Clozapine-associated myocarditis: a review of 116 cases of suspected myocarditis associated with the use of clozapine in Australia during 1993-2003

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.

Clozapine-Induced Cardiovascular Side Effects and Autonomic Dysfunction: A Systematic Review

Background: Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and has minimal risk for extrapyramidal symptoms. Therapeutic benefits, however, are accompanied by a myriad of cardiometabolic side-effects. The specific reasons for clozapine's high propensity to cause adverse cardiometabolic events remain unknown, but it is believed that autonomic dysfunction may play a role in many of these.

Objective: This systematic review summarizes the literature on autonomic dysfunction and related cardiovascular side effects associated with clozapine treatment.

Method: A search of the EMBASE, MEDLINE, and EBM Cochrane databases was conducted using the search terms antipsychotic agents, antipsychotic drug^*, antipsychotic^*, schizophrenia, schizophren^*, psychos^*, psychotic^*, mental ill^*, mental disorder^*, neuroleptic^*, cardiovascular^*, cardiovascular diseases, clozapine^*, clozaril^*, autonomic^*, sympathetic^*, catecholamine^*, norepinephrine, noradrenaline, epinephrine, adrenaline.

Results: The search yielded 37 studies that were reviewed, of which only 16 studies have used interventions to manage cardiovascular side effects. Side effects reported in the studies include myocarditis, orthostatic hypotension and tachycardia. These were attributed to sympathetic hyperactivity, decreased vagal contribution, blockade of cholinergic and adrenergic receptors, reduced heart rate variability and elevated catecholamines with clozapine use. Autonomic neuropathy was identified by monitoring blood pressure and heart rate changes in response to stimuli and by spectral analysis of heart rate variability. Metoprolol, lorazepam, atenolol, propranolol, amlodipine, vasopressin and norepinephrine infusion were used to treat tachycardia and fluctuations in blood pressure, yet results were limited to case reports.

Conclusion: The results indicate there is a lack of clinical studies investigating autonomic dysfunction and a limited use of interventions to manage cardiovascular side effects associated with clozapine. As there is often no alternative treatment for refractory schizophrenia, the current review highlights the need for better designed studies, use of autonomic tests for prevention of cardiovascular disease and development of novel interventions for clozapine-induced side effects.

Hearts and Minds: Real-Life Cardiotoxicity With Clozapine in Psychosis

BACKGROUND

Schizophrenia has a 1% prevalence in the population; 30% of these patients are treatment refractory. Clozapine is the only drug licensed to treat treatment refractory psychosis, but concerns about potential adverse effects result in only a proportion of eligible patients being treated. Although a well-documented neutropenia risk is mitigated by routine blood testing, cardiac toxicity is a commonly cited reason to discontinue clozapine treatment. However, there is little data on the real-life cardiac outcomes in those receiving clozapine treatment.

METHODS

Retrospective review of electrocardiogram, echocardiogram, and clinical outcomes in 39 inpatients with treatment-refractory schizophrenia, treated with clozapine and other antipsychotic medication, referred for cardiology opinion.

RESULTS

Commonest reasons for referral were development of left ventricular (LV) impairment or sinus tachycardia with normal LV function. Patients were reviewed by a range of cardiologists, receiving varied interventions.Median LV ejection fraction in the clozapine group was normal (52%). Serial echocardiograms demonstrated that clozapine-treated patients with LV impairment had no change in LV ejection fraction over a 4-month follow-up. Left ventricular ejection fraction did not differ between patients treated with clozapine and other antipsychotics. However, over an 11-year follow-up period, 48% of patients had discontinued clozapine treatment.

CONCLUSIONS

This naturalistic study demonstrates that clozapine is not associated with significant cardiac mortality or morbidity. There is a real need for multidisciplinary working between specialist cardiologists and psychiatrists caring for these complex patients to facilitate optimal long-term physical and mental health outcomes.

Management of serious cardiac adverse effects of antipsychotic medications

The use of antipsychotic medications has now expanded to multiple mental health conditions beyond schizophrenia. This has increased the overall population exposure to these medications, which have been associated with both metabolic changes and adverse cardiovascular effects. QTc prolongation, torsades de pointes, sudden cardiac death, myocarditis, and cardiomyopathy are all very real concerns that clinicians face on a regular basis. One must take these risks into consideration when selecting antipsychotic therapy and also when determining whether therapeutic changes and adjustments are necessary. This review examines a number of cardiac-associated concerns, the role that antipsychotics may play in contributing to these adverse events, and suggested management interventions.

Efficacy and Tolerability of Clozapine versus Quetiapine in Treatment-resistant Schizophrenia

OBJECTIVES

To compare the efficacy and tolerability of clozapine and quetiapine in patients with treatment-resistant schizophrenia (TRS).

PATIENTS AND METHODS

In this prospective, randomized, open label study of 14 weeks, 53 patients with schizophrenia diagnosed as per ICD-10 and fulfilling the modified version of Conley and Kelly's criteria of TRS were randomly assigned to receive clozapine or quetiapine as per a computer-generated random table. After 2-weeks of dose-titration phase, doses were fixed at minimum therapeutic dose and subsequently adjusted according to the clinical improvement. All patients received dosage of respective drug in therapeutic range. 13 patients were lost to follow up. Treatment efficacy and side effects were evaluated with standardized rating scales.

