Venous thromboembolism in recipients of antipsychotics: incidence, mechanisms and management

New role of platelets in schizophrenia: predicting drug response

Background

Elevated platelet count (PLTc) is associated with first-episode schizophrenia and adverse outcomes in individuals with precursory psychosis. However, the impact of antipsychotic medications on PLTc and its association with symptom improvement remain unclear.

Aims

We aimed to investigate changes in PLTc levels following antipsychotic treatment and assess whether PLTc can predict antipsychotic responses and metabolic changes after accounting for other related variables.

Methods

A total of 2985 patients with schizophrenia were randomised into seven groups. Each group received one of seven antipsychotic treatments and was assessed at 2, 4 and 6 weeks. Clinical symptoms were evaluated using the positive and negative syndrome scale (PANSS). Additionally, we measured blood cell counts and metabolic parameters, such as blood lipids. Repeated measures analysis of variance was used to examine the effect of antipsychotics on PLTc changes, while structural equation modelling was used to assess the predictive value of PLTc on PANSS changes.

Results

PLTc significantly increased in patients treated with aripiprazole (F=6.00, p=0.003), ziprasidone (F=7.10, p<0.001) and haloperidol (F=3.59, p=0.029). It exhibited a positive association with white blood cell count and metabolic indicators. Higher baseline PLTc was observed in non-responders, particularly in those defined by the PANSS-negative subscale. In the structural equation model, PLTc, white blood cell count and a latent metabolic variable predicted the rate of change in the PANSS-negative subscale scores. Moreover, higher baseline PLTc was observed in individuals with less metabolic change, although this association was no longer significant after accounting for baseline metabolic values.

Conclusions

Platelet parameters, specifically PLTc, are influenced by antipsychotic treatment and could potentially elevate the risk of venous thromboembolism in patients with schizophrenia. Elevated PLTc levels and associated factors may impede symptom improvement by promoting inflammation. Given PLTc's easy measurement and clinical relevance, it warrants increased attention from psychiatrists.

Trial registration number

ChiCTR-TRC-10000934.

Clinical Characteristics of Asymptomatic Thromboembolism in Psychiatric Inpatients: A Retrospective Study

Purpose

Venous thromboembolism (VTE) poses a significant threat to individuals' health, yet its correlation with mental disorders remains underappreciated. Here, we conducted a retrospective analysis to explore the characteristics of psychiatric patients presenting with VTE.

Methods

We retrospectively analyzed psychiatric inpatients with elevated plasma D-dimer levels at the Mental Health Center, First Affiliated Hospital, Zhejiang University School of Medicine, from January 2014 to January 2022. The inclusion criteria comprised comprehensive demographic and clinical profiles, including laboratory and imaging findings.

Results

A cohort of 33 eligible patients was included, with plasma D-dimer levels ranging from 880 to 10,700 μg/L FEU. Significantly higher D-dimer levels were observed in patients diagnosed with severe mental disorders (SMD), such as schizophrenia and bipolar disorder, compared to those with mild mental disorders (MMD), including depression and anxiety disorders (p = 0.007). Furthermore, individuals receiving antipsychotic medications for less than one year exhibited elevated D-dimer levels compared to those on treatment for over one year (p = 0.005). However, normalization of D-dimer levels did not demonstrate a significant association with psychiatric diagnosis or treatment duration (p > 0.05).

Conclusion

Our findings suggest that patients diagnosed with SMD or those undergoing antipsychotic treatment for less than one year may have elevated D-dimer levels, indicating a potential predisposition to VTE severity. This underscores the importance of recognizing VTE risk in individuals with severe mental disorders and warrants further investigation into the impact of antipsychotic treatment duration on thrombotic risk.

Hypercoagulable state in patients with schizophrenia: different effects of acute and chronic antipsychotic medications

Background

Previous studies reported higher incidences of venous thromboembolism and cardiovascular disease in schizophrenia patients and higher indicators of thrombosis, thrombocyte activation, and platelet dysfunction.

Objectives

To check if first-episode schizophrenia (FES) patients have a hypercoagulable state and determine whether acute and chronic antipsychotics have the same effect on blood coagulation or fibrinolysis-related biomarkers.

Design

Case-control study.

Methods

A total of 81 participants were grouped in FES, chronic schizophrenia (CS), and healthy controls (HCs). In addition to demographic data and clinical characteristics, immunological analyses were performed to measure plasma levels of D-dimer, plasminogen activator inhibitor-1 (PAI-1), soluble P selectin (sP-sel), tissue plasminogen activator (tPA), thrombotic precursor protein (TpP), and von Willebrand's disease factor (vWF).

