Clozapine-associated renal failure: A case report and literature review

Electric Shock Sensation and Recurrent Falls as a Side Effect of Clozapine Therapy: A Case Report

Clozapine is an atypical antipsychotic that acts by blocking mainly dopamine 4 receptors. It is usually prescribed for treatment-resistant schizophrenia as well as treatment-resistant bipolar disorder. Clozapine has a wide profile of side effects that result from blocking different receptors all over the body. A 42-year-old Middle Eastern female is known to have suffered from schizoaffective disorder for many years and had frequent relapses despite compliance with treatment. She was commenced on Clozapine; the patient started complaining of an electric shock sensation throughout her body that resulted in recurrent falls with bilateral leg fractures. She was started on sodium valproate to exclude the possibility of seizure activity but the electric shock sensation did not subside. The decision was made to switch her to aripiprazole and gradually taper down and stop Clozapine which improved her symptoms. Careful monitoring of patients who receive Clozapine is recommended especially during the tapering phase due to the risky adverse events it can bring about. It is essential to understand the side effects in order to tackle them as soon as they arise.

Involvement of Extracellular Vesicles in the Proinflammatory Response to Clozapine: Implications for Clozapine-Induced Agranulocytosis

Most idiosyncratic drug reactions (IDRs) appear to be immune-mediated, but mechanistic events preceding severe reaction onset remain poorly defined. Damage-associated molecular patterns (DAMPs) may contribute to both innate and adaptive immune phases of IDRs, and changes in extracellular vesicle (EV) cargo have been detected post-exposure to several IDR-associated drugs. To explore the hypothesis that EVs are also a source of DAMPs in the induction of the immune response preceding drug-induced agranulocytosis, the proteome and immunogenicity of clozapine- (agranulocytosis-associated drug) and olanzapine- (non-agranulocytosis-associated drug) exposed EVs were compared in two preclinical models: THP-1 macrophages and Sprague-Dawley rats. Compared with olanzapine, clozapine induced a greater increase in the concentration of EVs enriched from both cell culture media and rat serum. Moreover, treatment of drug-naïve THP-1 cells with clozapine-exposed EVs induced an inflammasome-dependent response, supporting a potential role for EVs in immune activation. Proteomic and bioinformatic analyses demonstrated an increased number of differentially expressed proteins with clozapine that were enriched in pathways related to inflammation, myeloid cell chemotaxis, wounding, transforming growth factor-β signaling, and negative regulation of stimuli response. These data indicate that, although clozapine and olanzapine exposure both alter the protein cargo of EVs, clozapine-exposed EVs carry mediators that exhibit significantly greater immunogenicity. Ultimately, this supports the working hypothesis that drugs associated with a risk of IDRs induce cell stress, release of proinflammatory mediators, and early immune activation that precedes severe reaction onset. Further studies characterizing EVs may elucidate biomarkers that predict IDR risk during development of drug candidates. SIGNIFICANCE STATEMENT: This work demonstrates that clozapine, an idiosyncratic drug-induced agranulocytosis (IDIAG)-associated drug, but not olanzapine, a safer structural analogue, induces an acute proinflammatory response and increases extracellular vesicle (EV) release in two preclinical models. Moreover, clozapine-exposed EVs are more immunogenic, as measured by their ability to activate inflammasomes, and contain more differentially expressed proteins, highlighting a novel role for EVs during the early immune response to clozapine and enhancing our mechanistic understanding of IDIAG and other idiosyncratic reactions.

Considerations of HLA, Renal Failure, Valproic Acid Use, and Current Treatment Guidelines in Clozapine-Induced Agranulocytosis

Clozapine, the choice atypical antipsychotic for refractory schizophrenia, schizoaffective disorder, and bipolar disorder, has been shown to reduce positive and negative symptoms of schizophrenia. Clozapine, though beneficial in reducing the need for hospitalization, rehabilitation, and health care costs, is known as a drug of last resort due to its potential adverse event of clozapine-induced agranulocytosis, which holds a case fatality rate between 4.2 and 16%. Herein, we describe a female patient with longstanding schizoaffective disorder and chronic kidney disease who suffered from clozapine-induced agranulocytosis after failing two other atypical antipsychotics. Retrospective considerations of this case and management highlight risk factors such as HLA status, renal failure, and concurrent valproic acid use which presently do not have official screening, guidelines, or restrictions in place when prescribing clozapine. Additionally, there are no specific clozapine-induced agranulocytosis management recommendations such as G-CSF/filgrastim dose, timing of bone marrow aspirate and biopsy, and use of concomitant valproate. We propose that further comprehensive official screening, monitoring, and guidelines in the prescribing of clozapine, and further guidelines in the treatment of clozapine induced agranulocytosis, could increase the cost-effectiveness of clozapine treatment, and decrease the incidence, and morbidity of this feared adverse event.