The optimized formulation with a viscosity value of 3.72 mPa.s and pH value of 7.4 showed good osmolality value (297 mOsm/kg) and remained stable for three months in three different temperatures (4°C, 25°C, and 45°C).

CONCLUSION

This proven that response surface methodology is an efficient tool to produce desirable droplet size of nanoemulsion containing aripiprazole for parenteral delivery application.

Adjunctive Peony-Glycyrrhiza decoction for antipsychotic-induced hyperprolactinaemia: a meta-analysis of randomised controlled trials

BACKGROUND

Hyperprolactinaemia is a common adverse effect of antipsychotics (APs). The results of Peony-Glycyrrhiza decoction (PGD) as a potentially useful adjunctive treatment for hyperprolactinaemia are inconsistent.

AIM

This meta-analysis of randomised controlled trials (RCTs) examined the efficacy and safety of adjunctive PGD therapy for AP-induced hyperprolactinaemia.

METHODS

English (PubMed, Embase, Cochrane Library, PsycINFO) and Chinese (Chinese National Knowledge Infrastructure, Wanfang Data) databases were systematically searched up to 10 June 2018. The inclusion criteria were based on PICOS-Participants: adult patients with schizophrenia; Intervention: PGD plus APs; Comparison: APs plus placebo or AP monotherapy; Outcomes: efficacy and safety; Study design: RCTs. The weighted mean difference (WMD) and risk ratio (RR) along with their 95% CIs were calculated using Review Manager (RevMan) V.5.3 software.

RESULTS

Five RCTs (n=450) were included and analysed. Two RCTs (n=140) were double-blind and four RCTs (n=409) reported 'random' assignment with specific description. The PGD group showed a significantly lower serum prolactin level at endpoint than the control group (n=380, WMD: -32.69  ng/mL (95%  CI -41.66 to 23.72), p<0.00001, I 2 =97%). Similarly, the superiority of PGD over the control groups was also found in the improvement of hyperprolactinaemia-related symptoms. No difference was found in the improvement of psychiatric symptoms assessed by the Positive and Negative Syndrome Scale (n=403, WMD: -0.62 (95% CI -2.38 to 1.15), p=0.49, I 2 =0%). There were similar rates of all-cause discontinuation (n=330, RR 0.93 (95% CI 0.63 to 1.37), p=0.71, I 2 =0%) and adverse drug reactions between the two groups. According to the Grading of Recommendations Assessment, Development and Evaluation approach, the level of evidence of primary and secondary outcomes ranged from 'very low' (14.3%), 'low' (42.8%), 'moderate' (14.3%), to 'high' (28.6%).

CONCLUSIONS

Current evidence supports the adjunctive use of PGD to suppress elevated prolactin and improve prolactin-induced symptoms without significant adverse events in adult patients with AP-induced hyperprolactinaemia. High-quality RCTs with longer duration are needed to confirm these findings.

TRIAL REGISTRATION NUMBER

42016037017.

Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews

PURPOSE

To conduct an overview to summarize the efficacy and safety of aripiprazole for the treatment of schizophrenia.

METHODS

A literature search was performed in PubMed, the Cochrane Library, LILACS, and the Centre for Reviews and Dissemination, for articles published until March 31, 2017. We included systematic reviews with meta-analyses of randomized controlled trials assessing the efficacy, and/or the safety of aripiprazole, for patients with schizophrenia. Two authors independently performed the study selection, data extraction, and quality assessment. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach and the Risk of Bias in Systematic Review (ROBIS) tool were used to appraise the quality of evidence and the risk of bias in the reviews, respectively.

RESULTS

Fourteen studies fulfilled the inclusion criteria. Aripiprazole showed efficacy similar to that of both typical and atypical antipsychotic drugs (except olanzapine and amisulpride). Aripiprazole caused significantly lower weight gain and alterations in glucose and cholesterol levels, as compared to clozapine, risperidone, and olanzapine. In addition, aripiprazole caused significantly fewer general extrapyramidal side effects, less use of antiparkinsonian drugs, and akathisia, compared with typical antipsychotic drugs and risperidone. The overall quality of evidence in the reviews ranged from "very low" to "moderate," principally because of the risk of bias of original trials, inconsistency, and imprecision in the outcomes. According to the ROBIS tool, there are four reviews with "high" risk of bias and five with "unclear" risk of bias.

