The effect of betahistine, a histamine H1 receptor agonist/H3 antagonist, on olanzapine-induced weight gain in first-episode schizophrenia patients

Effects of Adjunctive Betahistine Therapy on Lipid Metabolism in Patients with Chronic Schizophrenia: A Randomized Double-Blind Placebo-Controlled Study

OBJECTIVE

This study aims to explore the ability of betahistine to inhibit weight gain and abnormal lipid metabolism in patients with chronic schizophrenia.

METHODS

A comparison study of betahistine or placebo therapy was conducted for 4 weeks in 94 patients with chronic schizophrenia, who were randomly divided into two groups. Clinical information and lipid metabolic parameters were collected. Positive and Negative Syndrome Scale (PANSS) was used to assess psychiatric symptoms. Treatment Emergent Symptom Scale (TESS) was used to evaluate treatment-related adverse reactions. The differences in lipid metabolic parameters before and after treatment between the two groups were compared.

RESULTS

Repeated measures analysis of variance (ANOVA) revealed that after 4 weeks of betahistine/placebo treatment, the interaction effect of time and group was statistically significant on low-density lipoprotein cholesterol (F = 6.453, p = 0.013) and waist-to-hip ratio (F = 4.473, p = 0.037), but did not reveal any significant interaction effect of time and group on weight, body mass index or other lipid metabolic parameters, as well as the time main effect and group main effect (all p > 0.05). Betahistine had no significant impact on PANSS, and no side effects related to betahistine were detected.

CONCLUSION

Betahistine may delay metabolic abnormalities in patients with chronic schizophrenia. It does not affect the efficacy of the original antipsychotics. Thus, it provides new ideas for the treatment of metabolic syndrome in patients with chronic schizophrenia.

Integrated Network Pharmacology Approach for Drug Combination Discovery: A Multi-Cancer Case Study

Despite remarkable efforts of computational and predictive pharmacology to improve therapeutic strategies for complex diseases, only in a few cases have the predictions been eventually employed in the clinics. One of the reasons behind this drawback is that current predictive approaches are based only on the integration of molecular perturbation of a certain disease with drug sensitivity signatures, neglecting intrinsic properties of the drugs. Here we integrate mechanistic and chemocentric approaches to drug repositioning by developing an innovative network pharmacology strategy. We developed a multilayer network-based computational framework integrating perturbational signatures of the disease as well as intrinsic characteristics of the drugs, such as their mechanism of action and chemical structure. We present five case studies carried out on public data from The Cancer Genome Atlas, including invasive breast cancer, colon adenocarcinoma, lung squamous cell carcinoma, hepatocellular carcinoma and prostate adenocarcinoma. Our results highlight paclitaxel as a suitable drug for combination therapy for many of the considered cancer types. In addition, several non-cancer-related genes representing unusual drug targets were identified as potential candidates for pharmacological treatment of cancer.

Targeting Histamine and Histamine Receptors for the Precise Regulation of Feeding

Histamine has long been accepted as an anorexigenic agent. However, lines of evidence have suggested that the roles of histamine in feeding behaviors are much more complex than previously thought, being involved in satiety, satiation, feeding motivation, feeding circadian rhythm, and taste perception and memory. The functional diversity of histamine makes it a viable target for clinical management of obesity and other feeding-related disorders. Here, we update the current knowledge about the functions of histamine in feeding and summarize the underlying molecular and neural circuit mechanisms. Finally, we review the main clinical studies about the impacts of histamine-related compounds on weight control and discuss insights into future research on the roles of histamine in feeding. Despite the recent progress in histamine research, the histaminergic feeding circuits are poorly understood, and it is also worth verifying the functions of histamine receptors in a more spatiotemporally specific manner.

Olanzapine-Induced Activation of Hypothalamic Astrocytes and Toll-Like Receptor-4 Signaling via Endoplasmic Reticulum Stress Were Related to Olanzapine-Induced Weight Gain

The antipsychotic drug olanzapine is associated with serious obesity side effects. Hypothalamic astrocytes and associated toll-like receptor-4 (TLR4) signaling play an essential role in obesity pathogenesis. This study investigated the effect of olanzapine on astrocytes and TLR4 signaling both in vitro and in the rat hypothalamus and their potential role in olanzapine-induced weight gain. We found that olanzapine treatment for 24 h dose-dependently increased cell viability, increased the protein expression of astrocyte markers including glial fibrillary acidic protein (GFAP) and S100 calcium binding protein B (S100B), and activated TLR4 signaling in vitro. In rats, 8- and 36-day olanzapine treatment caused weight gain accompanied by increased GFAP and S100B protein expression and activated TLR4 signaling in the hypothalamus. These effects still existed in pair-fed rats, suggesting that these effects were not secondary effects of olanzapine-induced hyperphagia. Moreover, treatment with an endoplasmic reticulum (ER) stress inhibitor, 4-phenylbutyrate, inhibited olanzapine-induced weight gain and ameliorated olanzapine-induced changes in hypothalamic GFAP, S100B, and TLR4 signaling. The expression of GFAP, S100B, and TLR4 correlated with food intake and weight gain. These findings suggested that olanzapine-induced increase in hypothalamic astrocytes and activation of TLR4 signaling were related to ER stress, and these effects may be related to olanzapine-induced obesity.

Olanzapine increases AMPK-NPY orexigenic signaling by disrupting H1R-GHSR1a interaction in the hypothalamic neurons of mice

Second generation antipsychotics, particularly olanzapine, induce severe obesity, which is associated with their antagonistic effect on the histamine H1 receptor (H1R). We have previously demonstrated that oral administration of olanzapine increases the concentration of neuropeptide Y (NPY) in the hypothalamus of rats, accompanied by hyperphagia and weight gain. However, it is unclear if the increased NPY after olanzapine administration is due to its direct effect on hypothalamic neurons and its H1R antagonistic property. In the present study, we showed that with an inverted U-shape dose-response curve, olanzapine increased NPY expression in the NPY-GFP hypothalamic neurons; however, this was not the case in the hypothalamic neurons of H1R knockout mice. Olanzapine inhibited the interaction of H1R and GHSR1a (ghrelin receptor) in the primary mouse hypothalamic neurons and NPY-GFP neurons examined by confocal fluorescence resonance energy transfer (FRET) technology. Furthermore, an H1R agonist, FMPH inhibited olanzapine activation of GHSR1a downstream signaling pAMPK and transcription factors of NPY (pFOXO1 and pCREB) in the hypothalamic NPY-GFP cell. However, an olanzapine analogue (E-Olan) with lower affinity to H1R presented negligible enhancement of pCREB within the nucleus of NPY neurons. These findings suggest that the H1R antagonist property of olanzapine inhibits the interaction of H1R and GHSR1a, activates GHSR1a downstream signaling pAMPK-FOXO1/pCREB and increases hypothalamic NPY: this could be one of the important molecular mechanisms of H1R antagonism of olanzapine-induced obesity in antipsychotic management of psychiatric disorders.