RESULTS

Clozapine group (reduction in total score: mean=14.45, SD=10.39) had significantly greater reductions (P=0.004; CI=3.541-17.059) in the Positive and Negative Syndrome Scale (PANSS) total score, PANSS positive subscale and PANSS general psychopathology subscale at 14 weeks in comparison to the quetiapine group (reduction in total score: mean=4.15, SD=10.71). Significant reduction in PANSS negative subscale was seen with both drugs but no significant difference was present between the two drugs. At 14 weeks, 30% patients in clozapine group and 15% patients in quetiapine group showed response. Clozapine led to significantly greater side effects (P< 0.001, CI=2.241-6.059) on Glassgow Antipsychotic Side-effect Scale (GASS) than quetiapine.

CONCLUSIONS

Clozapine was found to be more efficacious than quetiapine in patients with TRS but was associated with greater side effects. Both the drugs were found to be equally effective in reducing the negative symptoms.

Inflammatory Cardiomyopathic Syndromes

Inflammatory activation occurs in nearly all forms of myocardial injury. In contrast, inflammatory cardiomyopathies refer to a diverse group of disorders in which inflammation of the heart (or myocarditis) is the proximate cause of myocardial dysfunction, causing injury that can range from a fully recoverable syndrome to one that leads to chronic remodeling and dilated cardiomyopathy. The most common cause of inflammatory cardiomyopathies in developed countries is lymphocytic myocarditis most commonly caused by a viral pathogenesis. In Latin America, cardiomyopathy caused by Chagas disease is endemic. The true incidence of myocarditis is unknown to the limited utilization and the poor sensitivity of endomyocardial biopsies (especially for patchy diseases such as lymphocytic myocarditis and sarcoidosis) using the gold-standard Dallas criteria. Emerging immunohistochemistry criteria and molecular diagnostic techniques are being developed that will improve diagnostic yield, provide additional clues into the pathophysiology, and offer an application of precision medicine to these important syndromes. Immunosuppression is recommended for patients with cardiac sarcoidosis, giant cell myocarditis, and myocarditis associated with connective tissue disorders and may be beneficial in chronic viral myocarditis once virus is cleared. Further trials of immunosuppression, antiviral, and immunomodulating therapies are needed. Together, with new molecular-based diagnostics and therapies tailored to specific pathogeneses, the outcome of patients with these disorders may improve.

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.

Clozapine-induced, dilated cardiomyopathy: a case report

Background

Clozapine is known to be a highly effective antipsychotic agent and additionally provides a significant reduction in suicide-risk and aggression. Clozapine-induced cardiomyopathy is a very rare but nonetheless dangerous side-effect, with an incidence of 0.02–0.1%, depending on the literature, and a mortality rate of up to 17.9%.

Case presentation

We report on the case of a 25 year-old patient, who was admitted for the evaluation of a potential electroconvulsive therapy due to persistent auditory hallucinations under clozapine. Shortly after admission he was found to be suffering from dilated cardiomyopathy, likely caused by his antipsychotic treatment.

Conclusion

Clozapine-induced cardiomyopathy should be taken into account when monitoring patients treated with this antipsychotic and regular electrocardiograms should be performed in order to detect possible alterations as soon as possible.

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.

Clozapine-induced hypersensitivity myocarditis presenting as sudden cardiac death

Hypersensitivity myocarditis is a rare but serious adverse effect of clozapine, a commonly used psychiatric drug. We report the case of sudden cardiac death from clozapine-induced hypersensitivity myocarditis diagnosed at autopsy. A 54-year-old Caucasian male on clozapine therapy for bipolar disorder presented with a sudden onset of shortness of breath. Laboratory studies were significant for elevated N-terminal prohormone of brain natriuretic peptide. During his hospital stay, the patient died of sudden cardiac arrest from ventricular tachycardia. The autopsy revealed hypersensitivity myocarditis, which usually occurs in the first 4 weeks after the initiation of clozapine. A 4-week monitoring protocol, including laboratory assessment of troponin and C-reactive protein, may assist in the early diagnosis of this potentially fatal condition.

Clozapine-Induced Gastrointestinal Hypomotility: A 22-Year Bi-National Pharmacovigilance Study of Serious or Fatal 'Slow Gut' Reactions, and Comparison with International Drug Safety Advice

INTRODUCTION

Clozapine is the preferred antipsychotic for treatment-resistant schizophrenia, but has significant adverse effects, including gastrointestinal hypomotility or 'slow gut', which may result in severe constipation, ileus, bowel obstruction, and even death. These gastrointestinal effects remain inadequately recognized.

METHODS

We reviewed all reports of serious clozapine-induced gastrointestinal hypomotility (CIGH) submitted to the Australian Therapeutic Goods Administration and New Zealand Pharmacovigilance Centre between 1992 and 2013. We extracted relevant demographic, clinical, and outcome data and derived a numerator from clozapine registries. We examined whether clozapine drug safety information in Australia, New Zealand, the US, and the UK was adequate and consistent with pharmacoepidemiologic evidence.

RESULTS

A total of 43,132 people commenced clozapine over the study period. 160 were reported as having serious gastrointestinal hypomotility with clozapine the suspected cause (37/10,000 clozapine users). Of these, 66.3% were male, age range was 17-76 years, clozapine dose range 25-1000 mg/day (mean 439 mg/day) and median duration of clozapine treatment 2.5 years. Few had received laxatives. At least 29 patients died (7/10,000 clozapine users), a reported case fatality rate of 18%. The CIGH prevalence, while similar to other smaller studies, differs significantly from clozapine prescribing information issued by regulators and pharmaceutical companies, none of which mention CIGH, and which report serious gastrointestinal complications at rates of <1/10,000, almost a 40-fold difference.

