Clozapine-induced myocarditis

Purpose
Presentation of the current state of knowledge on the epidemiology, pathogenesis, clinical picture, diagnosis and treatment of clozapine-induced myocarditis (CIM).

Views
Clozapine is widely used in patients with psychotic disorders for whom previous therapy was inadequate or not tolerated. However, in some cases its use may be associated with serious side-effects. In addition to agranulocytosis, ketoacidosis and intestinal obstruction, CIM is the most serious and potentially life-threatening complication of clozapine therapy, as it encompasses the inflammation and injury of the heart muscle. Attempts to estimate the incidence of CIM are characterized by a large discrepancy of results. To date, the pathomechanism of CIM has not been well investigated. The variability of the clinical spectrum and the lack of pathognomonic signs significantly hinder diagnosis, which is usually based on clinical symptoms, echocardiography, concentration of troponin and C-reactive protein in the serum samples and, in some cases, by myocardial biopsy and cardiac magnetic resonance imaging. In patients with suspected/confirmed CIM, the main recommendation is to discontinue clozapine and monitor the patient’s vital signs. Clinical observations indicate that a β-blocker and/or angiotensin-converting enzyme inhibitor might be useful in at least same cases of CIM.

Conclusions
We point out that patients receiving clozapine should be carefully monitored for the symptoms of CIM. The publication contains guidelines for dealing with suspected CIM.