A CASE REPORT OF CLOZAPINE-INDUCED MYOCARDITIS IN A 27-YEAR- OLD SCHIZOPHRENIA PATIENT
Authors: Noh *Jaisung , Ryu Hankyel 
Published: February 2025

Abstract

Introduction
Clozapine is known as one of the atypical antipsychotic drugs with fewer extrapyramidal side effects. Its therapeutic effects have been well-established through various studies. We reported a case of myocarditis in a 36-year-old male patient with schizophrenia in 2012 [1]. In this paper, we report another case of myocarditis that occurred during Clozapine treatment in a 27-year-old patient with schizophrenia, aiming to raise awareness about the occurrence of myocarditis.

Case Report
The patient was a 27-year-old single man who had been admitted to the Department of Psychiatry at our hospital in due to auditory hallucinations and delusions. Due to the lack of symptom improvement even after trying different medications and doses, the patient was admitted to our hospital for further evaluation and treatment. The patient's Clozapine dosage was increased up to 100mg on the 8th day of application. On the 9th day of Clozapine administration with a dosage of 150mg, the patient experienced a fever of 38.4 degrees Celsius for the first time. On the subsequent days of fever confirmation, the test results showed Total IgE at 508 KU/L and Eosinophil count at 200. On the 12th day of Clozapine administration, the CRP level increased to 5.53, and Troponin T was elevated for the first time (0.031 ng/mL). The results of Total IgE, obtained on the day of Clozapine discontinuation, showed an increase to 649 KU/L, and Eosinophil count was 100 (Fig. 2). Considering the possibility of Clozapine-induced myocarditis, Clozapine was discontinued on the 13th day of administration, and Olanzapine 5mg was initiated. To further evaluate the patient, transthoracic echocardiography, chest CT, and abdomen CT were performed on the day of Clozapine discontinuation. Minimal pericardial effusion was observed on echocardiography, but the left ventricular contraction ability was good. Chest CT also showed tiny pericardial effusion. Consultation with a cardiologist revealed no abnormalities in cardiac structure and function, and a follow-up echocardiogram was recommended after one week. On the 7th day after Clozapine discontinuation, Troponin T levels had returned to a normal range (&lt;0.013 ng/mL). On the 9th day of discontinuation, CRP levels had improved to 0.43 mg/dL. Although the Cardiac marker and CRP levels improved and returned to normal range, there was a persistent increase in Eosinophil count and Total IgE levels. As a result, an additional consultation with an allergist was conducted. Methylprednisolone was also administered. After the application of Methylprednisolone, follow-up blood tests showed that Eosinophil count had returned to normal levels, and there was a noticeable decrease in IgE levels.

Discussion And Conclusion
We experienced a case of myocarditis during Clozapine treatment in a 27- year-old patient with schizophrenia. The mechanism of Clozapine-induced myocarditis is not entirely understood, but it has been suggested that eosinophil infiltration with IgE-mediated acute hypersensitivity reactions may be involved [2]. In the event of switching medication due to Clozapine- induced myocarditis, careful drug selection and close monitoring are necessary to avoid exacerbating adverse reactions.

References
1.Jo, W.D., B.-J. Choi, and J.S. Noh, A Case of Clozapine-Induced Myocarditis. Korean Journal of Biological Psychiatry, 2012. 19(3).
2.Kilian, J.G., et al., Myocarditis and cardiomyopathy associated with clozapine. The Lancet, 1999. 354 (9193): p. 1841-1845.