CONCLUSION

This is the largest study to date of serious CIGH. The reported prevalence of serious CIGH was 37/10,000, a likely underestimation of true prevalence. Current prescribing guidelines provide inadequate information on CIGH. This may be contributing to poor awareness and high associated morbidity and mortality. It is time regulators and manufacturers update their guidance.

Eosinophilic Drug Allergy

While peripheral or tissue eosinophilia may certainly characterize drug eruptions, this feature is hardly pathognomonic for a medication-induced etiology. While delayed drug hypersensitivity reactions with prominent eosinophilic recruitment have been typically classified as type IVb reactions, their pathophysiology is now known to be more complex. Eosinophilic drug reactions have a diversity of presentations and may be benign and self-limited to severe and life-threatening. The extent of clinical involvement is also heterogeneous, ranging from isolated peripheral eosinophilia or single organ involvement (most often the skin and lung) to systemic disease affecting multiple organs, classically exemplified by drug-reaction with eosinophilia and systemic symptoms (DRESS). The spectrum of implicated medications in the causation of DRESS is ever expanding, and multiple factors including drug metabolites, specific HLA alleles, herpes viruses, and immune system activation have been implicated in pathogenesis. Due to this complex interplay of various factors, diagnostic workup in terms of skin and laboratory testing has not been validated. Similarly, the lack of controlled trials limits treatment options. This review also describes other localized as well as systemic manifestations of eosinophilic disease induced by various medication classes, including their individual pathophysiology, diagnosis, and management. Given the multitude of clinical patterns associated with eosinophilic drug allergy, the diagnosis can be challenging. Considerable deficits in our knowledge of these presentations remain, but the potential for severe reactions should be borne in mind in order to facilitate diagnosis and institute appropriate management.

Clozapine-associated cardiac dysfunction during a gastroenteritis outbreak

We report that two young adult patients who were initiated with clozapine for severe psychosis during a hospital-wide gastroenteritis outbreak went into severe shock. Neither patient had troponin elevation. Each required left ventricular assist device support for myocarditis. Endomyocardial biopsy revealed lymphocytic myocarditis in one patient and eosinophilic myocarditis in the other. The former patient expired. Polymerase chain reaction testing was negative for Coxsackie virus. These two patients illustrate that myocarditis can occur at usual incipient doses and that there may be an epidemiologic risk associated with gastroenteritis. Although the white blood cell (WBC) count is expected to decrease with clozapine, these patients had persistently elevated WBC counts. In conclusion, physicians should exercise caution when prescribing clozapine, especially for those with diarrhea.

Probable clozapine-induced parenchymal lung disease and perimyocarditis: a case report

BACKGROUND

Clozapine is the archetypical atypical antipsychotic, its primary indication being treatment resistant schizophrenia. Severe side effects caused by clozapine, including leukopenia, agranulocytosis, and myocarditis, are well known. A rarely described side effect is concurrent perimyocarditis and parenchymal lung disease.

CASE PRESENTATION

A previously physically healthy 23-year-old male Caucasian that suffered from schizophrenia presented with flu-like symptoms 1 week after starting clozapine treatment. Treatment with clozapine was discontinued. He developed respiratory distress. Investigations showed significant parenchymal infiltration in both of the lungs, pericardial fluid, and heart failure. He initially received treatment for suspected malignant neuroleptic syndrome and later for suspected infection, but these tentative diagnoses were not confirmed. The patient's condition gradually improved. In retrospect, clozapine-induced parenchymal lung disease and perimyocarditis were deemed the most probable causes.

CONCLUSIONS

Concurrent perimyocarditis and parenchymal lung disease are rare side effects of clozapine. Clozapine-induced disease in general is considered an exclusion diagnosis. Lacking a verifiable diagnosis when suspecting a side effect of clozapine, clinicians might treat the most likely and serious condition presenting and consider discontinuing clozapine until the diagnostic uncertainty is reasonably resolved.

The Quest for New Approaches in Myocarditis and Inflammatory Cardiomyopathy

Myocarditis is a diverse group of heart-specific immune processes classified by clinical and histopathological manifestations. Up to 40% of dilated cardiomyopathy is associated with inflammation or viral infection. Recent experimental studies revealed complex regulatory roles for several microribonucleic acids and T-cell and macrophage subtypes. Although the prevalence of myocarditis remained stable between 1990 and 2013 at about 22 per 100,000 people, overall mortality from cardiomyopathy and myocarditis has decreased since 2005. The diagnostic and prognostic value of cardiac magnetic resonance has increased with new, higher-sensitivity sequences. Positron emission tomography has emerged as a useful tool for diagnosis of cardiac sarcoidosis. The sensitivity of endomyocardial biopsy may be increased, especially in suspected sarcoidosis, by the use of electrogram guidance to target regions of abnormal signal. Investigational treatments on the basis of mechanistic advances are entering clinical trials. Revised management recommendations regarding athletic participation after acute myocarditis have heightened the importance of early diagnosis.

Drugs That May Cause or Exacerbate Heart Failure: A Scientific Statement From the American Heart Association

Heart failure is a common, costly, and debilitating syndrome that is associated with a highly complex drug regimen, a large number of comorbidities, and a large and often disparate number of healthcare providers. All of these factors conspire to increase the risk of heart failure exacerbation by direct myocardial toxicity, drug-drug interactions, or both. This scientific statement is designed to serve as a comprehensive and accessible source of drugs that may cause or exacerbate heart failure to assist healthcare providers in improving the quality of care for these patients.