Olanzapine-induced endoplasmic reticulum stress and inflammation in the hypothalamus were inhibited by an ER stress inhibitor 4-phenylbutyrate

Antipsychotics are the most important treatment for schizophrenia. However, antipsychotics, particularly olanzapine and clozapine, are associated with severe weight gain/obesity side-effects. Although numerous studies have been carried out to identify the exact mechanisms of antipsychotic-induced weight gain, it is still important to consider other pathways. Endoplasmic reticulum (ER) stress signaling and its associated inflammation pathway is one of the most important pathways involved in regulation of energy balance. In the present study, we examined the role of hypothalamic protein kinase R like endoplasmic reticulum kinase- eukaryotic initiation factor 2α (PERK-eIF2α) signaling and the inflammatory IkappaB kinase β- nuclear factor kappa B (IKKβ-NFκB) signaling pathway in olanzapine-induced weight gain in female rats. In this study, we found that olanzapine significantly activated PERK-eIF2α and IKKβ-NFκB signaling in SH-SY5Y cells in a dose-dependent manner. Olanzapine treatment for 8 days in rats was associated with activated PERK-eIF2α signaling and IKKβ-NFκB signaling in the hypothalamus, accompanied by increased food intake and weight gain. Co-treatment with an ER stress inhibitor, 4-phenylbutyrate (4-PBA), decreased olanzapine-induced food intake and weight gain in a dose- and time-dependent manner. Moreover, 4-PBA dose-dependently inhibited olanzapine-induced activated PERK-eIF2α and IKKβ-NFκB signaling in the hypothalamus. These results suggested that hypothalamic ER stress may play an important role in antipsychotic-induced weight gain.

Antipsychotics-induced metabolic alterations: Recounting the mechanistic insights, therapeutic targets and pharmacological alternatives

Atypical antipsychotics (AAPs) are the drug of choice in the management of mental illnesses by virtue of their advantage over typical antipsychotics i.e. least tendency of producing extrapyramidal motor symptoms (EPS) or pseudoparkinsonism. Despite the clinical efficacy, AAPs produces troublesome adverse effects, particularly hyperphagia, hyperglycemia, dyslipidemia weight gain, diabetes mellitus, insulin resistance and QT prolongation which further develops metabolic and cardiac complications with subsequent reduction in life expectancy, poor patient compliance, and sudden death. AAPs-induced weight gain and metabolic alterations are increasing at an alarming rate and became an utmost matter of concern for psychopharmacotherapy. Diverse underlying mechanisms have been explored such as the interaction of AAPs with neurotransmitter receptors, alteration in food reward anticipation behavior, altered expressions of hypothalamic orexigenic and anorexigenic neuropeptides, histamine H₁ receptor-mediated hypothalamic AMP-activated protein kinase (AMPK) activation, increased blood leptin, ghrelin, pro-inflammatory cytokines. Antipsychotics induced imbalance in energy homeostasis, reduction in energy expenditure which is linked to altered expression of uncoupling proteins (UCP-1) in brown adipose tissue and reduced hypothalamic orexin expressions are emerging insights. In addition, alteration in gut-microbiota and subsequent inflammation, dyslipidemia, obesity, and diabetes after AAPs treatment are also associated with weight gain and metabolic alterations. Oral hypoglycemics and lipid-lowering drugs are mainly prescribed in the clinical management of weight gain associated with AAPs while many other pharmacological and nonpharmacological interventions also have been explored in different clinical and preclinical studies. In this review, we critically discuss the current scenario, mechanistic insights, biomarkers, and therapeutic alternatives for metabolic alterations associated with antipsychotics.

Betahistine effects on weight-related measures in patients treated with antipsychotic medications: a double-blind placebo-controlled study

RATIONALE

Weight gain during treatment with antipsychotics is a prominent side-effect, especially with some second-generation antipsychotics, such as olanzapine and clozapine, and pharmacological treatments which ameliorate this side-effect are important to investigate. Decreases in histaminergic transmission in the brain induced by antipsychotics may be one of the mechanisms contributing to weight gain. Since betahistine is a histaminergic agonist, it may potentially counteract the weight gain effects of antipsychotics.

METHOD

We conducted a double-blind placebo-controlled study to evaluate the effects of 12 weeks of treatment with betahistine (N = 29) or placebo (N = 22) in adolescents and adults on anthropomorphically measured weight-related parameters, appetite, and fasting glucose-lipid and leptin levels in 51 patients treated with first and/or second-generation antipsychotics who had gained weight during treatment or had high body-mass-index (BMI). Psychopathology and side-effects were also assessed with relevant scales.

RESULTS

In a sub-group of patients being treated with olanzapine or clozapine (n = 26), betahistine was significantly (P < .05) better than placebo in preventing increases in weight (3.1 kg less weight gain than placebo), BMI, and waist circumference. Betahistine did not decrease weight or BMI in patients treated with other antipsychotics. There was also no effect of betahistine on preventing weight or BMI gain in the total combined sample of all subjects. Betahistine did not significantly improve appetite or glucose-lipid measures in either subgroup. There were no significant differences in side-effects or psychopathology changes in the betahistine- vs. placebo-treated patients.

CONCLUSIONS

These results suggest that betahistine may potentially be a useful adjunctive drug for decreasing weight gain in patients treated with antipsychotics that are potent histamine antagonists, such as olanzapine or clozapine, but may not be useful for this purpose in patients on other antipsychotic medications. The results justify larger placebo-controlled studies to further confirm these effects before specific recommendations can be made for routine use.

Effect of Betahistine and Metformin on Antipsychotic-Induced Weight Gain: An Analysis of Two Clinical Trials

Antipsychotic-induced weight gain is one of the most common adverse effects of antipsychotic treatment. However, there are no well-established interventions for the weight gain yet. In this study, we pooled the data from two clinical trials, which were originally examining the efficacy of betahistine and the efficacy of metformin in treating antipsychotic-induced weight gain and insulin resistance. A total of 67 people with schizophrenia or bipolar disorder treated with antipsychotics were assigned to 36 mg day^-1 betahistine (n = 13) or 1,000 mg day^-1 metformin (n = 25) or placebo (n = 29) treatment for 12 weeks, with evaluation at baseline and week 12. The primary outcome was the body mass index (BMI). After treatment, metformin group had a mean decrease in BMI of 1.46 ± 0.14 (p < 0.001) and insulin resistance index (IRI) of 4.30 ± 2.02 (p < 0.001). The betahistine group had no significant alteration in BMI or IRI. However, placebo group had a mean increase in BMI of 1.27 ± 0.77 (p < 0.001) and IRI of 0.45 ± 0.86 (p < 0.001). Between the two treatment groups, metformin significantly decreased weight, BMI, fasting glucose, insulin level, and IRI but not waist circumference when compared with betahistine. Moreover, metformin significantly decreased weight, BMI, waist circumference, fasting glucose, insulin level, and IRI when compared with placebo, whereas betahistine significantly decreased body weight, waist circumference, BMI, insulin level, and IRI but not fasting glucose when compared with placebo. In this study, we found that both metformin treatment and betahistine treatment were efficacious in improving antipsychotic-induced weight gain and insulin resistance, and metformin was more efficacious in preventing and revising the weight gain induced by antipsychotics. Clinical Trial Registration: www.ClinicalTrials.gov, NCT00451399(Study 1), NCT00709202(Study 2).