CONCLUSIONS

Aripiprazole exhibited efficacy similar to that of other antipsychotic drugs and a better safety profile than that of typical (i.e., less some extrapyramidal side effects) and atypical (i.e., less metabolic changes) antipsychotic drugs.

Movement Disorders Associated With Antipsychotic Medication in People With Schizophrenia: An Overview of Cochrane Reviews and Meta-Analysis

Movement disorders associated with antipsychotic medications are relatively common, stigmatising, and potentially disabling. Their prevalence in people with psychosis who are prescribed second-generation antipsychotics (SGAs) is uncertain, as is their level of recognition by clinicinas. We conducted meta-analyses of randomised controlled trials included in the Cochrane Database of Systematic Reviews on schizophrenia and schizophrenia-like psychoses to estimate the prevalence of new-onset dystonia, akathisia, parkinsonism, and tremor with SGAs (amisulpride, asenapine, aripiprazole, clozapine, olanzapine, paliperidone, quetiapine, risperidone, L-sulpiride, and ziprasidone) approved in Canada and the UK, comparing them with haloperidol and chlorpromazine. We used a random effects model because of the heterogeneity between-studies in drug dosage and method of ascertainment of movement disorders. Our systematic search yielded 37 Cochrane systematic reviews (28 for SGAs), which generated 316 informative randomised controlled trials (243 for SGAs). With respect to SGAs, prevalence estimates ranged from 1.4% (quetiapine) to 15.3% (L-sulpiride) for dystonia, 3.3% (paliperidone) to 16.4% (L-sulpiride) for akathisia, 2.4% (asenapine) to 29.3% (L-sulpiride) for parkinsonism, and 0.2% (clozapine) to 28.2% (L-sulpiride) for tremor. Prevalence estimates were not influenced by treatment duration, the use of a flexible or fixed dosing scheme, or whether studies used validated instruments for the screening/rating of movement disorders. Overall, we found high overlap on the prevalence of new-onset movement disorders across different SGAs precribed for established psychoses. Variations in prevalence figures across antipsychotic medications were observed for the different movement disorders. Differences in pharmacological properties, such as for the dopamine D2 R association rate and serotonin 5-HT2A antagonism, could contribute to this variation.

Risperidone versus placebo for schizophrenia

BACKGROUND

Risperidone is the first new-generation antipsychotic drug made available in the market in its generic form.

OBJECTIVES

To determine the clinical effects, safety and cost-effectiveness of risperidone compared with placebo for treating schizophrenia.

SEARCH METHODS

On 19th October 2015, we searched the Cochrane Schizophrenia Group Trials Register, which is based on regular searches of CINAHL, BIOSIS, AMED, EMBASE, PubMed, MEDLINE, PsycINFO, and registries of clinical trials. We checked the references of all included studies and contacted industry and authors of included studies for relevant studies and data.

SELECTION CRITERIA

Randomised clinical trials (RCTs) comparing oral risperidone with placebo treatments for people with schizophrenia and/or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies, assessed the risk of bias of included studies and extracted data. For dichotomous data, we calculated the risk ratio (RR), and the 95% confidence interval (CI) on an intention-to-treat basis. For continuous data, we calculated mean differences (MD) and the 95% CI. We created a 'Summary of findings table' using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