Results

Compared to HC group, FES patients showed higher PAI-1 (28.61 ng/ml versus 15.69 ng/ml), sP-sel (2.78 ng/ml versus 1.18 ng/ml), and TpP (15.61 µg/ml versus 5.59 µg/ml) along with a higher PAI-1/tPA (3.12 versus 2.00). Acute antipsychotic medication reduced higher PAI-1 (28.61 → 21.99), sP-sel (2.78 → 1.87), tPA (9.59 → 5.83), TpP (15.61 → 10.54), and vWF (383.18 → 291.08) in FES patients. However, plasma sP-sel and vWF in CS patients returned to the pre-treatment levels in FES patients, and PAI-1/tPA significantly decreased compared to FES patients.

Conclusion

These results suggest a hypercoagulable state in FES patients and demonstrate contrast effects of acute and chronic antipsychotics on coagulation or fibrinolysis in schizophrenia patients.

Recognition and management of clozapine adverse effects: A systematic review and qualitative synthesis

OBJECTIVE

Clozapine is substantially underutilized in most countries and clinician factors including lack of knowledge and concerns about adverse drug effects (ADEs) contribute strongly to treatment reluctance. The aim of this systematic review was to provide clinicians with a comprehensive information source regarding clozapine ADEs.

METHODS

PubMed and Embase databases were searched for English language reviews concerned with clozapine ADEs; publications identified by the automated search were manually searched for additional relevant citations. Following exclusion of redundant and irrelevant reports, pertinent information was summarized in evidence tables corresponding to each of six major ADE domains; two authors reviewed all citations for each ADE domain and summarized their content by consensus in the corresponding evidence table. This study was conducted in accordance with PRISMA principles.

RESULTS

Primary and secondary searches identified a total of 305 unique reports, of which 152 were included in the qualitative synthesis. Most clozapine ADEs emerge within 3 months, and almost all appear within 6 months, after initiation. Notable exceptions are weight gain, diabetic ketoacidosis (DKA), severe clozapine-induced gastrointestinal hypomotility (CIGH), clozapine-induced cardiomyopathy (CICM), seizures, and clozapine-induced neutropenia (CIN). Most clozapine ADEs subside gradually or respond to dose reduction; those that prompt discontinuation generally do not preclude rechallenge. Rechallenge is generally inadvisable for clozapine-induced myocarditis (CIM), CICM, and clozapine-induced agranulocytosis (CIA). Clozapine plasma levels >600-1000 μg/L appear more likely to cause certain ADEs (e.g., seizures) and, although there is no clear toxicity threshold, risk/benefit ratios are generally unfavorable above 1000 μg/L.

CONCLUSION

Clozapine ADEs rarely require discontinuation.

Deep vein thrombosis on the fourth day of risperidone therapy

Deep vein thrombosis has been recognised as a complication of antipsychotic treatment and is reported to be more common with atypical antipsychotics. Risperidone is a second-generation atypical antipsychotic and there have been case reports of risperidone-associated deep vein thrombosis, most of them reporting the complication from 2 weeks to a few months of initiation of therapy. Here, we are reporting a case of deep vein thrombosis in a male patient in his early forties with paranoid schizophrenia, which presented on the fourth day of starting risperidone therapy. This case is being reported to highlight the fact that deep vein thrombosis can occur as early as fourth day of initiation of risperidone therapy, that too at a low dose (2 mg/day). The case also emphasises the importance of monitoring these patients for this rare but potentially serious adverse effect from the first day itself after initiation of a new antipsychotic.

Clozapine-induced pulmonary embolism in a patient with minimal pre-existing risk factors

OBJECTIVES

Although the risk of antipsychotic-induced venous thromboembolism (VTE) has been definitively established, guidelines recommending prophylactic anticoagulation do not yet exist. Several algorithms have been proposed that suggest possible prophylaxis with an anticoagulant medication on the basis of pre-existing VTE risk factors. We present a case of antipsychotic-induced VTE despite the patient's low-risk status so that practitioners may better understand which factors may or may not constitute a major risk in this population when making a determination about prophylactic anticoagulation.

CASE SUMMARY

We present a patient case of a 56-year-old man with schizoaffective disorder who was treated with clozapine at an inpatient psychiatric unit. Although he would be classified as low risk for VTE on the basis of the proposed algorithms, he experienced a pulmonary embolism by day 17 of treatment and required transfer to a medical unit. This patient displayed sensitivity to other adverse effects associated with clozapine during his treatment course, including tachycardia, sialorrhea, enuresis, and bowel obstruction.

PRACTICE IMPLICATIONS

Many of the known risk factors for antipsychotic-induced VTE were not present in this patient, including immobility, hyperprolactinemia, and coagulation abnormalities. The recent initiation of clozapine and obesity seem to be the only identified risk factors, although malignancy and abnormal antiphospholipid antibody levels were not able to be ruled out. It is difficult to determine if this patient experienced a VTE owing to a relatively high degree of sensitivity to clozapine, as evidenced by the myriad of other adverse effects that he experienced. This case highlights the need to determine true antipsychotic-induced VTE risk factors, including evaluation of comorbid adverse effects that occur in addition to the VTE. This information will help to guide future decision-making regarding the risk versus benefit of providing prophylactic anticoagulation for patients during initiation of antipsychotic treatment.