Time-dependent effects of olanzapine treatment on the expression of histidine decarboxylase, H1 and H3 receptor in the rat brain: The roles in olanzapine-induced obesity

Antipsychotic treatment, particularly olanzapine and clozapine, induces severe obesity. The Histamine H1 receptor is considered to be an important contributor to olanzapine-induced obesity, however how olanzapine modulates the histaminergic system is not sufficiently understood. This study examined the effect of olanzapine on key molecules of the histaminergic system, including histidine decarboxylase (HDC), H1 receptor (H1R) and H3 receptor (H3R), in the brain at different stages of olanzapine-induced obesity. During short-term treatment (8-day), olanzapine increased hypothalamic HDC mRNA expression and H1R binding in the arcuate nucleus (Arc) and ventromedial hypothalamus (VMH), without changing H3R binding density. HDC mRNA and Arc H1R binding were positively correlated with increased food intake, feeding efficiency and weight gain. When the treatment was extended to 16 and 36 days, H1R binding was increased not only in the hypothalamic Arc and VMH but also in the brainstem dorsal vagal complex (DVC). The H1R bindings in the Arc, VMH and DVC were positively correlated with weight gain induced by olanzapine treatment. However, the expression of HDC and H3R mRNA was not increased. These results suggest that olanzapine time-dependently modulates histamine neurotransmission, which suggested the different neuronal mechanisms underlying different stages of weight gain development. Treatment targeting the H1R may be effective for both short- and long-term olanzapine-induced weight gain.

Efficacy of Metformin and Topiramate in Prevention and Treatment of Second-Generation Antipsychotic–Induced Weight Gain

Objective

To review the literature describing the efficacy of metformin and topiramate for the treatment of second-generation antipsychotio–induced weight gain.

Data sources

Articles were identified by searching the MEDLINE database (from 1949 through January 2010) using the key words metformin, topiramate, antipsychotic, weight, weight gain, and obesity.

Study selection and data extraction

All randomized, place bo-controlled trials of metformin and topiramate were selected for review.

Data synthesis

Weight gain due to second-generation antipsychotic use is a concern due to the risk of long-term metabolic and cardiovascular effects with these agents. These effects include obesity, hyperglycemia, and insulin resistance, all of which may contribute to diabetes and cardiovascular disease. Second-generation antipsychotics vary in the degree to which they cause weight gain, and dietary and lifestyle changes may not be feasible or sufficient in counteracting this weight gain. Although other pharmacologic agents may be beneficial to prevent and treat antipsychotic-induced weight gain, metformin and topiramate have been the most extensively studied in this setting. Metformin acts peripherally to cause weight loss, while topiramate acts centrally. Review of 11 randomized, controlled trials demonstrates beneficial effects of metformin and topiramate in prevention and treatment of weight gain. Metformin is generally well tolerated and has been studied in pediatric patients, while topiramate is associated with more drug interactions and may possibly interfere with control of schizophrenia.

Conclusions

Data for the use of metformin and topiramate in the treatment and prevention of second-generation antipsychotio–induced weight gain are limited. Both may be effective in helping patients lose weight via mechanisms that have yet to be clearly defined. The use of metformin results in greater weight loss than topiramate, and topiramate is associated with more risks and may compromise the treatment of schizophrenia. Treatment of antipsychotic-induced weight gain with metformin may be an option after lifestyle and dietary changes have failed.

Using Caenorhabditis elegans as a Model for Obesity Pharmacology Development

The Caenorhabditis elegans model is a rapid and inexpensive method to address pharmacologic questions. We describe the use of C. elegans to explore 2 pharmacologic questions concerning candidate antiobesity drugs and illustrate its potential usefulness in pharmacologic research: (1) to determine a ratio of betahistine-olanzapine that blocks the olanzapine-induced intestinal fat deposition (IFD) as detected by Nile red staining and (2) to identify the mechanism of action of a pharmaceutical candidate AB-101 that reduces IFD. Olanzapine (53 μg/mL) increased the IFD (12.1 ± 0.1%, P < 0.02), which was blocked by betahistine (763 μg/mL, 39.3 ± 0.01%, P < 0.05) in wild-type C. elegans (N2). AB-101 (1.0%) reduced the IFD in N2 (P < 0.05), increased the pharyngeal pumping rate (P < 0.05), and reversed the elevated IFD induced by protease inhibitors atazanavir and ritonavir (P < 0.05). AB-101 did not affect IFD in a ACS null mutant strain acs-4(ok2872) III/hT2[bli-4(e937) let-?(q782) qIs48](I;III) suggesting an involvement of the lipid oxidation pathway and an upregulation of CPT-1. Our studies suggest that C. elegans may be used as a resource in pharmacologic research. This article is intended to stimulate a greater appreciation of its value in the development of new pharmaceutical interventions.

A Randomized, Double-Blind, Placebo-Controlled Pilot Study of Betahistine to Counteract Olanzapine-Associated Weight Gain

Patients with schizophrenia experience higher rates of obesity and related morbidity and mortality than the general population does. Given preclinical studies revealing the role of histamine H1 receptor in human eating behavior, and the potential of olanzapine to block with this system, we hypothesized that histamine H1 receptor agonists may be beneficial in reducing antipsychotic-associated weight gain. In the present study, 36 patients with a diagnosis of schizophrenia or schizoaffective disorder and treated with olanzapine were randomized to betahistine (48 mg/d) or matching placebo for 16 weeks. Study outcomes were change in body weight from baseline and effect on antipsychotic efficacy of olanzapine. The patients in the betahistine group had less weight gain (-1.95 kg) compared with placebo group (5.6 + 5.5 kg vs 6.9 + 5.6 kg, respectively). Positive and Negative Syndrome Scale Questionnaire showed improvement within each group and that subjects treated with betahistine enjoyed an improvement (reduction) by a mean of 35.7 points, higher when compared with placebo subjects who had a reduction of 26.6 points (P = 0.233). An almost equal amount of subjects in both groups experienced adverse effects during the course of this study (87.5% of betahistine vs 85.0% of placebo-treated subjects). Overall, there were no clinically marked differences in safety signals between both groups. A larger study addressing the weaknesses of this pilot study is warranted.

Betahistine decreases olanzapine-induced weight gain and somnolence in humans

Olanzapine's efficacy in schizophrenia is attributed to antagonism of dopamine and serotonin receptors. Olanzapine is also a potent histamine-H1 antagonist that results in weight gain and somnolence. Betahistine is a centrally acting histamine-H1 agonist, and therefore may reduce olanzapine's effect on histamine receptors in the brain. Olanzapine's high affinity for the histamine-H1 receptor warrants the use of high doses of betahistine. Forty-eight healthy women were recruited and randomized to receive either betahistine 144 mg/day or matching placebo for 4 weeks. Due to the high dose of betahistine, olanzapine was started only on the second week and titrated up to 10 mg/day, and co-administration continued for an additional 2 weeks. Only nominal differences in adverse events were noted between the treatment groups. Betahistine caused a 37% reduction in mean weight gain (1.24 kg in the betahistine arm vs. 1.93 kg in the placebo arm; p=.049) and 60% reduction in the mean increase in daytime Epworth sleepiness scores (1.82 units in the betahistine group vs. 3.57 units in the placebo group; p=.042). The present study suggests that betahistine-olanzapine co-administration, in healthy female subjects, yields an acceptable safety profile with mitigation of weight gain and somnolence. This should be further tested in a patient cohort.