Lessons Learned and Questions Raised by an Atypical Case of Clozapine-Induced Myocarditis

A Caucasian male in his early twenties suffering from treatment resistant schizophrenia was started on clozapine. After three days he developed tachycardia, a common side effect of clozapine induction. He had one temperature spike (38.9°C) on day ten after induction but remained clinically well. An ECG and blood tests were normal. Due to persistent tachycardia and an episode of collapse whilst seated on day 12, he was admitted to hospital for further investigation. A diagnosis of myocarditis was confirmed as a result of elevated cardiac enzyme levels and an echocardiogram. Following withdrawal of clozapine, supportive management, and initiation of cardiac medication, the patient made a successful recovery. He will be followed up with the cardiology team to ensure that his heart function returns to normal. Given the incidence of clozapine-induced myocarditis, the associated mortality risk, and diagnostic difficulties, this case raises questions about whether a formal system for identifying myocarditis should be adopted.

Systematic Review of Clozapine Cardiotoxicity

Clozapine is exceptionally effective in psychotic disorders and can reduce suicidal risk. Nevertheless, its use is limited due to potentially life-threatening adverse effects, including myocarditis and cardiomyopathy. Given their clinical importance, we systematically reviewed research on adverse cardiac effects of clozapine, aiming to improve estimates of their incidence, summarize features supporting their diagnosis, and evaluate proposed monitoring procedures. Incidence of early (≤2 months) myocarditis ranges from <0.1 to 1.0 % and later (3-12 months) cardiomyopathy about 10 times less. Diagnosis rests on relatively nonspecific symptoms, ECG changes, elevated indices of myocardial damage, cardiac MRI findings, and importantly, echocardiographic evidence of developing ventricular failure. Treatment involves stopping clozapine and empirical applications of steroids, diuretics, beta-blockers, and antiangiotensin agents. Mortality averages approximately 25 %. Safety of clozapine reuse remains uncertain. Systematic studies are needed to improve knowledge of the epidemiology, avoidance, early identification, and treatment of these adverse effects, with effective and practicable monitoring protocols.

Rapid Clozapine Titration in Patients with Treatment Refractory Schizophrenia

The aim of this study is to evaluate the safety and effectiveness of rapid clozapine titration in patients with schizophrenia in hospital settings. We conducted a retrospective two-center cohort study to compare the safety and effectiveness of clozapine with different titration rates in treatment-refractory patients with schizophrenia. In the first center, clozapine was started at 25-50 mg followed by 50-100 mg as needed every 6 h on day 1, followed by increases of 50-100 mg/day. In the second center, titration was slower; clozapine initiated with 12.5-50 mg on day 1 followed by increases of 25-50 mg/day. The number of days between starting of clozapine until discharge was shorter in the rapid titration group (22.4 ± 8.72 vs 27.0 ± 10.5, p = 0.1). Number of days of total hospital stay were significantly shorter in the rapid titration group (29.6 ± 10.6 vs 41.2 ± 14.8, p = 0.002). Hypotension was more common in the rapid titration group and one patient had suspected myocarditis. Rapid clozapine titration appeared safe and effective. The length of stay following initiation of clozapine was shorter in the rapid-titration group, although this was not statistically significant. However starting clozapine earlier together with rapid titration has significantly shortened the length of hospital stay in patients with treatment refractory schizophrenia.

Inflammatory response to clozapine in the absence of myocarditis: case report

SUMMARY

A case is presented of a 25-year-old man with treatment-resistant paranoid schizophrenia whose only previous trial of clozapine had been stopped following a suspected clozapine-induced myocarditis. Due to the failure of his psychosis to respond to a number of antipsychotic treatments and augmentation strategies, clozapine was restarted on admission. His rechallenge was marked by intermittent pyrexia, tachycardia and elevated C-reactive protein (CRP), but eosinophilia was absent. Clozapine was started and then stopped twice following extensive investigation and with specialist cardiology consultation. Physical symptoms and CRP elevation resolved shortly after clozapine cessation. We believe this constituted an idiosyncratic systemic inflammatory response to clozapine treatment.

DECLARATION OF INTEREST

None.

COPYRIGHT AND USAGE

© The Royal College of Psychiatrists 2016. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Incidence and risk factors for clozapine-induced myocarditis and cardiomyopathy at a regional mental health service in Australia

OBJECTIVE

To determine the incidence of clozapine-induced myocarditis and cardiomyopathy and identify risk factors.

METHOD

A cohort of 129 patients initiated on clozapine at Toowoomba Mental Health Service from year 2000 until 2011 was examined to evaluate cases of myocarditis and cardiomyopathy. Risk factors were analysed using multivariable logistic regression.

RESULTS

The incidence of clozapine-induced myocarditis and cardiomyopathy was 3.88% and 4.65% (or 2.26 per 100 patient years), respectively. A significant association was identified between clozapine-induced myocarditis and SSRI use (p = 0.043). Subclinical cardiomyopathy was identified in the absence of symptoms in the majority of cases.

CONCLUSIONS

These results illustrate a high incidence of clozapine-induced myocarditis as well as cardiomyopathy, reinforcing the need for a standardised, mandatory monitoring scheme. Concomitant SSRI use as one such potential predictor merits further study.

