Clozapine is an atypical antipsychotic used for treatment resistant schizophrenia. Its potential to induce agranulocytosis is well known but it can also cause myocarditis. Clozapine is the only antipsychotic known to induce this side effect, typically early in the treatment, and literature is scarce on this condition. We are presenting a case report of a 21-year-old schizophrenic male who developed myocarditis within 3 weeks of starting on clozapine for his treatment resistant psychosis. We then aim to review some of the available literature and raise awareness among physicians as this condition can potentially be fatal if not detected early. 1. Introduction We are presenting the case of a 21-year-old male with 2 years of ongoing psychotic symptoms not responsive to several trials of medication. He was started on clozapine and developed myocarditis on the 23rd day after initiation of treatment. Clozapine is a tricyclic dibenzodiazepine derivative classified as an atypical antipsychotic. It is the treatment of choice for treatment resistant schizophrenia, defined as a lack of response to at least two antipsychotics after a trial of 6–8 weeks. Its advantages include low risk of extra pyramidal symptoms (EPS) and it has been shown to significantly reduce suicidal behaviour in patients with schizophrenia. In terms of side effects, agranulocytosis and neutropenia are frequently recognized as serious ones and there are elaborate protocols to monitor and manage these. Cardiac side effects, including myocarditis, are perceived to be a more rare complication and there are currently no monitoring protocols. According to reports, more than 85% of the cases occur in the first 2 months and up to 75% within 3 weeks [1]. Myocarditis is an inflammation of the myocardium causing myocyte injury and can result in heart failure. Myocarditis is most often of viral etiology but it is also induced by several drugs and can be due to an autoimmune disorder [2]. Little is known about the pathophysiology of clozapine-induced myocarditis, but the mechanism is postulated to be a type 1 hypersensitivity reaction [3]. This condition has a variety of presenting symptoms. Many cases have a nonspecific “flu-like” presentation, including fever, shortness of breath, dry cough, and an elevated WBC [4]. There is frequently overlap with some symptoms of the “classic” hypersensitivity reaction, including fever, peripheral eosinophilia, sinus tachycardia, and a rash [2, 5]. However, there is no “classical” presentation of clozapine-induced myocarditis. Several authors have compiled tables of
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