The histaminergic system as a target for the prevention of obesity and metabolic syndrome

The control of food intake and body weight is very complex. Key factors driving eating behavior are hunger and satiety that are controlled by an interplay of several central and peripheral neuroendocrine systems, environmental factors, the behavioral state and circadian rhythm, which all concur to alter homeostatic aspects of appetite and energy expenditure. Brain histamine plays a fundamental role in eating behavior as it induces loss of appetite and has long been considered a satiety signal that is released during food intake (Sakata et al., 1997). Animal studies have shown that brain histamine is released during the appetitive phase to provide a high level of arousal preparatory to feeding, but also mediates satiety. Furthermore, histamine regulates peripheral mechanisms such as glucose uptake and insulin function. Preclinical research indicates that activation of H1 and H3 receptors is crucial for the regulation of the diurnal rhythm of food consumption; furthermore, these receptors have been specifically recognized as mediators of energy intake and expenditure. Despite encouraging preclinical data, though, no brain penetrating H1 receptor agonists have been identified that would have anti-obesity effects. The potential role of the H3 receptor as a target of anti-obesity therapeutics was explored in clinical trials that did not meet up to the expectations or were interrupted (clinicaltrials.gov). Nonetheless, interesting results are emerging from clinical trials that evaluated the attenuating effect of betahistine (an H1 agonist/H3 antagonist) on metabolic side effects associated with chronic antipsychotics treatment. Aim of this review is to summarize recent results that suggest the clinical relevance of the histaminergic system for the treatment of feeding disorders and provide an up-to-date summary of preclinical research. This article is part of the Special Issue entitled 'Histamine Receptors'.

Chronic betahistine co-treatment reverses olanzapine's effects on dopamine D₂ but not 5-HT2A/2C bindings in rat brains

Olanzapine is widely prescribed for treating schizophrenia and other mental disorders, although it leads to severe body weight gain/obesity. Chronic co-treatment with betahistine has been found to significantly decrease olanzapine-induced weight gain; however, it is not clear whether this co-treatment affects the therapeutic effects of olanzapine. This study investigated the effects of chronic treatment of olanzapine and/or betahistine on the binding density of the serotonergic 5-HT2A (5-HT2AR) and 5-HT2C (5-HT2CR) receptors, 5-HT transporter (5-HTT), and dopaminergic D₂ receptors (D₂R) in the brain regions involved in antipsychotic efficacy, including the prefrontal cortex (PFC), cingulate cortex (Cg), nucleus accumbens (NAc), and caudate putamen (CPu). Rats were treated with olanzapine (1 mg/kg, t.i.d.) or vehicle for 3.5 weeks, and then olanzapine treatment was withdrawn for 19 days. From week 6, the two groups were divided into 4 groups (n=6) for 5 weeks' treatment: (1) olanzapine-only (1 mg/kg, t.i.d.), (2) betahistine-only (9.6 mg/kg, t.i.d.), (3) olanzapine and betahistine co-treatment (O+B), and (4) vehicle. Compared to the control, the olanzapine-only treatment significantly decreased the bindings of 5-HT2AR, 5-HT2CR, and 5-HTT in the PFC, Cg, and NAc. Similar changes were observed in the rats receiving the O+B co-treatment. The olanzapine-only treatment significantly increased the D₂R binding in the Cg, NAc, and CPu, while the betahistine-only treatment reduced D₂R binding. The co-treatment of betahistine reversed the D₂R bindings in the NAc and CPu that were increased by olanzapine. Therefore, chronic O+B co-treatment has similar effects on serotonin transmission as the olanzapine-only treatment, but reverses the D₂R that is up-regulated by chronic olanzapine treatment. The co-treatment maintains the therapeutic effects of olanzapine but decreases/prevents the excess weight gain.

Preventing olanzapine-induced weight gain using betahistine: a study in a rat model with chronic olanzapine treatment

Olanzapine is the one of first line antipsychotic drug for schizophrenia and other serious mental illness. However, it is associated with troublesome metabolic side-effects, particularly body weight gain and obesity. The antagonistic affinity to histamine H₁ receptors (H₁R) of antipsychotic drugs has been identified as one of the main contributors to weight gain/obesity side-effects. Our previous study showed that a short term (2 weeks) combination treatment of betahistine (an H₁R agonist and H₃R antagonist) and olanzapine (O+B) reduced (−45%) body weight gain induced by olanzapine in drug-naïve rats. A key issue is that clinical patients suffering with schizophrenia, bipolar disease and other mental disorders often face chronic, even life-time, antipsychotic treatment, in which they have often had previous antipsychotic exposure. Therefore, we investigated the effects of chronic O+B co-treatment in controlling body weight in female rats with chronic and repeated exposure of olanzapine. The results showed that co-administration of olanzapine (3 mg/kg, t.i.d.) and betahistine (9.6 mg/kg, t.i.d.) significantly reduced (−51.4%) weight gain induced by olanzapine. Co-treatment of O+B also led to a decrease in feeding efficiency, liver and fat mass. Consistently, the olanzapine-only treatment increased hypothalamic H₁R protein levels, as well as hypothalamic pAMPKα, AMPKα and NPY protein levels, while reducing the hypothalamic POMC, and UCP₁ and PGC-1α protein levels in brown adipose tissue (BAT). The olanzapine induced changes in hypothalamic H₁R, pAMPKα, BAT UCP₁ and PGC-1α could be reversed by co-treatment of O+B. These results supported further clinical trials to test the effectiveness of co-treatment of O+B for controlling weight gain/obesity side-effects in schizophrenia with chronic antipsychotic treatment.

Recent evidence and potential mechanisms underlying weight gain and insulin resistance due to atypical antipsychotics

OBJECTIVE

Atypical antipsychotics (AAPs) promote obesity and insulin resistance. In this regard, the main objective of this study was to present potential mechanisms and evidence concerning side effects of atypical antipsychotics in humans and rodents.

METHOD

A systematic review of the literature was performed using the MEDLINE database. We checked the references of selected articles, review articles, and books on the subject.

RESULTS

This review provides consistent results concerning the side effects of olanzapine (OL) and clozapine (CLZ), whereas we found conflicting results related to other AAPs. Most studies involving humans describe the effects on body weight, adiposity, lipid profile, and blood glucose levels. However, it seems difficult to identify an animal model replicating the wide range of changes observed in humans. Animal lineage, route of administration, dose, and duration of treatment should be carefully chosen for the replication of the findings in humans.

CONCLUSIONS

Patients undergoing treatment with AAPs are at higher risk of developing adverse metabolic changes. This increased risk must be taken into account when making decisions about treatment. The influence of AAPs on multiple systems is certainly the cause of such effects. Specifically, muscarinic and histaminergic pathways seem to play important roles.

