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

Clozapine-induced antineutrophil cytoplasmic antibody-associated vasculitis: a case report

Clozapine is the most effective antipsychotic medication for refractory schizophrenia, but it has many possible serious side effects, including antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, the rare case reports available have not presented sufficient characteristic features of drug-induced AAV. Herein, we report a case of a 48-year-old Japanese woman with schizophrenia who presented with fever, arthralgia, myalgia and skin rash after 2 years of clozapine treatment. Her C-reactive protein (CRP) level increased, myeloperoxidase ANCA was positive and skin biopsy revealed leukocytoclastic vasculitis. Initially, steroid administration achieved remission, but her symptoms and high CRP levels relapsed every time the steroid dosage was tapered down. Upon discontinuation of clozapine, her symptoms and elevated CRP level immediately improved and the steroid was successfully tapered and discontinued. This outcome suggested that clozapine was the main cause of AAV.

Clozapine-induced bicytopenia: An unusual side effect

Agranulocytosis is a rare documented side effect of clozapine which can be associated with grave consequences. When it is associated with other blood dyscrasia, prognosis worsens further. In literature, there are very few cases of pancytopenia and bicytopenia caused by clozapine. We present a case of bicytopenia (reduced white and red blood cells' counts) caused by clozapine within a month of therapy and complicated by a Klebsiella pneumoniae infection. Patient improved in 3 weeks after stopping clozapine along with medical management in the Intensive Care Unit. Such side effects, though rare, can be life threatening and warrants intermittent complete blood monitoring besides regular assessment of granulocytes and neutrophils when any patient is prescribed clozapine.

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.

The impact of antipsychotics as a risk factor for thromboembolism

Patients with schizophrenia are predisposed toward developing cardiovascular disease. Although neuroleptics affect the cardiovascular system, it is also important to consider the consequences of the disease itself such as lower physical activity due to living on disability pension, inadequate nutrition, and/or nicotine addiction, being more common among patients with schizophrenia versus the general population. All these factors combined lead to an increased risk of death caused by cardiovascular conditions in schizophrenic patients. Individuals receiving typical antipsychotic drugs have been reported to have elevated concentrations of antiphospholipid antibodies, including anticoagulants and anticardiolipin antibodies. The presence of both antibodies is associated with an increased risk for thromboembolism. It is also likely that mental illness is accompanied by increased procoagulant activity. Patients with acute psychosis have been shown to have a statistically significant increase in the concentrations of D-dimer, P-selectin, and in the expression of platelet glycoprotein IIb/IIIa receptors. Learning about causes and mechanisms of venous thromboembolism could help to reduce or neutralize the adverse effects of antipsychotic treatment and facilitate the identification of appropriate markers necessary to monitor changes and provide preventive care against hazardous and potentially fatal complications such as deep venous thrombosis and pulmonary embolism. Before atypical neuroleptic treatment is administered to hospitalized patients, all possible risk factors for thromboembolism should be considered to allow the application of lower risk drugs. Also, other preventive measures should be taken into account, including hydration, compression stockings, regular exercise of lower extremities, and low-molecular-weight heparin injections.

Biological substantiation of antipsychotic-associated pneumonia: Systematic literature review and computational analyses

Introduction

Antipsychotic (AP) safety has been widely investigated. However, mechanisms underlying AP-associated pneumonia are not well-defined.

Aim

The aim of this study was to investigate the known mechanisms of AP-associated pneumonia through a systematic literature review, confirm these mechanisms using an independent data source on drug targets and attempt to identify novel AP drug targets potentially linked to pneumonia.

Methods

A search was conducted in Medline and Web of Science to identify studies exploring the association between pneumonia and antipsychotic use, from which information on hypothesized mechanism of action was extracted. All studies had to be in English and had to concern AP use as an intervention in persons of any age and for any indication, provided that the outcome was pneumonia. Information on the study design, population, exposure, outcome, risk estimate and mechanism of action was tabulated. Public repositories of pharmacology and drug safety data were used to identify the receptor binding profile and AP safety events. Cytoscape was then used to map biological pathways that could link AP targets and off-targets to pneumonia.