Atypical antipsychotic clozapine binds fibrinogen and affects fibrin formation

Clozapine is an atypical antipsychotic used for the treatment of schizophrenia. The prescribed target daily doses may reach 900 mg. Literature studies report a connection between clozapine usage and thrombosis development. Our in vitro study aimed to provide insight into molecular bases of this observation, investigating clozapine binding to fibrinogen, the main plasma protein involved in hemostasis. Fibrinogen/clozapine interaction was confirmed by protein fluorescence quenching, with an affinity constant of 1.7 × 10⁵ M^-1. Direct interactions did not affect the structure of fibrinogen, nor fibrinogen melting temperature. Clozapine binding affected fibrin formation by reducing coagulation speed and thickness of fibrin fibers suggesting that in the presence of clozapine, fibrinogen may acquire thrombogenic characteristics. Although no difference in fibrin gel porosity was detected, other factors present in the blood may act synergistically with altered fibrin formation to modify fibrin clot, thus increasing the risk for development of thrombosis in patients on clozapine treatment. ORAC and HORAC assays showed that clozapine reduced free radical-induced oxidation of fibrinogen. All observed effects of clozapine on fibrinogen are dose-dependent, with the effect on fibrin formation being more pronounced.

Evidence-based guidelines for the pharmacological treatment of schizophrenia: Updated recommendations from the British Association for Psychopharmacology

These updated guidelines from the British Association for Psychopharmacology replace the original version published in 2011. They address the scope and targets of pharmacological treatment for schizophrenia. A consensus meeting was held in 2017, involving experts in schizophrenia and its treatment. They were asked to review key areas and consider the strength of the evidence on the risk-benefit balance of pharmacological interventions and the clinical implications, with an emphasis on meta-analyses, systematic reviews and randomised controlled trials where available, plus updates on current clinical practice. The guidelines cover the pharmacological management and treatment of schizophrenia across the various stages of the illness, including first-episode, relapse prevention, and illness that has proved refractory to standard treatment. It is hoped that the practice recommendations presented will support clinical decision making for practitioners, serve as a source of information for patients and carers, and inform quality improvement.

Safety of antipsychotics for the treatment of schizophrenia: a focus on the adverse effects of clozapine

Clozapine, a dibenzodiazepine developed in 1961, is a multireceptorial atypical antipsychotic approved for the treatment of resistant schizophrenia. Since its introduction, it has remained the drug of choice in treatment-resistant schizophrenia, despite a wide range of adverse effects, as it is a very effective drug in everyday clinical practice. However, clozapine is not considered as a top-of-the-line treatment because it may often be difficult for some patients to tolerate as some adverse effects can be particularly bothersome (i.e. sedation, weight gain, sialorrhea etc.) and it has some other potentially dangerous and life-threatening side effects (i.e. myocarditis, seizures, agranulocytosis or granulocytopenia, gastrointestinal hypomotility etc.). As poor treatment adherence in patients with resistant schizophrenia may increase the risk of a psychotic relapse, which may further lead to impaired social and cognitive functioning, psychiatric hospitalizations and increased treatment costs, clozapine adverse effects are a common reason for discontinuing this medication. Therefore, every effort should be made to monitor and minimize these adverse effects in order to improve their early detection and management. The aim of this paper is to briefly summarize and provide an update on major clozapine adverse effects, especially focusing on those that are severe and potentially life threatening, even if most of the latter are relatively uncommon.

Venous thromboembolism following initiation of atypical antipsychotics in two geriatric patients

Background

Although not formally highlighted as a risk factor in current practice guidelines, several observational studies have reported a possible association between antipsychotic use and development of venous thromboembolism (VTE). However, it is unclear to what extent the risk is elevated.

Case Report

Described are 2 cases of VTE following recent initiation of second-generation antipsychotics in elderly patients. Ms A was a 65-year-old woman with newly diagnosed bipolar I disorder who was hospitalized for acute mania and psychosis. She was treated with risperidone along with traditional mood stabilizers and developed a pulmonary embolism shortly after treatment initiation. Ms B was a 77-year-old woman with newly diagnosed bipolar I disorder who was hospitalized for depression and psychosis. She was treated with quetiapine and electroconvulsive therapy and developed a pulmonary embolism and deep vein thrombosis within 2 months of starting treatment. Risk assessment tools were not able to definitively predict the VTEs that developed in our patients.

Conclusion

The association between antipsychotic medication and VTE has shown the highest risk with atypical antipsychotics, high dosages, and initiation within the past 3 months. Risk assessment tools may assist in assessing the risk of VTE in patients on antipsychotic therapy, although patients who are deemed by these tools to have minimal risk can still develop a VTE. Discussing VTE risk with patients when considering antipsychotic usage may help clinicians and patients safely determine the most appropriate treatment for their psychiatric illnesses while mitigating potential adverse effects.