Hypothalamic histamine H1 receptor-AMPK signaling time-dependently mediates olanzapine-induced hyperphagia and weight gain in female rats

Although second-generation antipsychotics induce severe weight gain and obesity, there is a lack of detailed knowledge about the progressive development of antipsychotic-induced obesity. This study examined the hypothalamic histamine H1 receptor and AMP-activated protein kinase (H1R-AMPK) signaling at three distinctive stages of olanzapine-induced weight gain (day 1-12: early acceleration, day 13-28: middle new equilibrium, and day 29-36: late heavy weight maintenance). At the early acceleration stage, the rats were hyperphagic with an underlying mechanism of olanzapine-increased H1R mRNA expression and AMPK phosphorylation (pAMPK), in which pAMPK levels positively correlated with H1R mRNA expression and food intake. At the middle stage, when the rats were no longer hyperphagic, the changes in H1R-AMPK signaling vanished. At the late stage, olanzapine increased H1R mRNA expression but decreased pAMPK which were positively and negatively correlated with weight gain, respectively. These data suggest a time-dependent change of H1R-AMPK signaling, where olanzapine activates AMPK by blocking the H1Rs and causing hyperphagia in the acute phase. The chronic blockade of H1R may contribute to the late stage of olanzapine-induced heavy weight maintenance. However, pAMPK was no longer elevated and actually decreased. This indicates that AMPK acts as an energy sensor and negatively responds to the positive energy balance induced by olanzapine. Furthermore, we showed that an H1R agonist, 2-(3-trifluoromethylphenyl) histamine, can significantly inhibit olanzapine-induced hyperphagia and AMPK activation in the mediobasal hypothalamus in a dose dependent manner. Therefore, lowering H1R-AMPK signaling is an effective treatment for the olanzapine-induced hyperphagia associated with the development of obesity.

Effects of olanzapine and betahistine co-treatment on serotonin transporter, 5-HT2A and dopamine D2 receptor binding density

Olanzapine is widely used in treating multiple domains of schizophrenia symptoms but induces serious metabolic side-effects. Recent evidence has showed that co-treatment of betahistine (a histaminergic H1 receptor agonist and H3 receptor antagonist) is effective for preventing olanzapine-induced weight gain/obesity, however it is not clear whether this co-treatment affects on the primary therapeutic receptor binding sites of olanzapine such as serotonergic 5-HT2A receptors (5-HT2AR) and dopaminergic D2 receptors (D2R). Therefore, this study investigated the effects of this co-treatment on 5-HT2AR, 5-HT transporter (5-HTT) and D2R bindings in various brain regions involved in antipsychotic efficacy. Female Sprague Dawley rats were administered orally (t.i.d.) with either olanzapine (1mg/kg), betahistine (2.7 mg/kg), olanzapine plus betahistine (O+B), or vehicle (control) for 2 weeks. Quantitative autoradiography was used to detect the density of [(3)H]ketanserin, [(3)H]paroxetine and [(3)H]raclopride binding site to 5-HT2AR, 5-HTT and D2R. Compared to the controls, olanzapine significantly decreased [(3)H]ketanserin bindings to 5-HT2AR in the prefrontal cortex, cingulate cortex, and nucleus accumbens. Similar changes in 5-HT2AR bindings in these nuclei were also observed in the O+B co-treatment group. Olanzapine also significantly decreased [(3)H]paroxetine binding to 5-HTT in the ventral tegmental area and substantia nigra, however, both olanzapine only and O+B co-treatment did not affect [(3)H]raclopride binding to D2R. The results confirmed the important role of 5-HT2AR in the efficacy of olanzapine, which is not influenced by the O+B co-treatment. Therefore, betahistine co-treatment would be an effective combination therapy to reduce olanzapine-induced weight gain side-effects without affecting olanzapine's actions on 5-HT2AR transmissions.

Effects of antipsychotic medications on appetite, weight, and insulin resistance

Although clozapine, olanzapine, and other atypical antipsychotic drugs (APDs) have fewer extrapyramidal side effects, they have serious metabolic side effects such as substantial weight gain, intra-abdominal obesity, and type 2 diabetes mellitus. Given that most patients with mental disorders face chronic, even life-long, treatment with APDs, the risks of weight gain/obesity and other metabolic symptoms are major considerations for APD maintenance treatment. This review focuses on the effects of APDs on weight gain, appetite, insulin resistance, and glucose dysregulation, and the relevant underlying mechanisms that may be help to prevent and treat metabolic side effects caused by APD therapy.

The role of hypothalamic H1 receptor antagonism in antipsychotic-induced weight gain

Treatment with second generation antipsychotics (SGAs), notably olanzapine and clozapine, causes severe obesity side effects. Antagonism of histamine H1 receptors has been identified as a main cause of SGA-induced obesity, but the molecular mechanisms associated with this antagonism in different stages of SGA-induced weight gain remain unclear. This review aims to explore the potential role of hypothalamic histamine H1 receptors in different stages of SGA-induced weight gain/obesity and the molecular pathways related to SGA-induced antagonism of these receptors. Initial data have demonstrated the importance of hypothalamic H1 receptors in both short- and long-term SGA-induced obesity. Blocking hypothalamic H1 receptors by SGAs activates AMP-activated protein kinase (AMPK), a well-known feeding regulator. During short-term treatment, hypothalamic H1 receptor antagonism by SGAs may activate the AMPK-carnitine palmitoyltransferase 1 signaling to rapidly increase caloric intake and result in weight gain. During long-term SGA treatment, hypothalamic H1 receptor antagonism can reduce thermogenesis, possibly by inhibiting the sympathetic outflows to the brainstem rostral raphe pallidus and rostral ventrolateral medulla, therefore decreasing brown adipose tissue thermogenesis. Additionally, blocking of hypothalamic H1 receptors by SGAs may also contribute to fat accumulation by decreasing lipolysis but increasing lipogenesis in white adipose tissue. In summary, antagonism of hypothalamic H1 receptors by SGAs may time-dependently affect the hypothalamus-brainstem circuits to cause weight gain by stimulating appetite and fat accumulation but reducing energy expenditure. The H1 receptor and its downstream signaling molecules could be valuable targets for the design of new compounds for treating SGA-induced weight gain/obesity.

Reducing antipsychotic-induced weight gain in schizophrenia: a double-blind placebo-controlled study of reboxetine-betahistine combination

RATIONALE

Combination treatment with reboxetine, a selective norepinephrine reuptake inhibitor, and betahistine, a histamine H1 receptor agonist/H3 antagonist, was developed to produce complementary action in CNS pathways regulating appetite and body weight. In the present placebo-controlled study, we evaluated whether a reboxetine-betahistine combination attenuates olanzapine-induced weight gain in schizophrenia patients.

METHOD

Forty-three inpatients with DSM-IV schizophrenic disorder participated in a randomized double-blind study. Reboxetine (4 mg/day) with betahistine (48 mg/day) (N = 29) or placebo (N = 14) was co-administered with olanzapine (10 mg/day) for 6 weeks. Mental status was assessed at baseline and endpoint with relevant rating scales. Intention-to-treat method was used for statistical analysis.

RESULTS

Seven patients in the study group and four in the placebo group discontinued the trial. At the end of the trial, patients in the olanzapine/reboxetine + betahistine group gained significantly less weight than those in the olanzapine/placebo group [2.02 ± 2.37 and 4.77 ± 3.16 kg, respectively; t = 2. 89, degrees of freedom (df) = 41, p = 0.006]. The weight-attenuating effect of this combination was twofold larger than the weight-attenuating effect previously demonstrated with reboxetine alone. Significantly fewer patients in the study group than in the comparison group increased their initial weight by >7 %, the cutoff for clinically significant weight gain [3/29 (10.3 %) and 6/14 (42.9 %), respectively; χ (2) = 6.03, df = 1, p = 0.014]. The reboxetine-betahistine combination was safe and well tolerated.

CONCLUSIONS

Reboxetine-betahistine combination produces a clinically meaningful attenuation of olanzapine-induced weight gain. These results justify direct comparison between the reboxetine-betahistine combination and reboxetine alone.

