What is the mechanism for aripiprazole's effect on reducing olanzapine-associated obesity?

Effect of aripiprazole as an adjunct to atypical antipsychotics on weight and metabolic profile: a 12-week open-label trial

BACKGROUND

Atypical antipsychotics are widely prescribed, yet have been associated with weight gain and metabolic syndrome.

AIM

To study the effect of adjunct low-dose aripiprazole on weight and metabolic parameters of subjects on atypical antipsychotics (olanzapine, clozapine or risperidone).

METHODS

The study was carried out as an open-label trial with a fixed dose of 5 mg aripiprazole added to the patient's current antipsychotic for 12 weeks. The primary outcome measure was mean change in weight, while secondary outcome measures included change in waist circumference; fasting blood glucose; HbA1c; triglycerides; total, HDL and LDL cholesterol levels; functioning; and neurocognition.

RESULTS

For the overall study (n = 55), there was no significant effect of adjunct aripiprazole on the weight of the subjects. However, the clozapine group achieved significant weight loss (p = 0.002) and also had significant improvements in total cholesterol (p < 0.001), HDL (p = 0.016), LDL (p = 0.044) and triglyceride levels (p = 0.038). The olanzapine group had significant improvement in triglycerides (p = 0.001), and other metabolic parameters for this group showed improvement trends, but did not reach statistical significance. The risperidone group did not show any significant improvement in weight or metabolic parameters.

CONCLUSIONS

The study adds support to the adjunctive use of aripiprazole to clozapine for weight loss and improvement in metabolic profile, and for reduction in cardiometabolic risk for patients on olanzapine.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02949752.

Pathophysiological mechanisms of increased cardiometabolic risk in people with schizophrenia and other severe mental illnesses

Patients with schizophrenia have increased mortality and morbidity compared with the general population. These patients have a 20-year shorter lifespan than peers without schizophrenia, mainly due to premature cardiovascular disease, suicide, and cancer. Patients with severe mental illness are at increased risk for cardiovascular disease related to increased incidence of diabetes, hypertension, smoking, poor diet, obesity, dyslipidaemia, metabolic syndrome, low physical activity, and side-effects of antipsychotic drugs. Some second-generation antipsychotics (eg, clozapine, olanzapine, quetiapine, and risperidone) are associated with an increased risk of weight gain and obesity, impaired glucose tolerance and new-onset diabetes, hyperlipidaemia, and cardiovascular disease. The mechanisms by which schizophrenia and patients with severe mental illness are susceptible to cardiometabolic disorders are complex and include lifestyle risks and direct and indirect effects of antipsychotic drugs. An understanding of these risks might lead to effective interventions for prevention and treatment of cardiometabolic disorders in schizophrenia and severe mental illness.

Clinical management of comorbid diabetes and psychotic disorders

Individuals with psychotic disorders experience substantial health disparities with respect to diabetes, including increased risk of incident diabetes and of poor diabetes outcomes (eg, diabetes complications and mortality). Low-quality medical care for diabetes is a significant contributor to these poor health outcomes. A thoughtful approach to both diabetes pharmacotherapy and drug management for psychotic disorders is essential, irrespective of whether treatment is given by a psychiatrist, a primary care provider, or an endocrinologist. Exposure to drugs with high metabolic liability should be minimised, and both psychiatric providers and medical providers need to monitor patients to ensure that medical care for diabetes is adequate. Promising models of care management and team approaches to coordination and integration of care highlight the crucial need for communication and cooperation among medical and psychiatric providers to improve outcomes in these patients. Evidence-based programmes that promote weight loss or smoking cessation need to be more accessible for these patients, and should be available in all the settings where they access care.

Aripiprazole-associated hiccups: a case and closer look at the association between hiccups and antipsychotics

Aripiprazole's pharmacologic properties (including dopamine 2 and 5-hydroxytryptamine 1A [5HT1A] receptor partial agonism and 5HT2A receptors antagonism) may be associated with the onset of hiccups.