Clozapine in Parkinsonian Rest Tremor: A Review of Outcomes, Adverse Reactions, and Possible Mechanisms of Action

BACKGROUND

The pathogenesis of rest tremor in Parkinson's disease (PD) is incompletely understood. This symptom can be resistant to typical anti-PD medications. Therefore, new treatments are needed given the concern that this symptom causes to patients and family. Limited experience suggests that clozapine can have an important antitremor effect in PD. The mechanism(s) underlying this effect is not well understood, but could provide insight and impetus to the development of more-effective and safer antitremor therapies.

METHODS AND RESULTS

Exemplifying the antitremor effects of clozapine, we describe a patient with tremor-predominant PD who obtained prominent reduction of rest tremor with clozapine treatment. We review the responses to this treatment in another 7 of our PD patients with treatment-resistant rest tremor. We also review the published literature on clozapine for tremor in PD and discuss its potential mechanisms of action and possible adverse effects. In our case series, there was a 64% reduction of tremor score after clozapine was initiated. The mechanism of tremor reduction remains unclear with possible involvement of anticholinergic, serotonergic, antihistaminergic, antiadrenergic, and antidopaminergic effects. Clozapine does have potential serious adverse effects.

CONCLUSIONS

Clozapine may be effective in controlling rest tremor in PD. Given the potential fatal side effects, if clozapine is to be initiated in PD patients, it has to be used cautiously with proper monitoring, preferably in specialized centers. We acknowledge that the number of patients in this case series is small. Further studies are needed to understand clozapine's mechanism of action in reducing tremor.

Methods for the estimation of the National Institute for Health and Care Excellence cost-effectiveness threshold

BACKGROUND

Cost-effectiveness analysis involves the comparison of the incremental cost-effectiveness ratio of a new technology, which is more costly than existing alternatives, with the cost-effectiveness threshold. This indicates whether or not the health expected to be gained from its use exceeds the health expected to be lost elsewhere as other health-care activities are displaced. The threshold therefore represents the additional cost that has to be imposed on the system to forgo 1 quality-adjusted life-year (QALY) of health through displacement. There are no empirical estimates of the cost-effectiveness threshold used by the National Institute for Health and Care Excellence.

OBJECTIVES

(1) To provide a conceptual framework to define the cost-effectiveness threshold and to provide the basis for its empirical estimation. (2) Using programme budgeting data for the English NHS, to estimate the relationship between changes in overall NHS expenditure and changes in mortality. (3) To extend this mortality measure of the health effects of a change in expenditure to life-years and to QALYs by estimating the quality-of-life (QoL) associated with effects on years of life and the additional direct impact on QoL itself. (4) To present the best estimate of the cost-effectiveness threshold for policy purposes.

METHODS

Earlier econometric analysis estimated the relationship between differences in primary care trust (PCT) spending, across programme budget categories (PBCs), and associated disease-specific mortality. This research is extended in several ways including estimating the impact of marginal increases or decreases in overall NHS expenditure on spending in each of the 23 PBCs. Further stages of work link the econometrics to broader health effects in terms of QALYs.

RESULTS

The most relevant 'central' threshold is estimated to be £12,936 per QALY (2008 expenditure, 2008-10 mortality). Uncertainty analysis indicates that the probability that the threshold is < £20,000 per QALY is 0.89 and the probability that it is < £30,000 per QALY is 0.97. Additional 'structural' uncertainty suggests, on balance, that the central or best estimate is, if anything, likely to be an overestimate. The health effects of changes in expenditure are greater when PCTs are under more financial pressure and are more likely to be disinvesting than investing. This indicates that the central estimate of the threshold is likely to be an overestimate for all technologies which impose net costs on the NHS and the appropriate threshold to apply should be lower for technologies which have a greater impact on NHS costs.

LIMITATIONS

The central estimate is based on identifying a preferred analysis at each stage based on the analysis that made the best use of available information, whether or not the assumptions required appeared more reasonable than the other alternatives available, and which provided a more complete picture of the likely health effects of a change in expenditure. However, the limitation of currently available data means that there is substantial uncertainty associated with the estimate of the overall threshold.

CONCLUSIONS

The methods go some way to providing an empirical estimate of the scale of opportunity costs the NHS faces when considering whether or not the health benefits associated with new technologies are greater than the health that is likely to be lost elsewhere in the NHS. Priorities for future research include estimating the threshold for subsequent waves of expenditure and outcome data, for example by utilising expenditure and outcomes available at the level of Clinical Commissioning Groups as well as additional data collected on QoL and updated estimates of incidence (by age and gender) and duration of disease. Nonetheless, the study also starts to make the other NHS patients, who ultimately bear the opportunity costs of such decisions, less abstract and more 'known' in social decisions.

FUNDING

The National Institute for Health Research-Medical Research Council Methodology Research Programme.

Higher than expected clozapine serum level and clozapine/norclozapine ratio due to CYP450 gene polymorphisms

Aims: We investigated a case of the unexpectedly high clozapine/norclozapine serum levels in a non-smoker, female patient. Method: The RFLP genotype method was used for the loss-of-function CYP450 gene polymorphisms detection. Results: The genotype revealed the presence of CYP2D6*41/*41, rs28371725, NM_000106.5:c.985+39G>A and CYP1A2*1/*1D rs35694136, NM_000761.4:c.-1635delT. Conclusion: An appropriate clozapine serum level is required for both optimization of clinical response and avoidance of troublesome, or even life-threatening side effects. Although not the only factor, genetic polymorphisms responsible for the metabolism of clozapine play an important role towards such goals. Pharmacogenetic tests can guide dose adjustment in order to obtain an optimum serum level, which can lead to a better therapeutic response and minimization of harmful side effects.