Reducing olanzapine-induced weight gain side effect by using betahistine: a study in the rat model

Olanzapine is effective at treating multiple domains of schizophrenia symptoms. However, it induces serious metabolic side effects. Antipsychotic drug's antagonistic affinity to histamine H₁ receptors has been identified as a main contributor for weight gain/obesity side effects. This study therefore investigated whether a combined treatment of betahistine (a H₁ receptor agonist and H₃ receptor antagonist) could reduce the body weight/obesity induced by olanzapine. Female Sprague Dawley rats were treated orally with olanzapine (1 mg/kg, t.i.d.) and/or betahistine (2.67 mg/kg, t.i.d.), or vehicle for two weeks. Rats treated with olanzapine exhibited significant body weight gain and increased food intake. Co-treatment of olanzapine with betahistine significantly prevented (-45%) weight gain and reduced feeding efficiency compared to sole olanzapine treatment. Betahistine treatment alone had no effect on weight gain and food intake. Olanzapine reduced locomotor activity, but not betahistine. These findings demonstrate that olanzapine-induced body weight gain can partially be reduced by co-treatment with betahistine. Betahistine has H₃ receptor antagonistic effects to increase histamine release, which may augment its direct agonistic effects on H₁ receptors. These findings have important implications for clinical trials using betahistine to control antipsychotic-induced obesity side effects.

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.

Acute effects of betahistine hydrochloride on food intake and appetite in obese women: a randomized, placebo-controlled trial

BACKGROUND

Central nervous system histaminergic tone is thought to play a role in appetite regulation. In animal models, histamine receptor 1 (HRH1) agonists and histamine receptor 3 (HRH3) antagonists decrease food intake.

OBJECTIVE

The objective of this study was to examine the acute effects of betahistine hydrochloride (an HRH1 agonist and HRH3 antagonist) on food intakes and appetites.

DESIGN

The study was a proof-of-concept, randomized, double-blinded, placebo-controlled, dose-ranging study performed to examine the effects of betahistine in women with class I or II obesity [body mass index (BMI; in kg/m²) of 30-39.99]. After a 24-h placebo run-in period, subjects received a placebo (n = 19) or 48 (n = 19), 96 (n = 17), or 144 (n = 21) mg betahistine/d for 24 h. Treatment was followed by a buffet test meal to assess energy intake. Hunger, satiety, and desire to eat were measured after consuming the meal by using visual analog scales. Data were analyzed by using regression models with the assumption that there would be an increasing effect of betahistine doses. Analyses were adjusted for age, log fat and lean mass, food preferences, and intake during a buffet test meal obtained during the placebo run-in period.

RESULTS

Of the 79 obese women (mean ± SD age: 42 ± 11 y; BMI: 35 ± 3) enrolled in the study, 76 women completed the study. The betahistine dose did not significantly change intakes from those observed during the run-in period of the buffet test meal (P = 0.78). Hunger, fullness, and desire to eat (all P > 0.62) similarly showed no differences according to the betahistine dose.

CONCLUSIONS

Betahistine did not produce an effect on food intakes or appetites. More potent histaminergic modulators may be required to elucidate the possible role of histaminergic pathways in human obesity. This trial was registered at clinicaltrials.gov as NCT00459992.

The histamine H3 receptor and eating behavior

Interest in the histaminergic system as a potential target for the treatment of feeding disorders is driven by the unsatisfactory history of the pharmacotherapy of obesity. Eating behavior is regulated by a complex interplay of central neurotransmitter systems, peripheral endocrine stimuli, the circadian rhythm, and environmental cues, all factors that change the behavioral state and alter homeostatic aspects of appetite and energy expenditure. Key factors driving eating behavior are appetite and satiety that are regulated through different mechanisms. Brain histamine has long been considered a satiety signal in the nervous system. Recent observations, however, indicate that histamine does not meet the criteria for being a satiety signal, because augmented histamine release accompanies the appetitive phase of feeding behavior rather than food consumption and satiety. The appetitive phase requires a high and yet optimal arousal state, and the histaminergic system is crucial for sustaining a high degree of arousal during motivated behavior. Histamine H(1) receptors in the brain are crucial for the regulation of the diurnal rhythm of food intake and the regulation of obesity; however, from a therapeutic standpoint, no brain-penetrating H(1) receptor agonists have been identified that would have antiobesity effects. Despite conflicting preclinical data, insights are emerging into the potential role of histamine H(3) receptors as a target of antiobesity therapeutics. The aim of this review is to outline the relevance of the histaminergic system in controlling feeding behavior and evaluate the potential therapeutic use of histaminergic ligands for the treatment of eating disorders.

Beneficial effect of the insulin sensitizer (HSP inducer) BGP-15 on olanzapine-induced metabolic disorders

Olanzapine is a widely used atypical antipsychotic, with well known metabolic side effects such as weight gain, insulin resistance and blood glucose abnormalities. It has been previously shown in a phase II clinical trial that BGP-15, an amidoxim derivative has insulin-sensitizing effects. The aim of this study was to investigate the efficacy of BGP-15 for the treatment of olanzapine-induced metabolic side effects, in healthy volunteers. Thirty-seven (37) subjects (ages 18-55 years) with normal glucose metabolism were randomly assigned to 17 days of once-daily treatment with 400mg of BGP-15 or placebo and 5mg of olanzapine for 3 days followed by 10mg for 14 days. Total body and muscle tissue glucose utilization was determined by hyperinsulinemic-euglycemic clamp technique. As expected the 17-day olanzapine treatment provoked insulin resistance and body weight gain (p<0.05) in both groups. Administration of BGP-15 significantly reduced olanzapine-induced insulin resistance. The protective effect of BGP-15 on insulin stimulated glucose utilization had the highest magnitude in the values calculated for the muscle tissue (p=0.002). In healthy individuals BGP-15 was safe and well tolerated during the whole study period. It is suggested that BGP-15 can be a successful insulin sensitizer agent to prevent side effects of olanzapine treatment.

Induction of subcutaneous adipose proliferation by olanzapine in rodents

Weight gain induced by atypical antipsychotics causes a serious health concern in the treatment of schizophrenic patients. In the present study chronic treatment of female Wistar rats with olanzapine caused weight gain, but limited effect on food intake. A dramatic drug-induced morphological change of the subcutaneous adipose tissue was observed, i.e. development of a pinkish coloration with the appearance of a "fish egg"-like texture. Histological examination revealed a massive increase in the proliferation of undifferentiated adipocytes. Such proliferation was detected as early as the third day after olanzapine treatment. The changes progressed in a time- and dose-dependent manner. The proliferation of adipose tissue was detected in rats treated with olanzapine independent of increases in weight gain. Protein profiles of the adipose tissue were also altered by olanzapine. These results suggest that olanzapine-induced weight gain may be not solely due to an effect on behavioural satiety. The potential involvement of adipose neuronal input and proliferation are discussed.