CASE DESCRIPTION

A 21-year-old, antipsychotic-naive patient with bipolar I disorder and remote brain trauma developed persistent hiccups following aripiprazole titration. Despite trials of metoclopramide and chlorpromazine, hiccups continued. Remission of hiccups occurred with discontinuation of aripiprazole.

DISCUSSION

The exact etiology of hiccups is unknown but likely involves dopamine and/or γ-butyric acid. Highlighting the uncertainty related to drug-induced hiccups is the fact that multiple antipsychotics have been reported to not only induce hiccups but also to alleviate them. As the development of persistent hiccups may result in extensive medical workup, clinicians should be aware of drug-associated causes including aripiprazole.

Adjunctive effects of aripiprazole on metabolic profiles: comparison of patients treated with olanzapine to patients treated with other atypical antipsychotic drugs

Metabolic abnormalities are serious adverse effects of atypical antipsychotic treatment. This study aims to determine the effects of adjunctive aripiprazole on metabolic profiles among patients receiving treatment with atypical antipsychotics, and to examine whether these effects are different from that of pre-existing atypical antipsychotics. In the 8-week open-label trial, aripiprazole was added to patients who were receiving treatment with atypical antipsychotics and had experienced weight gain or dyslipidemia. The dosage of pre-existing atypical antipsychotics was fixed, while the dosage of aripiprazole ranged from 5 to 20 mg/day during the study period. Metabolic profiles, including body weight, body mass index (BMI), plasma levels of fasting glucose, triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, and adiponectin, were measured at baseline and week 8. As a result, 43 subjects (16 males and 27 females, mean age: 37.8±10.8 years) completed the study. The pre-existing antipsychotics were olanzapine (n=12), risperidone (n=19), quetiapine (n=6) and amisulpiride (n=6). The mean dosage of adjunctive aripiprazole was 9.9±3.2 mg/day. After the aripiprazole-augmented regimen for 8 weeks, patients treated with olanzapine had significant decreases in body weight, BMI and triglyceride levels, and had significant increases in adiponectin levels. For patients treated with other atypical antipsychotics, none of the metabolic parameters significantly changed after administering aripiprazole. In conclusion, aripiprazole-augmented treatment might be beneficial for the metabolic regulation of patients being treated with a stable dose of olanzapine, but not for those treated with other atypical antipsychotics. A long-term, randomized, double-blind controlled design is suggested to confirm these findings.

Atypical antipsychotic-induced weight gain: insights into mechanisms of action

Prescriptions for second-generation antipsychotics (SGAs) have surpassed those for first-generation agents in the treatment of schizophrenia and bipolar disorder. While SGAs have the benefit of a much reduced risk of causing movement disorders, they have been associated with weight gain and metabolic effects. These adverse reactions are not uncommon, and threaten to have a significant impact on the patient's health over the long-term treatment that the patient requires. Currently, the aetiology of these effects is not known. This article reviews the data exploring the weight gain phenomenon. The literature was reviewed from searches of PubMed and the references of major articles in the field. The SGAs present a heterogeneous risk for weight gain. In addition, different individuals receiving the same drug can exhibit substantially different weight changes. This pattern suggests that a group of factors are associated with the weight gain phenomenon rather than a single mechanism. Coupled with the genetic profile that the patient brings to the treatment, the risk for SGA-induced weight gain will be different for different drugs and different individuals. Targets for exploration of the weight gain phenomenon include receptor interactions involving serotonin, histamine, dopamine, adrenergic, cannabinoid and muscarinic receptors. The association of SGA-induced weight gain and the role of orexigenic and anorexigenic peptides are reviewed. Also, a brief discussion of genetic factors associated with SGA-induced weight gain is presented, including that of the serotonin 5-HT(2C) receptor gene (HTR2C) and the cannabinoid 1 receptor gene (CNR1). The most promising data associated with SGA-induced weight gain include investigations of the histamine H(1), 5-HT(2A), 5-HT(2C), muscarinic M(3) and adrenergic receptors. In addition, work in the genetic area promises to result in a better understanding of the variation in risk associated with different individuals.