Clozapine-induced myocarditis, a widely overlooked adverse reaction

OBJECTIVE

We review the published cases of clozapine-induced myocarditis and describe reasons for the higher incidence in Australia (>1%) than elsewhere (<0.1%).

METHOD

Medline was searched to September 2014 using 'clozapine' as the sole term.

RESULTS

A total of around 250 cases of clozapine-induced myocarditis have been published. Fever among patients commencing clozapine has been reported internationally, and very few of these cases were investigated for myocarditis. The time to onset of fever is consistent with its being part of a prodrome of undiagnosed myocarditis, and the risk factors are similar to those for myocarditis. In more severe cases, clozapine is discontinued, avoiding fatalities which may occur with myocarditis. Furthermore, cases of sudden death and respiratory illness may well have been undiagnosed myocarditis. The diagnosis of myocarditis is confounded by the non-specific nature of the signs and symptoms, and it depends on appropriate investigations being conducted at the time of myocardial involvement or, for fatal cases, the affected area of the myocardium being sampled for histology.

CONCLUSION

It is likely that the incidence of myocarditis is around 3%. Implementation of monitoring procedures will increase case ascertainment and result in more patients benefiting from this valuable medication.

Impairment of left ventricular function early in treatment with clozapine: a preliminary study

This preliminary prospective study evaluated cardiac status in 15 treatment-resistant schizophrenia patients (aged 18-55 years) without evidence of cardiovascular disease. Patients underwent clinical assessment, blood tests, ECG, and echocardiography before and during clozapine treatment for 4 weeks as doses increased from 25 to 100 mg/day. Serum concentrations of high-sensitivity C-reactive protein, troponin-I, brain natriuretic peptide, and clozapine+norclozapine were assayed at week 3; ECG and echocardiography were repeated at week 4. At moderate serum drug concentrations (124 ng/ml), the heart rate increased by 10% and high-sensitivity C-reactive protein levels were slightly elevated, but troponin-I and brain natriuretic peptide levels were not elevated. Echocardiographic indices indicated declining left ventricular (LV) diastolic and systolic function in 60-80% of participants, with an increase in systolic pulmonary artery pressure, A-wave velocity, and LV myocardial performance index by 16-24% in 60-80% of participants and a decrease in the E/A ratio by 29% in 73% of participants - all uncorrelated with drug concentrations. Early treatment with moderate doses of clozapine was associated with subclinical but substantial decreases in LV functioning in surprisingly high proportions of participants. Studies with more participants, higher drug doses, and long-term follow-up are needed to confirm and determine the course of the observed abnormalities and to evaluate their relationship with rare clinical cardiotoxicity associated with clozapine.

A Case of Clozapine-Induced Myocarditis in a Young Patient with Bipolar Disorder

We present a case of drug-induced myocarditis manifesting as acute heart failure in a young patient with bipolar disorder being treated for depression. The case describes a 20-year-old man being treated in the psychiatry ward for worsening depression when he started complaining of chest pain and shortness of breath. His list of medications included clozapine, lithium, lorazepam, and haloperidol. The main findings on physical examination were tachycardia, low-grade fever, crackles in both lung bases on auscultation, and the absence of any notable edema. Abnormal labs included a troponin of 0.9, with a CK of 245 and CK-MB of 3.1. An ECG revealed sinus tachycardia and left anterior fascicular block (LAFB). An echocardiogram revealed global hypokinesis, severe left ventricular dysfunction with an ejection fraction estimated at 20%. The patient had an admitting diagnosis of acute left ventricular systolic dysfunction likely secondary to drug-induced myocarditis (suspect clozapine) versus acute coronary syndrome. He was managed conservatively and transferred to another facility for endomyocardial biopsy confirming myocarditis. This case is an example of one of the most typical presentations of suspected drug-induced acute myocarditis and will hopefully prompt the reader to think of this underdiagnosed entity in the right clinical setting.

Effectiveness of ultra-rapid dose titration of clozapine for treatment-resistant bipolar mania: case series

Treatment of severe and refractory manic episodes in hospital settings can occasionally be very difficult. In particular, severely excited patients showing aggressive, hostile, impulsive behaviours frequently require physical restraint and seclusion, high doses of antipsychotics and benzodiazepines, and sometimes, electroconvulsive therapy. Hospital stay is generally prolonged and such patients cause great emotional distress for other patients in the ward and clinical staff involved in their care. Here we report on three patients with a diagnosis of bipolar disorder and one patient with a diagnosis of schizoaffective disorder bipolar subtype, all of whom were hospitalized for severe manic episodes with psychotic features. These patients were extremely difficult to manage in the ward as no response could be obtained in the first week of treatment despite high doses of antipsychotics and benzodiazepine administration. The introduction and rapid titration of clozapine proved remarkably effective and was well tolerated in the acute management of these patients. We observed that clozapine had a superior and fast mood stabilization effect with rapid titration and could be extremely helpful in the management of such patients.