Venous Thromboembolism During Treatment with Antipsychotics: A Review of Current Evidence

This article summarises the current evidence on the risk of venous thromboembolism (VTE) with the use of antipsychotics. An increasing number of observational studies indicate an elevated risk of VTE in antipsychotic drug users. Although the use of certain antipsychotics has been associated with VTE, current data can neither conclusively verify differences in occurrence rates of VTE between first- and second-generation antipsychotics or between individual compounds, nor identify which antipsychotic drugs have the lowest risk of VTE. The biological mechanisms involved in the pathogenesis of this adverse drug reaction are still to be clarified but hypotheses such as drug-induced sedation, obesity, increased levels of antiphospholipid antibodies, enhanced platelet aggregation, hyperhomocysteinaemia and hyperprolactinaemia have been suggested. Risk factors associated with the underlying psychiatric disorder may at least partly explain the increased risk. Physicians should be aware of this potentially serious and even sometimes fatal adverse drug reaction and should consider discontinuing or switching the antipsychotic treatment in patients experiencing a VTE. Even though supporting evidence is limited, prophylactic antithrombotic treatment should be considered in risk situations for VTE.

Myocardial infarction risk and antipsychotics use revisited: a meta-analysis of 10 observational studies

OBJECTIVE

Associations between antipsychotic agent (AP) use and myocardial infarction (MI) risk have been inconsistent and remain controversial. We therefore conducted a meta-analysis of observational studies to address this knowledge gap.

METHOD

Detailed electronic database searches were performed to identify reports of observational studies that evaluated the association between AP use and the risk of MI. Pooled odds ratios (ORs) were calculated using random or fixed-effects models.

RESULTS

In total, four case-control studies, two case-crossover studies, one case-case time control study, three cohort studies, and one self-controlled case series were included. The pooled OR (95% confidence interval (CI)) between any AP use and MI risk was 1.55 (1.33-1.79) compared with non-use: 1.39 (1.06-1.82) for atypical AP use and 1.57 (1.29-1.91) for typical AP use. Subgroup analyses indicated that male gender, schizophrenia diagnosis, and AP exposure periods ≤60 days were associated with higher risk of MI.

CONCLUSION

Current evidence, based on 10 observational studies, suggested that AP use might be a potential risk factor of MI. However, we cannot conclude at this time due to significant heterogeneity among studies. We suggest that, instead of not using APs in fear of MI risk, careful cardiovascular monitoring before and during AP treatment in high-risk patients is needed. Additional high-quality prospective studies are required to evaluate the association between APs and the risk of MI.

Use of antipsychotics and risk of venous thromboembolism in postmenopausal women

Despite continued uncertainty of venous thromboembolism (VTE) caused from antipsychotic agents, this safety issue has not been examined in postmenopausal women, a population with high usages of antipsychotics and at high risk for VTE. We assessed whether antipsychotic use was associated with an increased VTE risk in women after menopause. We conducted a nested case-control study of all Taiwanese women aged ≥ 50 years (n = 316,132) using a nationwide healthcare claims database between 2000 and 2011. All newly diagnosed VTE patients treated with an anticoagulant or thrombectomy surgery were identified as cases (n = 2,520) and individually matched to select controls (n = 24,223) by cohort entry date, age, cancer diagnosis and major surgery procedure. The odds ratios (ORs) and 95 % confidence interval (CI) of VTE associated with antipsychotics were estimated by multivariate conditional logistic regressions. Current use of antipsychotics was associated with a 1.90-fold (95 % CI = 1.64–2.19) increased VTE risk compared with nonuse in postmenopausal women. The VTE risk existed in a dose-dependent fashion (test for trend, p<0.001), with a more than quadrupled risk for high-dose antipsychotics (adjusted OR = 4.60; 95 % CI = 2.88–7.33). Current parenteral administration of antipsychotics also led to a 3.46-fold increased risk (95 % CI = 2.39–5.00). Conversely, there was no increased VTE risk when antipsychotics were discontinued for > 30 days. In conclusion, current use of antipsychotics is significantly associated with a dose-dependent increased risk of VTE in postmenopausal women, especially for those currently taking high-dose or receiving parenteral antipsychotics.