MAIN RESULTS

The review includes 15 studies (N = 2428). Risk of selection bias is unclear in most of the studies, especially concerning allocation concealment. Other areas of risk such as missing data and selective reporting also caused some concern, although not affected on the direction of effect of our primary outcome, as demonstrated by sensitivity analysis. Many of the included trials have industry sponsorship of involvement. Nonetheless, generally people in the risperidone group are more likely to achieve a significant clinical improvement in mental state (6 RCTs, N = 864, RR 0.64, CI 0.52 to 0.78, very low-quality evidence). The effect withstood, even when three studies with >50% attrition rate were removed from the analysis (3 RCTs, N = 589, RR 0.77, CI 0.67 to 0.88). Participants receiving placebo were less likely to have a clinically significant improvement on Clinical Global Impression scale (CGI) than those receiving risperidone (4 RCTs, N = 594, RR 0.69, CI 0.57 to 0.83, very low-quality evidence). Overall, the risperidone group was 31% less likely to leave early compared to placebo group (12 RCTs, N = 2261, RR 0.69, 95% CI 0.62 to 0.78, low-quality evidence), but Incidence of significant extrapyramidal side effect was more likely to occur in the risperidone group (7 RCTs, N = 1511, RR 1.56, 95% CI 1.13 to 2.15, very low-quality evidence).When risperidone and placebo were augmented with clozapine, there is no significant differences between groups for clinical response as defined by a less than 20% reduction in PANSS/BPRS scores (2 RCTs, N = 98, RR 1.15, 95% CI 0.93 to 1.42, low-quality evidence) and attrition (leaving the study early for any reason) (3 RCTs, N = 167, RR 1.13, 95% CI 0.53 to 2.42, low quality evidence). One study measured clinically significant responses using the CGI, no effect was evident (1 RCT, N = 68, RR 1.12 95% CI 0.87 to 1.44, low quality evidence). No data were available for extrapyramidal adverse effects.

AUTHORS' CONCLUSIONS

Based on low quality evidence, risperidone appears to be benefitial in improving mental state compared with placebo, but it also causes more adverse events. Eight out of the 15 included trials were funded by pharmaceutical companies. The currently available evidence isvery low to low quality.

Enhancement of encapsulation efficiency of nanoemulsion-containing aripiprazole for the treatment of schizophrenia using mixture experimental design

Aripiprazole is considered as a third-generation antipsychotic drug with excellent therapeutic efficacy in controlling schizophrenia symptoms and was the first atypical anti-psychotic agent to be approved by the US Food and Drug Administration. Formulation of nanoemulsion-containing aripiprazole was carried out using high shear and high pressure homogenizers. Mixture experimental design was selected to optimize the composition of nanoemulsion. A very small droplet size of emulsion can provide an effective encapsulation for delivery system in the body. The effects of palm kernel oil ester (3–6 wt%), lecithin (2–3 wt%), Tween 80 (0.5–1 wt%), glycerol (1.5–3 wt%), and water (87–93 wt%) on the droplet size of aripiprazole nanoemulsions were investigated. The mathematical model showed that the optimum formulation for preparation of aripiprazole nanoemulsion having the desirable criteria was 3.00% of palm kernel oil ester, 2.00% of lecithin, 1.00% of Tween 80, 2.25% of glycerol, and 91.75% of water. Under optimum formulation, the corresponding predicted response value for droplet size was 64.24 nm, which showed an excellent agreement with the actual value (62.23 nm) with residual standard error <3.2%.

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND

In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first-line drug treatments for people with schizophrenia. In this review, we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics.

OBJECTIVES

To review the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group Trials Register (November 2012), inspected references of all identified studies for further trials and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information.

SELECTION CRITERIA

We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study and used GRADE approach to rate quality of evidence.

