Successful rechallenge with clozapine after treatment associated eosinophilia

Clozapine-induced eosinophilia: A case report

Schizophrenia is a chronic neuropsychiatric illness defined by the appearance of positive, and negative symptoms and/or cognitive impairment. Antipsychotic drugs are predominantly used in the treatment of psychotic disorders, but not all patients with schizophrenia respond to every antipsychotic medication. Clozapine is one of the best atypical antipsychotics and is highly effective in treating treatment-resistant schizophrenia. Evidence suggests that clozapine appears to be effective in lowering the risk of suicide, extrapyramidal side effects, and relapse in patients with schizophrenia. Per contra, clozapine is not the first-line treatment due to its unalterable aftereffects such as agranulocytosis, metabolic syndrome, seizures, and rarely, eosinophilia. Eosinophilia can be life-threatening. Eosinophils infiltrate different tissues and cause inflammation in multiple organs causing end-organ damage. The current study aimed to report the incidence of eosinophilia associated with clozapine use in patients with schizophrenia. Literature on clozapine-induced eosinophilia is relatively scarce. Understanding the progression and management of clozapine-induced eosinophilia and its end-organ effects is imperative. While there is insufficient data about the guidelines in the management of clozapine-induced eosinophilia, this study contributes to understanding the patterns of the disease progression with clozapine dosage. A case study was done on a patient with schizophrenia and autistic spectrum disorder who was on clozapine. Data on how eosinophil levels varied with clozapine dosing was analyzed and documented. The evidence of clozapine dosage affecting eosinophil and C-reactive protein levels in this patient was summarized in a table and a narrative review.

Clozapine-Induced Eosinophilia: a Case Report

INTRODUCTION

Clozapine is an atypical antipsychotic drug eligible for treatment-resistant schizophrenia. It frequently represents the best and the only choice in resistant schizophrenia. However, its use is feared by many professionals due to its possible adverse effects, such as eosinophilia.

CASE REPORT

We report a case of a young white male suffering from treatment-resistant schizophrenia who rapidly developed eosinophilia after starting clozapine.

DISCUSSION

We present a case of a 26-year-old white man diagnosed with schizophrenia with poor clinical response to several antipsychotics owing to which clozapine was started. Psychotic symptoms improved dramatically but a progressively ascendant eosinophilia was reported during serial haematological analyses. The patient remained physically asymptomatic. An exhaustive assessment with ancillary diagnostic tests revealed no cause for eosinophilia. Thus, a diagnosis of clozapine-induced eosinophilia was made. The drug was discontinued and eosinophil count progressively returned to normal but psychotic symptoms worsened.

CONCLUSIONS

Clozapine treatment is frequently feared due to its possible side effects and complications, delaying its use in refractory schizophrenia. Also, to our knowledge, there are no specific guidelines on how to manage haematological side effects such as eosinophilia. This is problematic as, in some cases, it may lead to an unnecessary withdrawal of clozapine with a worsening of psychotic symptoms. We present a brief discussion of the recent literature on the subject.

Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia

Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.

Clozapine-Induced Eosinophilia: a Case Report

INTRODUCTION

Clozapine is an atypical antipsychotic drug eligible for treatment-resistant schizophrenia. It frequently represents the best and the only choice in resistant schizophrenia. However, its use is feared by many professionals due to its possible adverse effects, such as eosinophilia.

CASE REPORT

We report a case of a young white male suffering from treatment-resistant schizophrenia who rapidly developed eosinophilia after starting clozapine.

DISCUSSION

We present a case of a 26-year-old white man diagnosed with schizophrenia with poor clinical response to several antipsychotics owing to which clozapine was started. Psychotic symptoms improved dramatically but a progressively ascendant eosinophilia was reported during serial haematological analyses. The patient remained physically asymptomatic. An exhaustive assessment with ancillary diagnostic tests revealed no cause for eosinophilia. Thus, a diagnosis of clozapine-induced eosinophilia was made. The drug was discontinued and eosinophil count progressively returned to normal but psychotic symptoms worsened.