Cardiovascular Disease in Clozapine-Treated Patients: Evidence, Mechanisms and Management

Myocarditis occurs in about 3% of those initiated on clozapine but monitoring reduces the risk of serious outcome. Cardiomyopathy may develop after myocarditis, or from prolonged tachycardia. Monitoring using echocardiography is not deemed cost effective. Tachycardia, orthostatic hypotension and reduced heart rate variability are a group of clozapine-related adverse effects associated with autonomic dysfunction and may have serious consequences in the long term. Elevated heart rate and poor heart rate variability can be treated with a β-blocker or a non-dihydropyridine calcium channel blocker, while orthostatic hypotension can be alleviated by increased fluid intake and abdominal binding, but may require pharmacological intervention. Adequate correction for heart rate may show that clozapine does not prolong the QT interval. Other cardiovascular effects, pulmonary embolism, metabolic syndrome, sudden cardiac death and particularly the excessive mortality from cardiovascular disease events may be more strongly associated with the combination of mental illness, lifestyle factors and poor treatment of cardiovascular disease and its risk factors than with clozapine treatment. In view of the efficacy of clozapine and the evidence of reduced mortality relative to other antipsychotics, clozapine should be prescribed when indicated and recipients should be enrolled in lifestyle programmes to increase exercise and improve diet, and referred for diagnosis and treatment of cardiovascular disease and its risk factors.

Antipsychotic Use Among Adult Outpatients and Venous Thromboembolic Disease: A Retrospective Cohort Study

BACKGROUND

Treatment with antipsychotic (AP) agents is associated with incident thromboembolic events. However, the underpinnings of this association remain unknown. We sought to evaluate the effect of AP agents-categorized by their metabolic/sedative and hyperprolactinemia adverse effect profile-on the risk of venous thromboembolic disease during long-term follow-up.

METHODS

A retrospective cohort study of adult patients initiating AP treatment for the first time was conducted. Primary outcome was defined as the time to venous thromboembolism (VTE) (either deep venous thrombosis or acute pulmonary embolism). Antipsychotic agents were categorized by their risk (high vs low) of either drug-induced (a) sedation/metabolic adverse event or (b) hyperprolactinemia. We used a propensity score-adjusted Cox proportional hazards model to control for confounding.

FINDINGS

One thousand eight patients (mean age, 72.4 y) were followed for a median of 36 months. Incident VTE occurred in 6.25% of patients, corresponding to an incidence rate of 184 cases per 10,000 person-years. We found no difference in the hazard of VTE during follow-up between high- and low-risk groups (hazard ratio, 1.23 [95% confidence interval, 0.74-2.04] for drug-induced sedation/metabolic adverse event risk categories, and hazard ratio 0.81 [95% confidence interval, 0.50-1.35] for high versus low hyperprolactinemia risk).

CONCLUSIONS

These results suggest that the risk of thromboembolic events in older adults who started AP treatment for the first time does not seem to be related to these drugs' risk of either sedation/metabolic adverse events or hyperprolactinemia. However, VTE remains a common problem in this subgroup of patients.

Antidepressants, Depression, and Venous Thromboembolism Risk: Large Prospective Study of UK Women

BACKGROUND

Some investigators have reported an excess risk of venous thromboembolism (VTE) associated with depression and with use of antidepressant drugs. We explored these associations in a large prospective study of UK women.

METHODS AND RESULTS

The Million Women Study recruited 1.3 million women through the National Health Service Breast Screening Programme in England and Scotland. Three years after recruitment, women were sent a second questionnaire that enquired about depression and regular use of medications in the previous 4 weeks. The present analysis included those who responded and did not have prior VTE, cancer, or recent surgery. Follow-up for VTE was through linkage to routinely collected National Health Service statistics. Cox regression analyses yielded adjusted hazard ratios and 95% CIs. A total of 734 092 women (mean age 59.9 years) were included in the analysis; 6.9% reported use of antidepressants, 2.7% reported use of other psychotropic drugs, and 1.8% reported being treated for depression or anxiety but not use of psychotropic drugs. During follow-up for an average of 7.3 years, 3922 women were hospitalized for and/or died from VTE. Women who reported antidepressant use had a significantly higher risk of VTE than women who reported neither depression nor use of psychotropic drugs (hazard ratio, 1.39; 95% CI, 1.23-1.56). VTE risk was not significantly increased in women who reported being treated for depression or anxiety but no use of antidepressants or other psychotropic drugs (hazard ratio, 1.19; 95% CI, 0.95-1.49).

CONCLUSIONS

Use of antidepressants is common in UK women and is associated with an increased risk of VTE.

Medical Complications of Psychiatric Treatment: An Update

Psychiatric medications are used commonly in hospitalized patients and are particularly indicated in patients who are critically ill to manage many conditions. Due to their many indications in the intensive care unit (ICU), psychiatric medications should be closely monitored in these medically compromised patients for adverse reactions and medical complications because they may affect essentially all organ systems. These range from life-threatening reactions to other less significant effects, such as sedation, to other detrimental complications, such as pancreatitis. Knowledge of psychopharmacology as well as the diagnosis and treatment of these complications is imperative in treating patients in the ICU.