Results

The literature search yielded 200 articles; 41 were included in the review. Thirty studies reported a hypothesized mechanism of action, most commonly activation/inhibition of cholinergic, histaminergic and dopaminergic receptors. In vitro pharmacology data confirmed receptor affinities identified in the literature review. Two targets, thromboxane A2 receptor (TBXA2R) and platelet activating factor receptor (PTAFR) were found to be novel AP target receptors potentially associated with pneumonia. Biological pathways constructed using Cytoscape identified plausible biological links potentially leading to pneumonia downstream of TBXA2R and PTAFR.

Conclusion

Innovative approaches for biological substantiation of drug-adverse event associations may strengthen evidence on drug safety profiles and help to tailor pharmacological therapies to patient risk factors.

The Efficacy and Safety of Antipsychotic Medications in the Treatment of Psychosis in Patients with Parkinson's Disease

Psychotic symptoms are present in up to 50% of patients with Parkinson's disease. These symptoms have detrimental effects on patients' and caregivers' quality of life and may predict mortality. The pathogenesis of psychotic symptoms in Parkinson's disease is complex, but the use of dopaminergic medications is one of the risk factors. The treatment of psychotic symptoms in Parkinson's disease is complicated due to the ability of antipsychotic medications to worsen motor symptoms. The efficacy of clozapine in the treatment of psychosis in patients with Parkinson's disease has been confirmed in several clinical trials; however, the adverse effects and the necessity of blood count monitoring are the reasons why the use of this drug is challenging. The studies on safety and efficacy of other antipsychotics conflicting results. The use of antipsychotics in these patients is also associated with increased mortality. Psychotic symptoms in Parkinson's disease per se are also proven predictors of mortality. Thus it is necessary to treat psychotic symptoms but the choice of an antipsychotic should be based on careful risk/benefit assessment. Pimavanserin as a novel therapeutic option with more favorable adverse effects profile is now available for this indication, but careful postmarketing monitoring is necessary to establish the true picture of this drug's long-term safety and efficacy.

Late Onset Agranulocytosis with Clozapine Associated with HLA DR4 Responding to Treatment with Granulocyte Colony-stimulating Factor: A Case Report and Review of Literature

Agranulocytosis as a side effect of clozapine has been reported to be associated with initial phases of treatment, i.e., first six months. Agranulocytosis with clozapine during the initial phases of treatment has been linked to genetic vulnerability in the form of variations in the human leukocyte-antigen haplotypes. However, there is limited literature on late onset agranulocytosis with clozapine and this has very rarely been linked to human leukocyte-antigen haplotypes vulnerability. In this report we review the existing data on late onset agranulocytosis with clozapine and describe the case of a young man, who developed agranulocytosis with clozapine after 35 months of treatment and was found to have genetic vulnerability in form of being positive for HLA DR4. This case highlights underlying autoimmune immune mechanism in clozapine-induced agranulocytosis and the need for frequent blood count monitoring on clozapine even after the initial 6 months of starting treatment especially in patients with genetic vulnerability to develop this condition.

Clozapine induced pancytopenia leading to severe sepsis: an unusual early complication

BACKGROUND

Clozapine is a second generation antipsychotic used to treat resistant schizophrenia and other psychotic illnesses. Leucopenia or agranulocytosis is a rare side effect of this drug. Pancytopenia is an extremely rare side effect of clozapine and literature review showed only one such case in where the pancytopenia developed several months after starting clozapine together with other antipsychotic drugs.

CASE PRESENTATION

A 26-year-old Sri Lankan male was admitted with fever for 3 days. Apart from generalized body aches there were no other significant symptoms. His blood counts showed pancytopenia. He was being treated for a resistant schizophrenia and clozapine was started only 4 weeks before. Common causes for pancytopenia were excluded, and a diagnosis of clozapine induced pancytopenia was made. He was managed in the intensive care unit with broad spectrum antibiotics, antifungals and granulocyte colony stimulating factors. He made a complete recovery after 4 weeks.

CONCLUSION

This is a rare and probably the first reported case of early onset clozapine induced pancytopenia complicated by severe sepsis recovering completely.