The global burden of myocarditis: part 1: a systematic literature review for the Global Burden of Diseases, Injuries, and Risk Factors 2010 study

Myocarditis contributes to the global burden of cardiovascular disease primarily through sudden death and dilated cardiomyopathy. A systematic approach to identify the cardiovascular mortality and major morbidity attributable to myocarditis has not been performed. A writing group convened by the GBD 2010 (Global Burden of Diseases, Injuries and Risk Factors) Study systematically reviewed the world's literature by a manual review of all titles since 1966 on myocarditis identified using Ovid Medline, development of a disease model, and provision of estimates when possible of the incidence, prevalence, risk of death, and major morbidity for the world regions. Accurate population-based estimates of myocarditis incidence and prevalence are not directly available in any world region. However, a model that quantitates the risk of acute death and chronic heart failure following myocarditis was derived from the published data. Using hospital dismissal data, the burden of myocarditis as a percentage of prevalent heart failure varied by age and region from approximately 0.5% to 4.0%. The novel combination of multiple data sources may provide an estimate of the years of life lost and years of life disabled from myocarditis. Pending the integration of these data sources, the burden of dilated cardiomyopathy and myocarditis were reported together in the 2010 GBD report. The 2013 GBD project may refine these estimates with the inclusion of more comprehensive payor databases and more precise case definitions.

Comparison of trapping profiles between d-peptides and glutathione in the identification of reactive metabolites

Qualitative trapping profile of reactive metabolites arising from six structurally different compounds was tested with three different d-peptide isomers (Peptide 1, gly–tyr–pro–cys–pro–his-pro; Peptide 2, gly–tyr–pro–ala–pro–his–pro; Peptide 3, gly–tyr–arg–pro–cys–pro–his–lys–pro) and glutathione (GSH) using mouse and human liver microsomes as the biocatalyst. The test compounds were classified either as clinically “safe” (amlodipine, caffeine, ibuprofen), or clinically as “risky” (clozapine, nimesulide, ticlopidine; i.e., associated with severe clinical toxicity outcomes). Our working hypothesis was as follows: could the use of short different amino acid sequence containing d-peptides in adduct detection confer any add-on value to that obtained with GSH? All “risky” agents’ resulted in the formation of several GSH adducts in the incubation mixture and with at least one peptide adduct with both microsomal preparations. Amlodipine did not form any adducts with any of the trapping agents. No GSH and peptide 2 and 3 adducts were found with caffeine, but with peptide 1 one adduct with human liver microsomes was detected. Ibuprofen produced one Peptide 1-adduct with human and mouse liver microsomes but not with GSH. In conclusion, GSH still remains the gold trapping standard for reactive metabolites. However, targeted d-peptides could provide additional information about protein binding potential of electrophilic agents, but their clinical significance needs to be clarified using a wider spectrum of chemicals together with other safety estimates.

Clozapine linked to nanocapsules minimizes tissue and oxidative damage to biomolecules lipids, proteins and DNA in brain of rats Wistar

Clozapine, atypical antipsychotic, can change oxidative stress parameters. It is known that reactive species, in excess, can have a crucial role in the etiology of diseases, as well as, can potentiating adverse effects induce by drugs. The nanocapsules have attracted attention as carriers of several drugs, with consequent reduction of adverse effects. This study aimed to evaluate histopathology and oxidative damage of biomolecules lipids, proteins and DNA in the brain of Wistar rats after treatment with nanocapsules containing clozapine. The study consisted of eight groups of male Wistar rats (n = 6): saline (SAL), free clozapine (CZP) (25 mg/Kg i.p.), blank uncoated nanocapsules (BNC), clozapine-loaded uncoated nanocapsules (CNC) (25 mg/Kg i.p.), blank chitosan-coated nanocapsules (BCSN), clozapine-loaded chitosan-coated nanocapsules (CCSN) (25 mg/Kg i.p.), blank polyethyleneglycol-coated nanocapsules (BPEGN), clozapine-loaded polyethyleneglycol-coated nanocapsules (CPEGN) (25 mg/Kg i.p.). The animals received the formulation once a day for seven consecutive days and euthanized in the eighth day. After euthanasia, the brain was collected and homogenate was processed for further analysis. The histopathology showed less brain tissue damage in nanocapsules-treated groups. The lipid peroxidation and carbonylation of proteins showed a significant increase (p < 0.05) induced by CZP. CNC and CPEGN groups obtained a reduction membrane of lipids damage and nanocapsules-treated groups showed significant improvement protein damage. CZP was able to induce genetic oxidative damage, while the nanocapsules causing less damage to DNA. The findings show that different coatings can act protecting target tissues decreasing oxidative damage, suggesting that the drug when linked to different nanocapsules is able to mitigate the harmful effects of clozapine.

Clozapine-induced myocarditis: recognizing a potentially fatal adverse reaction

A 46-year-old man with a history of paranoid schizophrenia was admitted with a recurrence of psychotic symptoms. Improvement was noted after the initiation of clozapine. After 2 weeks of clozapine therapy, chest pressure and abnormal cardiac biomarkers (in the presence of a normal coronary angiogram) raised suspicion of myocarditis. That diagnosis was confirmed by means of cardiac magnetic resonance imaging. Discontinuation of the clozapine led to resolution of the cardiac symptoms. Clozapine-induced myocarditis is rare and can be missed for lack of specific clinical findings. In order to prevent disease progression and a possibly fatal outcome, early recognition of the condition and prompt discontinuation of clozapine are necessary.

