Olanzapine-associated dose-dependent alterations for weight and metabolic parameters in a prospective cohort

Olanzapine, but not haloperidol, exerts pronounced acute metabolic effects in the methylazoxymethanol rat model

AIM

Widely used second-generation antipsychotics are associated with adverse metabolic effects, contributing to increased cardiovascular mortality. To develop strategies to prevent or treat adverse metabolic effects, preclinical models have a clear role in uncovering underlying molecular mechanisms. However, with few exceptions, preclinical studies have been performed in healthy animals, neglecting the contribution of dysmetabolic features inherent to psychotic disorders.

METHODS

In this study, methylazoxymethanol acetate (MAM) was prenatally administered to pregnant Sprague-Dawley rats at gestational day 17 to induce a well-validated neurodevelopmental model of schizophrenia mimicking its assumed pathogenesis with persistent phenotype. Against this background, the dysmetabolic effects of acute treatment with olanzapine and haloperidol were examined in female rats.

RESULTS

Prenatally MAM-exposed animals exhibited several metabolic features, including lipid disturbances. Half of the MAM rats exposed to olanzapine had pronounced serum lipid profile alteration compared to non-MAM controls, interpreted as a reflection of a delicate MAM-induced metabolic balance disrupted by olanzapine. In accordance with the drugs' clinical metabolic profiles, olanzapine-associated dysmetabolic effects were more pronounced than haloperidol-associated dysmetabolic effects in non-MAM rats and rats exposed to MAM.

CONCLUSION

Our results demonstrate metabolic vulnerability in female prenatally MAM-exposed rats, indicating that findings from healthy animals likely provide an underestimated impression of metabolic dysfunction associated with antipsychotics. In the context of metabolic disturbances, neurodevelopmental models possess a relevant background, and the search for adequate animal models should receive more attention within the field of experimental psychopharmacology.

Controversies regarding lithium-associated weight gain: case-control study of real-world drug safety data

BACKGROUND

The impact of long-term lithium treatment on weight gain has been a controversial topic with conflicting evidence. We aim to assess reporting of weight gain associated with lithium and other mood stabilizers compared to lamotrigine which is considered free of metabolic adverse drug reactions (ADRs).

METHODS

We conducted a case/non-case pharmacovigilance study using data from the AMSP project (German: "Arzneimittelsicherheit in der Psychiatrie"; i.e., Drug Safety in Psychiatry), which collects data on ADRs from patients treated in psychiatric hospitals in Germany, Austria, and Switzerland. We performed a disproportionality analysis of reports of weight gain (> 10% of baseline body weight) calculating reporting odds ratio (ROR). We compared aripiprazole, carbamazepine, lithium, olanzapine, quetiapine, risperidone, and valproate to lamotrigine. Additional analyses related to different mood stabilizers as reference medication were performed. We also assessed sex and age distributions of weight-gain reports.

RESULTS

We identified a total of 527 cases of severe drug-induced weight gain representing 7.4% of all severe ADRs. The ROR for lithium was 2.1 (95%CI 0.9-5.1, p > 0.05), which did not reach statistical significance. Statistically significant disproportionate reporting of weight gain was reported for olanzapine (ROR: 11.5, 95%CI 4.7-28.3, p < 0.001), quetiapine (ROR: 3.4, 95%CI 1.3-8.4, p < 0.01), and valproate (ROR: 2.4, 95%CI 1.1-5.0, p = 0.03) compared to lamotrigine. Severe weight gain was more prevalent in non-elderly (< 65 years) than in elderly patients, with an ROR of 7.6 (p < 0.01) in those treated with lithium, and an ROR of 14.7 (p < 0.01) in those not treated with lithium.

CONCLUSIONS

Our findings suggest that lithium is associated with more reports of severe weight gain than lamotrigine, although this difference did not reach statistical significance. However, lithium use led to fewer reports of severe weight gain than some alternative drugs for long-term medication (olanzapine, quetiapine, and valproate), which is consistent with recent studies. Monitoring of weight gain and metabolic parameters remains essential with lithium and its alternatives.