MAIN RESULTS

We now have included 174 trials involving 17,244 participants. Aripiprazole was compared with clozapine, quetiapine, risperidone, ziprasidone and olanzapine. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with clozapine, there were no significant differences for global state (no clinically significant response, n = 2132, 29 RCTs, low quality evidence); mental state (BPRS, n = 426, 5 RCTs, very low quality evidence); or leaving the study early for any reason (n = 240, 3 RCTs, very low quality evidence). Quality of life score using the WHO-QOL-100 scale demonstrated significant difference, favouring aripiprazole (n = 132, 2 RCTs, RR 2.59 CI 1.43 to 3.74, very low quality evidence). General extrapyramidal symptoms (EPS) were no different between groups (n = 520, 8 RCTs,very low quality evidence). No study reported general functioning or service use.When compared with quetiapine, there were no significant differences for global state (n = 991, 12 RCTs, low quality evidence); mental state (PANSS positive symptoms, n = 583, 7 RCTs, very low quality evidence); leaving the study early for any reason (n = 168, 2 RCTs, very low quality evidence), or general EPS symptoms (n = 348, 4 RCTs, very low quality evidence). Results were significantly in favour of aripiprazole for quality of life (WHO-QOL-100 total score, n = 100, 1 RCT, MD 2.60 CI 1.31 to 3.89, very low quality evidence). No study reported general functioning or service use.When compared with risperidone, there were no significant differences for global state (n = 6381, 80 RCTs, low quality evidence); or leaving the study early for any reason (n = 1239, 12 RCTs, very low quality evidence). Data were significantly in favour of aripiprazole for improvement in mental state using the BPRS (n = 570, 5 RCTs, MD 1.33 CI 2.24 to 0.42, very low quality evidence); with higher adverse effects seen in participants receiving risperidone of general EPS symptoms (n = 2605, 31 RCTs, RR 0.39 CI 0.31 to 0.50, low quality evidence). No study reported general functioning, quality of life or service use.When compared with ziprasidone, there were no significant differences for global state (n = 442, 6 RCTs, very low quality evidence); mental state using the BPRS (n = 247, 1 RCT, very low quality evidence); or leaving the study early for any reason (n = 316, 2 RCTs, very low quality evidence). Weight gain was significantly greater in people receiving aripiprazole (n = 232, 3 RCTs, RR 4.01 CI 1.10 to 14.60, very low quality evidence). No study reported general functioning, quality of life or service use.When compared with olanzapine, there were no significant differences for global state (n = 1739, 11 RCTs, very low quality evidence); mental state using PANSS (n = 1500, 11 RCTs, very low quality evidence); or quality of life using the GQOLI-74 scale (n = 68, 1 RCT, very low quality of evidence). Significantly more people receiving aripiprazole left the study early due to any reason (n = 2331, 9 RCTs, RR 1.15 CI 1.05 to 1.25, low quality evidence) and significantly more people receiving olanzapine gained weight (n = 1538, 9 RCTs, RR 0.25 CI 0.15 to 0.43, very low quality evidence). None of the included studies provided outcome data for the comparisons of 'service use' or 'general functioning'.

AUTHORS' CONCLUSIONS

Information on all comparisons is of limited quality, is incomplete and problematic to apply clinically. The quality of the evidence is all low or very low. Aripiprazole is an antipsychotic drug with an important adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerge from ongoing larger, independent pragmatic trials.

Aripiprazole induced severe and extensive skin reaction: A case report

Adverse cutaneous reactions are one of the most frequent types of adverse drug reactions, and have been reported with a wide range of psychotropics including typical and atypical antipsychotics. However the majority of adverse cutaneous reactions are relatively minor, and severe reactions are relatively rare. Aripiprazole is a third-generation atypical antipsychotic that has been available in the UK for over seven years. Here the author reports the first reported case of a lichenoid drug reaction to aripiprazole, a severe and potentially life-threatening adverse cutaneous reaction that required medical and surgical intervention.

Striatal and extrastriatal dopamine D₂ receptor occupancy by the partial agonist antipsychotic drug aripiprazole in the human brain: a positron emission tomography study with [¹¹C]raclopride and [¹¹C]FLB457

RATIONALE

Second-generation antipsychotics demonstrate clinical efficacy with fewer extrapyramidal side effects compared with first-generation antipsychotics. One of the proposed explanations is the hypothesis of preferential extrastriatal dopamine D₂ receptor occupancy (limbic selectivity) by antipsychotics. In the present study, we focused on aripiprazole, which has a unique pharmacological profile with partial agonism at dopamine D₂ receptors and the minimal risk of extrapyramidal side effects. Previous positron emission tomography (PET) studies using high-affinity radioligands for dopamine D₂ receptors have reported inconsistent results regarding regional differences of dopamine D₂ receptor occupancy by aripiprazole.

OBJECTIVE

To test the hypothesis of preferential binding to extrastriatal dopamine D₂ receptors by aripiprazole, we investigated its regional dopamine D₂ receptor occupancies in healthy young subjects.

MATERIALS AND METHODS

Using PET and two radioligands with different affinities for dopamine D₂ receptors, [¹¹C]raclopride and [¹¹C]FLB457, striatal and extrastriatal dopamine D₂ receptor bindings at baseline and after oral administration of 6 mg aripiprazole were measured in 11 male healthy subjects.