Theoretical and practical issues related to the management of severe and refractory psychotic illness complicated by pulmonary embolism

Pulmonary embolism (PE) is a potentially fatal condition. We describe the educative case of a young adult male, with a longstanding history of schizophrenia, who was receiving anticoagulant treatment because of repeated episodes of PE in the past. He presented with severe exacerbation of psychosis and did not respond to oral and parenteral antipsychotic medication during inpatient treatment. He was taken up for electroconvulsive therapy (ECT) and received a single ECT uneventfully. The ECT course had to be interrupted because of the unexpected development of a 4-day febrile illness, after which he experienced sudden onset breathlessness, which was diagnosed as acute-on-chronic PE. After the crisis resolved with 4 days of intensive care, he was managed with clozapine. We discuss concerns associated with the psychiatric management of patients with PE; special issues include the use of restraints, parenteral antipsychotic medications, anticoagulants, and ECT.

Antipsychotic drug exposure and risk of pulmonary embolism: a population-based, nested case-control study

BACKGROUND

Only three observational studies investigated whether exposure to antipsychotics is associated with an increased risk of pulmonary embolism, with conflicting results. This study was therefore carried out to establish the risk of pulmonary embolism associated with antipsychotic drugs, and to ascertain the risk associated with first- and second-generation antipsychotic drugs, and with exposure to individual drugs.

METHODS

We identified 84,253 adult individuals who began antipsychotic treatment in a large Italian health care system. Cases were all cohort members who were hospitalized for non-fatal or fatal pulmonary embolism during follow-up. Up to 20 controls for each case were extracted from the study cohort using incidence density sampling and matched by age at cohort entry and gender. Each individual was classified as current, recent or past antipsychotic user. The occurrence non-fatal or fatal pulmonary embolism was the outcome of interest.

RESULTS

Compared to past use, current antipsychotic use more than double the risk of pulmonary embolism (odds ratio 2.31, 95% confidence interval 1.16 to 4.59), while recent use did not increase the risk. Both conventional and atypical antipsychotic exposure was associated with an increase in risk, and the concomitant use of both classes increased the risk of four times (odds ratio 4.21, 95% confidence interval 1.53 to 11.59).

CONCLUSIONS

Adding the results of this case-control study to a recent meta-analysis of three observational studies substantially changed the overall estimate, which now indicates that antipsychotic exposure significantly increases the risk of pulmonary embolism.

Clozapine-Induced Late Agranulocytosis and Severe Neutropenia Complicated with Streptococcus pneumonia, Venous Thromboembolism, and Allergic Vasculitis in Treatment-Resistant Female Psychosis

Clozapine is a second-generation antipsychotic agent from the benzodiazepine group indicated for treatment-resistant schizophrenia and other psychotic conditions. Using clozapine earlier on once a case appears to be refractory limits both social and personal morbidity of chronic psychosis. However treatment with second-generation antipsychotics is often complicated by adverse effects. We present a case of a 33-year-old Caucasian woman with a 25-year history of refractory psychotic mania after switching to a 2-year clozapine therapy. She presented clozapine-induced absolute neutropenia, agranulocytosis, which were complicated by Streptococcus pneumonia and sepsis. Clozapine-induced thromboembolism of the common femoral and right proximal iliac vein, as well as allergic vasculitis, was diagnosed. She achieved full remission on granulocyte-colony stimulating factor and specific antibiotic treatment. Early detection of severe clozapine-induced absolute neutropenia and agranulocytosis enabled the effective treatment of two among its most severe complications. Additional evidence to the previously reported possible causal relation between clozapine and venous thromboembolism is offered. Finally, clozapine-induced allergic vasculitis is confirmed as a late adverse effect of clozapine therapy.

Transcriptome alterations of mitochondrial and coagulation function in schizophrenia by cortical sequencing analysis

Background

Transcriptome sequencing of brain samples provides detailed enrichment analysis of differential expression and genetic interactions for evaluation of mitochondrial and coagulation function of schizophrenia. It is implicated that schizophrenia genetic and protein interactions may give rise to biological dysfunction of energy metabolism and hemostasis. These findings may explain the biological mechanisms responsible for negative and withdraw symptoms of schizophrenia and antipsychotic-induced venous thromboembolism.

We conducted a comparison of schizophrenic candidate genes from literature reviews and constructed the schizophrenia-mediator network (SCZMN) which consists of schizophrenic candidate genes and associated mediator genes by applying differential expression analysis to BA22 RNA-Seq brain data. The network was searched against pathway databases such as PID, Reactome, HumanCyc, and Cell-Map. The candidate complexes were identified by MCL clustering using CORUM for potential pathogenesis of schizophrenia.

Results

Published BA22 RNA-Seq brain data of 9 schizophrenic patients and 9 controls samples were analyzed. The differentially expressed genes in the BA22 brain samples of schizophrenia are proposed as schizophrenia candidate marker genes (SCZCGs). The genetic interactions between mitochondrial genes and many under-expressed SCZCGs indicate the genetic predisposition of mitochondria dysfunction in schizophrenia. The biological functions of SCZCGs, as listed in the Pathway Interaction Database (PID), indicate that these genes have roles in DNA binding transcription factor, signal and cancer-related pathways, coagulation and cell cycle regulation and differentiation pathways.