Adiposopathy: treating pathogenic adipose tissue to reduce cardiovascular disease risk

Excessive adipose tissue is potentially pathogenic due to its mass effects and through adverse metabolic/immune responses, which may lead to cardiovascular disease risk factors (eg, type 2 diabetes mellitus, hypertension, dyslipidemia, and possibly atherosclerosis itself). Positive caloric balance in genetically/environmentally susceptible patients may result in adipocyte hypertrophy, visceral adipose tissue accumulation, and ectopic fat deposition, all causally associated with metabolic disease, and all anatomic manifestations of "adiposopathy" (a term used to describe adipose tissue pathology). Weight loss through improved nutrition, increased physical activity, and weight loss agents (ie, orlistat and sibutramine) improves adiposopathy and improves many metabolic diseases whose prevalence are directly associated with an increase in body fat and sedentary lifestyle. Cannabinoid receptor antagonists improve adiposopathy through weight reduction and favorable metabolic effects upon multiple body organs (including adipocytes). Peroxisome proliferator-activated receptor-gamma agonists may improve adiposopathy through recruitment of functional fat cells and apoptosis of dysfunctional fat cells.

The role of histaminergic H1 and H3 receptors in food intake: a mechanism for atypical antipsychotic-induced weight gain?

Atypical antipsychotics such as olanzapine and clozapine are effective at treating the multiple domains of schizophrenia, with a low risk of extra-pyramidal side-effects. However a major downfall to their use is metabolic side-effects particularly weight gain/obesity, which occurs by unknown mechanisms. The present paper explores the potential candidature of histaminergic neurotransmission in the mechanisms of atypical antipsychotic-induced weight gain, with a focus on the histaminergic H1 and H3 receptors. Olanzapine and clozapine have a high affinity for the H1 receptor, and meta-analyses show a strong correlation between risk of weight gain and H1 receptor affinity. In addition, olanzapine treatment decreases H1 receptor binding and mRNA expression in the rat hypothalamus. Furthermore, a complex role is emerging for the histamine H3 receptor in the control of hunger. The H3 receptor is a pre-synaptic autoreceptor that inhibits the synthesis and release of histamine, and a heteroreceptor that inhibits other neurotransmitters such as serotonin (5-HT), noradrenaline (NA) and acetylcholine (ACh), which are also implicated in the regulation of food intake. Thus, the H3 receptor is in a prime position to regulate food intake, both through its control of histamine and its influence on other feeding pathways. We proposed that a mechanism for atypical antipsychotic-induced weight gain may be partly through the H3 receptor, as a drug-induced decrease in H1 receptor activity may decrease histamine tone through the H3 autoreceptors, compounding the weight gain problem. In addition, atypical antipsychotics may affect food intake by influencing 5-HT, NA and ACh release via interactions with the H3 heteroreceptor.

Mifepristone treatment of olanzapine-induced weight gain in healthy men

INTRODUCTION

Antipsychotic medications are associated with significant weight gain, type 2 diabetes mellitus, dyslipidemia, and increased cardiovascular risk. Suggested mechanisms of weight gain from antipsychotic medication include antagonism of histamine and serotonin receptors, and effects on the hypothalamic-pituitary-adrenal axis. The objective of this study was to determine if mifepristone, a glucocorticoid receptor antagonist, could prevent olanzapine-induced weight gain.

METHODS

This was a randomized, double-blind trial. Fifty-seven lean, healthy men (body mass index 18-25 kg/m(2)) aged 19-38 years were randomized to olanzapine (7.5 mg) (n=22), olanzapine (7.5 mg) plus mifepristone (600 mg) (n=24), or mifepristone (600 mg) (n=11) daily for 2 weeks in an institutional setting. Subjects were provided food ad libitum to accentuate weight gain. Body weight was measured daily.

RESULTS

The mean change in baseline weight was +3.2+/-0.9 kg in subjects receiving olanzapine versus +2.0+/-1.2 kg in those receiving olanzapine plus mifepristone (P<0.0001). Subjects receiving mifepristone alone had a similar degree of weight gain compared to those receiving olanzapine plus mifepristone. The olanzapine group had significant increases in waist circumference when compared with the olanzapine plus mifepristone group (3.7+/-1.3 cm vs. 2.2+/-1.9 cm, respectively; P=0.006). Fasting insulin and triglycerides increased more in the olanzapine group, although differences were not statistically significant.

CONCLUSION

Mifepristone was effective in attenuating the increase in weight associated with olanzapine treatment over a 2-week period. Longer-term studies are required to examine the durability and full magnitude of this response.

Obesity, serious mental illness and antipsychotic drugs

The prevalence of overweight and obesity is higher in people with mental illness than in the general population. Body weight is tightly regulated by a complex system involving the cortex and limbic system, the hypothalamus and the gastrointestinal tract. While there are justifiable concerns about the weight gain associated with antipsychotic medication, it is too simplistic to ascribe all obesity in people with serious mental illness (SMI) to their drug treatment. The development of obesity in SMI results from the complex interaction of the genotype and environment of the person with mental illness, the mental illness itself and antipsychotic medication. There are dysfunctional reward mechanisms in SMI that may contribute to poor food choices and overeating. While it is clear that antipsychotics have profound effects to stimulate appetite, no one receptor interaction provides an adequate explanation for this effect, and many mechanisms are likely to be involved. The complexity of the system regulating body weight allows us to start to understand why some individuals appear much more prone to weight gain and obesity than others.

Insulin resistance and secretion in vivo: effects of different antipsychotics in an animal model

Atypical antipsychotics now represent the mainstay of treatment for patients with schizophrenia. Unfortunately, as a class they have also been associated with an increased risk of weight gain and metabolic abnormalities, including type 2 diabetes. We have investigated the diabetogenic effects of a spectrum of antipsychotics, both atypical and typical. Healthy animals were treated acutely with clozapine (10 mg/kg), olanzapine (3.0 mg/kg), risperidone (1 mg/kg), ziprasidone (3 mg/kg) or haloperidol (0.25 mg/kg) and tested using the hyperinsulinemic-euglycemic and hyperglycemic clamp procedures. Clozapine and olanzapine had a rapid and potent effect on insulin sensitivity by lowering the glucose infusion rate and increasing hepatic glucose production. Both clozapine and olanzapine, as well as risperidone, decreased peripheral glucose utilization. Neither ziprasidone nor haloperidol had a significant impact on insulin sensitivity. In the hyperglycemic clamp, clozapine and olanzapine impaired beta cell function as reflected by a decrease in insulin secretion. Results confirm that 1) antipsychotic medications have an immediate impact on metabolic parameters and 2) the various atypical antipsychotics differ in their propensity to acutely induce metabolic side effects. Our data also support the preclinical use of these clamp procedures in screening putative antipsychotics.

Effects of clozapine and olanzapine on cytokine systems are closely linked to weight gain and drug-induced fever

The second generation antipsychotics clozapine and olanzapine are known to cause weight gain. However, only clozapine is associated with drug-induced fever. Cytokines have been linked to the induction of both weight gain and drug-induced fever. We investigated these potential side effects of clozapine and olanzapine and studied their differential effects on cytokine secretion. Thirty patients suffering from schizophrenia, schizophreniform disorder or schizoaffective disorder were treated with either clozapine (mean modal dose: 266.7+/-77.9mg) or olanzapine (21.2+/-2.5mg) in a randomized, double-blind, 6-week study. Body mass index (BMI), tympanic temperature, and plasma levels of leptin and cytokines (tumor necrosis factor-alpha (TNF-alpha), soluble TNF receptor 1 and 2 (sTNFR-1/2), soluble interleukin-2 receptors (sIL-2R), interleukin-6) were determined weekly. BMI, leptin and cytokines significantly increased over time, except interleukin-6 and sTNFR-1 in the olanzapine group. All cytokines numerically increased compared to baseline already during the first week of treatment in both groups. Leptin, TNF-alpha, sTNFR-1, sTNFR-2 and sIL-2R levels correlated with the BMI. Five patients who received clozapine (33%) developed drug-induced fever (>/=38 degrees C). In these, interleukin-6 peak levels were significantly (p<0.01) higher than in those patients treated with clozapine who did not develop fever. In conclusion, increase of BMI appears to be related to clozapine's and olanzapine's similar effects on cytokine systems, whilst drug-induced fever appears to be related to clozapine's differential effects on interleukin-6.