CONCLUSIONS

Clozapine treatment is frequently feared due to its possible side effects and complications, delaying its use in refractory schizophrenia. Also, to our knowledge, there are no specific guidelines on how to manage haematological side effects such as eosinophilia. This is problematic as, in some cases, it may lead to an unnecessary withdrawal of clozapine with a worsening of psychotic symptoms. We present a brief discussion of the recent literature on the subject.

Clozapine-associated severe eosinophilia following lithium rebound neutropenia: A case report

Background

Clozapine use is complicated by an increased risk of hematological adverse effects such as neutropenia and, rarely, eosinophilia.

Case presentation

We present the case of a 48‐year‐old man with treatment‐resistant schizophrenia. On day 12 after clozapine initiation, he had a cough with a temperature of 39.8°C. On day 16, his leukocyte count had increased to 9320 cells/mm³ (neutrophils 7550 cells/mm³ and eosinophils 680 cells/mm³). We discontinued lithium because of neutrophilia and damage to renal function on day 20. His eosinophil count increased until day 29, reaching 6750 cells/mm³. We suspected a drug‐induced reaction and discontinued clozapine on day 30. His eosinophil count gradually decreased, reaching the normal range by day 40. However, his leukocyte and neutrophil counts also gradually decreased to below than the normal range by day 40. His leukocytes and neutrophil counts had recovered by day 55.

Conclusion

We concluded that this patient had clozapine‐associated severe eosinophilia following lithium rebound neutropenia.

The eosinophil count increased reaching 6750 cells/mm³ with bronchitis and hepatitis during clozapine treatment. The leukocyte and neutrophil counts gradually decreased to below than the normal range by day 40 after discontinuation of lithium.

Clozapine Rechallenge After Major Adverse Effects: Clinical Guidelines Based on 259 Cases

BACKGROUND

Clozapine is widely prescribed for treatment-refractory schizophrenia, but its use is limited by many potentially life-threatening adverse effects. The risk of rechallenge after these complications has never been comprehensively assessed in controlled studies. Thus, clinical guidelines must rely on the published case reports. The number of such reports is likely to increase over time, and updated analyses of larger samples are needed, as they may lead to changes in clinical guidelines.

STUDY QUESTIONS

How safe is the clozapine rechallenge after life-threatening adverse effects?

STUDY DESIGN

The published case reports of clozapine rechallenge were identified in a MEDLINE search. We added 121 cases reported from 2012 through 2017 to the 138 cases reported from 1972 through 2011 analyzed by us in a previous publication. The 95% confidence intervals (CIs) of the successful rechallenge rate were calculated for each adverse effect with at least 5 published case reports. The rechallenge was considered a valid clinical option when the lower end of the CI range was at least 50%.

RESULTS

A successful outcome was documented in 128/203 patients rechallenged after neutropenia (63.0%, CI, 56.0%-69.6%), 3/17 after agranulocytosis (17.7%, CI, 4.7%-44.2%), 11/17 after myocarditis (64.7%, CI, 38.6%-84.7%), and 7/7 after neuroleptic malignant syndrome (100%, CI, 56.1%-100%). Among the 15 patients with other clozapine-induced adverse effects, the rechallenge was successful in those with eosinophilia, cardiac complications other than myocarditis (QTc prolongation, pericarditis, cardiomyopathy, and atrial flutter), and gastrointestinal hypomotility. The rechallenge failed in patients who had developed pancreatitis or renal insufficiency.

CONCLUSION

Clozapine rechallenge is a reasonable clinical option after return to baseline for patients who had developed neutropenia and neuroleptic malignant syndrome, but not after agranulocytosis or myocarditis. Data are insufficient to formulate rechallenge guidelines for any other clozapine-related adverse effects.