Clozapine-induced cardiotoxicity in rats: Involvement of tumour necrosis factor alpha, NF-κβ and caspase-3

Clozapine, an ideal antipsychotic drug for the treatment of resistant schizophrenia, is considered the most underutilised treatment for schizophrenia. However, safety concerns have been raised about clozapine-induced cardiotoxicity, which may lead to sudden death, particularly in young patients. The exact mechanism of clozapine cardiotoxicity has not yet been thoroughly studied. This study aimed to investigate the possible mechanisms of clozapine-induced cardiotoxicity in a rat model. Young male Wistar rats were treated with clozapine (10, 15 and 25 mg/kg/day, i.p.) for 21 days. Haemodynamic and echocardiographic studies were performed for assessment of cardiac functions. Heart sections were studied histopathologically and immunohistochemically. Serum and cardiac markers of cardiotoxicity, oxidative stress, inflammation and apoptosis were evaluated. Heart sections of CLZ-treated animals showed increased cardiac inflammation that correlated with the clozapine dose. Serum levels of CK-MB and LDH levels increased, as did cardiac levels of TNF-α, MDA, NO, myeloperoxidase (MPO), 8-OHdG, caspase-3 and NF-κB p65. In contrast, GSH levels and GSH-Px activity decreased. Furthermore, immunohistochemical examination of the heart sections showed positive immunostaining for both 3-nitrotyrosine and caspase-3 in all clozapine-treated groups. Clozapine, particularly in relatively high doses, has a clear cardiotoxic effect. This cardiotoxicity is accompanied by increased myocardial oxidative stress, inflammatory cytokines, DNA damage and apoptosis with attenuation in antioxidant defences, thus explaining the previously reported myocarditis and pericarditis during clozapine therapy in clinical studies.

Managing cardiovascular disease risk in patients treated with antipsychotics: a multidisciplinary approach

Background

The use of antipsychotic medication in the United States and throughout the world has greatly increased over the last fifteen years. These drugs have significant side effect burdens, many of them relating to cardiovascular health.

Objective

To review the available evidence on the major cardiovascular issues that arise in patients taking antipsychotic medication.

Method

A PubMed literature review was performed to identify recent meta-analyses, review articles, and large studies. Further articles were identified through cited papers and based on expert consultation when necessary.

Results

Clinical guidance on the following adverse effects and antipsychotics was reviewed: electrocardiogram (ECG) changes, (specifically, prolonged QT and risk of torsades de pointes), weight gain, dyslipidemia, metabolic syndrome, and myocarditis. Specific attention was paid to monitoring guidelines and treatment options in the event of adverse events, including dose change, medication switch, or adjuvant therapy.

A naturalistic comparison of the long-term metabolic adverse effects of clozapine versus other antipsychotics for patients with psychotic illnesses

OBJECTIVE

Clozapine, an evidence-based treatment of refractory schizophrenia, is associated with increased weight gain and metabolic dysregulation compared with most antipsychotics in short-term clinical trials. However, there are limited data describing comparative long-term metabolic risks. In this report, we examined whether short-term differences persist with long-term exposure to clozapine.

METHODS

The data of all patients in a university-based clinic with a psychotic illness or a mood disorder with psychotic features, based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision diagnosis, and treated with an antipsychotic in calendar year 2012 were examined. A total of 307 patients met the criteria; 96 patients were treated with clozapine and the remaining 211 patients were treated with 1 or more non-clozapine antipsychotics. Body mass index, type 2 diabetes, hypertension, dyslipidemia, and obesity were compared.

RESULTS

The mean duration of the clozapine treatment was 7.6 years (range, 2 months to 21 y). On all metabolic measures, there were no statistically significant differences between the clozapine and non-clozapine groups (mean body mass index, 31 vs 32; type 2 diabetes, 17% vs 18%; dyslipidemia, 35% vs 38%; hypertension, 32% vs 39%; and obesity, 48% vs 54%). Removing the olanzapine-treated patients (n = 51) from the non-clozapine group did not change the findings.

CONCLUSIONS

In this university-based clinic sample with a large number of clozapine-treated patients, we found no evidence of increased risk in any individual measure for those receiving clozapine. Although speculative, the relative contribution of the increased short-term metabolic risk associated with clozapine may be diminished over time because multiple other variables likely also impact metabolic risk during the life span. Although speculative, the relative contribution of the increased short-term metabolic risk associated with clozapine may be diminished over time due to the accumulated impact of other variables that also impact metabolic risk across the life span.

Effectiveness and safety of rapid clozapine titration in schizophrenia

OBJECTIVE

Clinical guidelines recommend slow clozapine dose titration in order to decrease the risk of seizures and hypotension. The recommendation may delay adequate control of severe psychotic symptoms. We evaluated the safety and effectiveness of rapid clozapine titration in patients who had been previously exposed to the drug and in patients who received clozapine for the first time after failing to respond to other antipsychotics.

METHOD

Analysis of hospital course of a consecutive cohort of schizophrenia patients (N = 111) who received 25-100 mg of clozapine as needed every 6 h the first treatment day, followed by upward adjustments of 25-100 mg/day.

RESULTS

Symptom control was obtained with an average dose of 353 ± 174 mg/day after 4.1 ± 3.1 days in the 73 patients previously treated with clozapine. For the 38 patients initially started on other antipsychotics, the average clozapine dose required for symptom control (409 ± 188 mg/day) was reached after 7.1 ± 4.8 days. None of the patients had seizures, severe hypotension or other major adverse reactions.

CONCLUSION

In this naturalistic cohort study rapid clozapine titration appeared safe and effective for the treatment of schizophrenia. The results justify controlled clinical trials of this treatment method.