Longitudinal Gut Microbiota Dysbiosis Underlies Olanzapine-Induced Weight Gain

Olanzapine is one of the most effective medicines available for stabilizing schizophrenia spectrum disorders. However, it has been reported to show the greatest propensity for inducing body weight gain and producing metabolic side effects, which cause a great burden in patients with psychiatric disorders. Since the gut microbiota has a profound impact on the initiation and development of metabolic diseases, we conducted a longitudinal study to explore its role in olanzapine-induced obesity and metabolic abnormalities. Female Sprague-Dawley rats were treated with different doses of olanzapine, and metabolic and inflammatory markers were measured. Olanzapine significantly induced body weight gain (up to a 2.1-fold change), which was accompanied by hepatic inflammation and increased plasma triglyceride levels (up to a 2.9-fold change), as well as gut microbiota dysbiosis. Subsequently, fuzzy c-means clustering was used to characterize three clusters of longitudinal trajectories for microbial fluctuations: (i) genera continuing to increase, (ii) genera continuing to decrease, and (iii) genera temporarily changing. Among them, Enterorhabdus (r = 0.38), Parasutterella (r = 0.43), and Prevotellaceae UCG-001 (r = 0.52) positively correlated with body weight gain. In addition, two MetaCyc metabolic pathways were identified as associated with olanzapine-induced body weight gain, including the superpathway of glucose and xylose degradation and the superpathway of l-threonine biosynthesis. In conclusion, we demonstrate that olanzapine can directly alter the gut microbiota and rapidly induce dysbiosis, which is significantly associated with body weight gain. This may suggest gut microbiota targets in future studies on metabolic abnormalities caused by olanzapine. IMPORTANCE Olanzapine is one of the most effective second-generation antipsychotics for stabilizing schizophrenia spectrum disorders. However, olanzapine has multiple drug-induced metabolic side effects, including weight gain. This study provides insight to the gut microbiota target in olanzapine-induced obesity. Specifically, we explored the longitudinal gut microbiota trajectories of female Sprague-Dawley rats undergoing olanzapine treatment. We showed that olanzapine treatment causes a dynamic alteration of gut microbiota diversity. Additionally, we identified three genera, Parasutterella, Enterorhabdus, and Prevotellaceae UCG-001, that may play an important role in olanzapine-induced obesity. In this case, the supply or removal of specific elements of the gut microbiota may represent a promising avenue for treatment of olanzapine-related metabolic side effects.

Thermoneutral housing does not rescue olanzapine-induced trabecular bone loss in C57BL/6J female mice

Antipsychotic drugs are prescribed to a wide range of individuals to treat mental health conditions including schizophrenia. However, antipsychotic drugs cause bone loss and increase fracture risk. We previously found that the atypical antipsychotic (AA) drug risperidone causes bone loss through multiple pharmacological mechanisms, including activation of the sympathetic nervous system in mice treated with clinically relevant doses. However, bone loss was dependent upon housing temperature, which modulates sympathetic activity. Another AA drug, olanzapine, has substantial metabolic side effects, including weight gain and insulin resistance, but it is unknown whether bone and metabolic outcomes of olanzapine are also dependent upon housing temperature in mice. We therefore treated eight week-old female mice with vehicle or olanzapine for four weeks, housed at either room temperature (23 °C) or thermoneutrality (28-30 °C), which has previously been shown to be positive for bone. Olanzapine caused significant trabecular bone loss (-13% BV/TV), likely through increased RANKL-dependent osteoclast resorption, which was not suppressed by thermoneutral housing. Additionally, olanzapine inhibited cortical bone expansion at thermoneutrality, but did not alter cortical bone expansion at room temperature. Olanzapine also increased markers of thermogenesis within brown and inguinal adipose depots independent of housing temperature. Overall, olanzapine causes trabecular bone loss and inhibits the positive effect of thermoneutral housing on bone. Understanding how housing temperature modulates the impact of AA drugs on bone is important for future pre-clinical studies, as well as for the prescription of AA drugs, particularly to older adults and adolescents who are most vulnerable to the effects on bone.

Evolutions of Metabolic Parameters Following Switches of Psychotropic Drugs: A Longitudinal Cohort Study

BACKGROUND

Several psychotropic drugs can induce weight gain and metabolic alterations. The authors compared metabolic evolutions of patients switching versus continuing psychotropic treatments with different risk profiles.

METHODS

Patients either switched from a high- to a medium- (N = 36) or low-risk drug (N = 27), from a medium- to a low-risk drug (N = 71), or to a same-risk drug (N = 61). Controls were kept using either a high- (N = 35), medium- (N = 155), or low-risk drug (N = 47). The evolution over 2 years of weight and metabolic parameters was analyzed using linear mixed-effect models, also examining the influence of polygenic risk scores for body mass index (BMI) or BMI and psychiatric disorders.

STUDY RESULTS

High-, medium-, or low-risk controls gained on average 1.32%, 0.42%, and 0.36% more weight per month than patients switching from or within these risk categories (P < .001, P < .001, and P = .003, respectively). High-to-high or high-to-medium switches resulted in a greater weight increase than switching to lower-risk categories (+0.77% and + 0.39% respectively, P < .001). No difference was found between switching medium-to-medium and medium-to-low (P ≈ 1). Switching high-to-low resulted in 10% weight loss after 2 years, with the greatest loss occurring the first 6 months after the switch. Compared with high-risk controls, lower total cholesterol (-0.27 mmol/l, P = .043) in the high-to-low group, and lower glucose (-0.44 mmol/l, P = .032) and systolic blood pressure (-5.50 mmHg, P = .034) in the low-to-low group were found. Polygenic scores were not associated with weight changes in controls or after switching.

CONCLUSION

Psychotropic switches to a lower- or same-risk drug can attenuate weight gain, with only switching high to low resulting in weight loss.