Pharmacological management of atypical antipsychotic-induced weight gain

Excessive bodyweight gain was reported during the 1950s as an adverse effect of typical antipsychotic drug treatment, but the magnitude of bodyweight gain was found to be higher with the atypical antipsychotic drugs that were introduced after 1990. Clozapine and olanzapine produce the greatest bodyweight gain, ziprasidone and aripiprazole have a neutral influence, and quetiapine and risperidone cause an intermediate effect. In the CATIE study, the percentage of patients with bodyweight gain of >7% compared with baseline differed significantly between the antipsychotic drugs, i.e. 30%, 16%, 14%, 12% and 7% for olanzapine, quetiapine, risperidone, perphenazine (a typical antipsychotic) and ziprasidone, respectively (p<0.001). Appetite stimulation is probably a key cause of bodyweight gain, but genetic polymorphisms modify the bodyweight response during treatment with atypical antipsychotics. In addition to nutritional advice, programmed physical activity, cognitive-behavioural training and atypical antipsychotic switching, pharmacological adjunctive treatments have been assessed to counteract excessive bodyweight gain. In some clinical trials, nizatidine, amantadine, reboxetine, topiramate, sibutramine and metformin proved effective in preventing or reversing atypical antipsychotic-induced bodyweight gain; however, the results are inconclusive since few randomized, placebo-controlled clinical trials have been conducted. Indeed, most studies were short-term trials without adequate statistical power and, in the case of metformin, nizatidine and sibutramine, the results are contradictory. The tolerability profile of these agents is adequate. More studies are needed before formal recommendations on the use of these drugs can be made. Meanwhile, clinicians are advised to use any of these adjunctive treatments according to their individual pharmacological and tolerability profiles, and the patient's personal and family history of bodyweight gain and metabolic dysfunction.

Short- and long-term effects of antipsychotic drug treatment on weight gain and H1 receptor expression

The present study investigated body weight gain, food intake, open-field activity and brain histamine H1 receptor mRNA and protein expression in rats treated with three types of antipsychotics. Rats were divided into eight groups and treated with aripiprazole (2.25mg/kg/day), olanzapine (1.5mg/kg/day), haloperidol (0.3mg/kg/day) or vehicle (as control) for 1 or 12 weeks. Administration of olanzapine for 1 week led to a threefold increase in body weight gain and a 35% increase in fat deposits compared to controls (p<0.05). In the 12-week olanzapine treatment group, accumulative food intake was significantly higher in the first 7 weeks of treatment compared to controls (p<0.018), while body weight gain was significantly greater in the first 8 weeks compared to controls (p<0.045). Using in situ hybridization, we found that olanzapine treatment, but not aripiprazole or haloperidol treatment, significantly reduced H1 receptor mRNA expression in the arcuate hypothalamic nucleus (Arc: -18%, p=0.006, 1 week; -20%, p=0.008, 12 weeks) and ventromedial hypothalamic nucleus (VMH: -22%, p=0.006, 1 week; -19%, p=0.042, 12 weeks) compared to controls. The quantitative autoradiography data showed a reduction in VMH H1 receptor binding density after 1 (-12%, p=0.040) and 12 (-10%, p=0.094) weeks of olanzapine treatment. There were significant negative correlations between the levels of H1 receptor mRNA expression, and body weight gain and energy efficiency in the Arc and VMH after 1- and 12-week antipsychotic treatments in all groups. In addition, H1 receptor mRNA expression in the Arc showed a significant negative correlation with food intake and fat mass in all groups. Furthermore, there were negative correlations between H1 receptor binding density in the VMH and total fat mass and body weight gain after 1 week of antipsychotic treatment. The present study suggests that downregulated VMH and Arc H1 receptor expression may be a key factor contributing to olanzapine-induced obesity.

An overview of obesity in children with psychiatric disorders taking atypical antipsychotics

BACKGROUND

Children with psychiatric illness are at greater risk for obesity than those in the general population. In part, this greater risk is due to the escalating use of psychotropic medications. Second-generation antipsychotics effectively treat mental illness but are associated with weight gain. Data for management of obesity in this population is lacking.

METHODS

Articles on obesity, mental illness, and obesity management were reviewed. Keywords included children, adolescents, obesity, weight gain, psychiatric illness, therapy, treatment, and antipsychotic.

RESULTS

For pediatric obesity, educational, nutritional, behavioral, and family-based interventions were identified as nonpharmacological interventions. All nonpharmacological modalities indicate modest to moderate success in weight control or loss. Pharmacological agents, alone or with diet and exercise, appear promising in obesity management.

CONCLUSION

Since there are limited intervention studies available for obese children with psychiatric illness, general childhood obesity studies may be referenced for trials in this population. Long-term efficacy and safety of these interventions are not yet available. Methodological constraints of prior studies include small sample sizes and the absence of randomized, placebo-controlled, and longitudinal trials - highlighting the need for further trials addressing these issues. Clinical monitoring and management of medication-induced obesity remains an important public health concern.

Multi-modal weight control intervention for people with persistent mental disorders

Obesity, a major problem worldwide, is more prevalent among people with schizophrenia. This study examined the effect of behavior intervention, nutritional information and physical exercise on the body mass index (BMI) and weight of people who were hospitalized with persistent DSM-IV schizophrenia and schizoaffective disorders. Fifty nine inpatients with a BMI greater than 25 participated, (28 intervention group; 31 control group). Significant reductions in BMI and weight were observed in the intervention group after 3 months and were maintained 1-year post study [F(1,52) = 6.1, p = .017) and F(1,52) = 3.7, P = .006, respectively]. If provided with adequate information and an appropriate framework, people with persistent schizophrenia can significantly reduce BMI and weight and maintain the loss.

Atypical antipsychotic-induced metabolic side effects: insights from receptor-binding profiles

Atypical antipsychotic drugs offer several notable benefits over typical antipsychotics, including greater improvement in negative symptoms, cognitive function, prevention of deterioration, and quality of life, and fewer extrapyramidal symptoms (EPS). However, concerns about EPS have been replaced by concerns about other side effects, such as weight gain, glucose dysregulation and dyslipidemia. These side effects are associated with potential long-term cardiovascular health risks, decreased medication adherence, and may eventually lead to clinical deterioration. Despite a greater understanding of the biochemical effects of these drugs in recent years, the pharmacological mechanisms underlying their various therapeutic properties and related side effects remain unclear. Besides dopamine D(2) receptor antagonism, a characteristic feature of all atypical antipsychotic drugs, these agents also bind to a range of non-dopaminergic targets, including serotonin, glutamate, histamine, alpha-adrenergic and muscarinic receptors. This review examines the potential contribution of different receptors to metabolic side effects associated with atypical antipsychotic treatment for all seven agents currently marketed in the United States (risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole, paliperidone and clozapine) and another agent (bifeprunox) in clinical development at the time of this publication.