RESULTS

Our data showed that dopamine D₂ receptor occupancies in the striatum measured with [¹¹C]raclopride were 70.1% and 74.1%, with the corresponding values for the extrastriatal regions measured with [¹¹C]FLB457 ranging from 46.6% to 58.4%.

CONCLUSIONS

In the present study, preferential extrastriatal dopamine D₂ receptor occupancy by aripiprazole was not observed. Our data suggest partial agonism at dopamine D₂ receptors is the most likely explanation for the minimal risk of extrapyramidal side effects in the treatment by aripiprazole.

Role of aripiprazole in treatment-resistant schizophrenia

About one third of patients with schizophrenia respond unsatisfactorily to antipsychotic treatment and are termed "treatment-resistant". Clozapine is still the gold standard in these cases. However, 40%-70% of patients do not improve sufficiently on clozapine either. In the search for more efficacious strategies for treatment-resistant schizophrenia, drugs with different pharmacological profiles seem to raise new hopes, but are they valid? The aim of this review was to evaluate the evidence for aripiprazole as a potential strategy in monotherapy or combination therapy for patients with treatment-resistant schizophrenia. The evidence for aripiprazole monotherapy and for the combination of aripiprazole with psychotropics other than clozapine is scant, and no recommendation can be made on the basis of the currently available data. More effort has been made in describing combinations of aripiprazole and clozapine. Most of the open-label and case studies as well as case reports have shown positive effects of this combination on overall psychopathology and to some extent on negative symptoms. Several reports describe the possibility of dose reduction for clozapine in combination with aripiprazole, a strategy that might help so-called "treatment-intolerant" patients. The findings of four randomized controlled trials with respect to changes in psychopathology seem less conclusive. The most commonly found beneficial effects are better metabolic outcomes and indicators of the possibility of reducing the clozapine dose. However, other side effects, such as akathisia, are repeatedly reported. Further, none of the studies report longer-term outcomes. In the absence of alternatives, polypharmacy is a common strategy in clinical practice. Combining aripiprazole with clozapine in clozapine-resistant or clozapine-intolerant patients seems to be worthy of further investigation from the pharmacological and clinical points of view.

Predictors of early worsening after switch to aripiprazole: a randomized, controlled, open-label study

BACKGROUND

Despite the increasing evidence relating to strategies for switching between different antipsychotics, little evidence is available about predictors of improvement or worsening while switching. In a previous study, we compared different options for switching to aripiprazole and found that patients with schizophrenia switched to aripiprazole with immediate discontinuation of the previous antipsychotic showed an increase in symptom severity after 1 week.

OBJECTIVE

To identify predictors of worsening in the first 4 weeks after the switch to aripiprazole in partial non-responders to previous treatments.

METHODS

This was a 12-week randomized, controlled, open-label study that was carried out in the Department of Psychiatry of the Catholic University of Korea, Seoul, Korea. The study included 77 patients with schizophrenia whose symptoms were not optimally controlled and/or who did not tolerate their current antipsychotic medications well. Patients were randomly assigned to one of three different strategies for switching to aripiprazole 10 mg, i.e.: (i) simultaneous discontinuation of the current antipsychotic; (ii) tapering off the current antipsychotic over 4 weeks with half the dose after the first 2 weeks; or (iii) tapering off the current antipsychotic over 4 weeks after maintenance of the current dose for 2 weeks. The main outcome measure was the difference in Brief Psychiatric Rating Scale (BPRS) scores from baseline to weeks 1, 2 and 4.

RESULTS

Baseline severity of disease, as measured by the Clinical Global Impression-Severity Scale, BPRS and Schedule for the Assessment of Negative Symptoms, significantly predicted worsening at weeks 1, 2 and 4. Specifically, lesser disease severity at baseline significantly predicted worsening after switching to aripiprazole.

CONCLUSION

Patients with relatively mild illness severity might be more susceptible to early worsening of symptoms when switched to aripiprazole. However, the limitations of the present study, including a small sample size, absence of a control group designed to control for nonspecific factors such as regression to the mean, and implementation of a switching strategy that included only aripiprazole, mean the present findings should be considered with caution and further research is needed.