In the query-query protein-protein interaction (QQPPI) network of SCZCGs, TP53, PRKACA, STAT3 and SP1 were identified as the central "hub" genes. Mitochondrial function was modulated by dopamine inhibition of respiratory complex I activity. The genetic interaction between mitochondria function and schizophrenia may be revealed by DRD2 linked to NDUFS7 through protein-protein interactions of FLNA and ARRB2.

The biological mechanism of signaling pathway of coagulation cascade was illustrated by the PPI network of the SCZCGs and the coagulation-associated genes. The relationship between antipsychotic target genes (DRD2/3 and HTR2A) and coagulation factor genes (F3, F7 and F10) appeared to cascade the following hemostatic process implicating the bottleneck of coagulation genetic network by the bridging of actin-binding protein (FLNA).

Conclusions

It is implicated that the energy metabolism and hemostatic process have important roles in the pathogenesis for schizophrenia. The cross-talk of genetic interaction by these co-expressed genes and reached candidate genes may address the key network in disease pathology. The accuracy of candidate genes evaluated from different quantification tools could be improved by crosstalk analysis of overlapping genes in genetic networks.

Antipsychotic drug exposure and risk of venous thromboembolism: a systematic review and meta-analysis of observational studies

BACKGROUND

Venous thromboembolism (VTE) is a serious disorder that may be complicated by pulmonary embolism (PE). Case reports and observational studies published in the early 1950s suggested that antipsychotic (AP) drugs may represent a risk factor, while observational studies conducted in the last 3 decades have provided conflicting results.

OBJECTIVE

The aim was to investigate whether AP drugs increase the risk of VTE and PE, and to ascertain the risk associated with first- and second-generation AP drugs and with exposure to individual drugs.

DATA SOURCE

Relevant studies were located by searching MEDLINE, PubMed, EMBASE, PsychINFO, CINAHL and Scopus up to March 2013. Reference lists of relevant papers and previous review articles were hand searched for other relevant studies.

STUDY SELECTION

Based on the titles and abstracts of 1,386 citations, we identified 30 potentially relevant studies. Of these, 17 studies were eligible for inclusion and were included in the meta-analysis.

MAIN OUTCOMES AND MEASURES

The primary outcome measure of this meta-analysis was the occurrence of VTE or PE in individuals exposed to AP drugs in comparison with individuals unexposed or with past exposure to AP drugs.

RESULTS

Antipsychotic exposure was associated with a significant increase in risk of developing VTE [odds ratio (OR) 1.54, 95% confidence interval (CI) 1.28-1.86, 11 studies]. Exposure to APs did not significantly increase the risk of PE (OR 4.90, 95% CI 0.77-30.98, three studies), but the overall estimate was highly heterogeneous and the CI included the possibility of substantial harm. Random-effects meta-analysis on the risk of VTE associated with exposure to first- (OR 1.74, 95% CI 1.28-2.37, six studies) and second-generation (OR 2.07, 95% CI 1.74-2.52, five studies) APs revealed an increased risk. Only a few studies provided data on individual drugs, and estimates of effect were very uncertain.

CONCLUSIONS

Antipsychotic exposure in unselected patient populations may be associated with a 50% increase in the risk of developing VTE. However, between-study heterogeneity limits the confidence in this estimate. This increased risk similarly applies to first- and second-generation AP drugs.

Quantifying the role of adverse events in the mortality difference between first and second-generation antipsychotics in older adults: systematic review and meta-synthesis

BACKGROUND

Observational studies have reported higher mortality among older adults treated with first-generation antipsychotics (FGAs) versus second-generation antipsychotics (SGAs). A few studies examined risk for medical events, including stroke, ventricular arrhythmia, venous thromboembolism, myocardial infarction, pneumonia, and hip fracture.

OBJECTIVES

1) Review robust epidemiologic evidence comparing mortality and medical event risk between FGAs and SGAs in older adults; 2) Quantify how much these medical events explain the observed mortality difference between FGAs and SGAs.

DATA SOURCES

Pubmed and Science Citation Index.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

Studies of antipsychotic users that: 1) evaluated mortality or medical events specified above; 2) restricted to populations with a mean age of 65 years or older 3) compared FGAs to SGAs, or both to a non-user group; (4) employed a "new user" design; (5) adjusted for confounders assessed prior to antipsychotic initiation; (6) and did not require survival after antipsychotic initiation. A separate search was performed for mortality estimates associated with the specified medical events.

STUDY APPRAISAL AND SYNTHESIS METHODS

For each medical event, we used a non-parametric model to estimate lower and upper bounds for the proportion of the mortality difference-comparing FGAs to SGAs-mediated by their difference in risk for the medical event.

RESULTS

We provide a brief, updated summary of the included studies and the biological plausibility of these mechanisms. Of the 1122 unique citations retrieved, we reviewed 20 observational cohort studies that reported 28 associations. We identified hip fracture, stroke, myocardial infarction, and ventricular arrhythmias as potential intermediaries on the causal pathway from antipsychotic type to death. However, these events did not appear to explain the entire mortality difference.

CONCLUSIONS

The current literature suggests that hip fracture, stroke, myocardial infarction, and ventricular arrhythmias partially explain the mortality difference between SGAs and FGAs.

Clinically relevant interactions between newer antidepressants and second-generation antipsychotics

INTRODUCTION

Combinations of newer antidepressants and second-generation antipsychotics (SGAs) are frequently used by clinicians. Pharmacokinetic drug interaction (PK DI) and poorly understood pharmacodynamic (PD) drug interaction (PD DI) can occur between them.

AREAS COVERED

This paper comprehensively reviews PD DI and PK DI studies.

EXPERT OPINION

More PK DI studies are needed to better establish dose correction factors after adding fluoxetine and paroxetine to aripiprazole, iloperidone and risperidone. Further PK DI studies and case reports are also needed to better establish the need for dose correction factors after adding i) fluoxetine to clozapine, lurasidone, quetiapine and olanzapine; ii) paroxetine to olanzapine; iii) fluvoxamine to asenapine, aripiprazole, iloperidone, lurasidone, olanzapine, quetiapine and risperidone; iv) high sertraline doses to aripiprazole, clozapine, iloperidone and risperidone: v) bupropion and duloxetine to aripiprazole, clozapine, iloperidone and risperidone; and vi) asenapine to paroxetine and venlafaxine. Possible beneficial PD DI effects occur after adding SGAs to newer antidepressants for treatment-resistant major depressive and obsessive-compulsive disorders. The lack of studies combining newer antidepressants and SGAs in psychotic depression is worrisome. PD DIs between newer antidepressants and SGAs may be more likely for mirtazapine and bupropion. Adding selective serotonin reuptake inhibitors and SGAs may increase QTc interval and may very rarely contribute to torsades de pointes.

Pulmonary thromboembolism due to paliperidone: report of 2 cases

Venous thromboembolism (VTE) is serious medical condition, which might be caused by psychotropic medications. Previously, antipsychotic-induced VTE due to olanzapine, risperidone, clozapine, and amisulpiride was reported. In this report, we present 2 cases of paliperidone-induced VTE.

Thrombotic risk in patients with immune thrombocytopenia and its association with antiphospholipid antibodies

Patients with immune thrombocytopenia (ITP) paradoxically have an increased risk of thrombosis. The presence of antiphospholipid antibodies (aPL) has been observed in a substantial proportion of ITP patients, but its clinical significance remains to be established. This study retrospectively investigated the prevalence and clinical significance of aPL in ITP patients and assessed the risk factors for thrombosis. One hundred and sixty-five subjects with ITP were included in the study and followed for a mean period of 63·4 months. Sixty-nine (41·6%) patients were positive for aPL at diagnosis, and their clinical characteristics and course of ITP were not different from those of aPL-negative patients. Twenty-one (12·7%) patients developed a thrombotic event during follow-up and the cumulative incidence rate ratio of aPL-positive to aPL-negative patients for thromboembolism was 3·15 [95% confidence interval (CI) 1·21-8·17] after adjusting for confounding factors. Lupus anticoagulant and hypertension were identified by Cox regression analysis as independent risk factors for thrombosis [hazard ratio (HR) 4·1, 95% CI 1·4-11·9, P = 0·009 and HR 5·6, 95% CI 1·9-15·8, P = 0·001, respectively]. Our results showed that a substantial proportion of ITP patients were aPL-positive, and that lupus anticoagulant and hypertension were independent risk factors for thrombosis. Detection of aPL can provide useful information for identifying patients at high-risk for developing thrombosis.

Pulmonary embolism related to amisulpride treatment: a case report

Venous thromboembolism has been associated with antipsychotic drugs, but the underlying mechanisms are largely unknown. Hypotheses that have been made include body weight gain, sedation, enhanced platelet aggregation, increased levels of antiphospholipid antibodies, hyperhomocysteinemia, whereas hyperprolactinemia has recently attracted attention as a potential contributing factor. The highest risk has been demonstrated for clozapine, olanzapine, and low-potency first-generation antipsychotics; however, presently there is no data for amisulpride. In the present paper we describe a case of pulmonary embolism in a female bipolar patient, receiving treatment with amisulpride, aripiprazole, and paroxetine. Although a contribution of aripiprazole and paroxetine cannot completely be ruled out, the most probable factor underlying the thromboembolic event seems to be hyperprolactinemia, which was caused by amisulpride treatment. Increased plasma levels of prolactin should probably be taken into account during the monitoring of antipsychotic treatment as well as in future research concerning venous thromboembolism in psychiatric settings.