Brain natriuretic peptide as a biomarker of asymptomatic clozapine-related heart dysfunction: a criterion for a more cautious administration.

Clozapine-related pericarditis is a rare side effect of the drug. We reported the clinical cases of two women, aged 22 and 28 years, affected by schizophrenia with pericarditis symptoms related to clozapine treatment of 200 mg/day. Clozapine was discontinued in both patients, resulting in normalization of the ECG changes, and echocardiography confirmed the progressive disappearance of the pericardial effusion. Interestingly, while inflammatory indices and pro-brain natriuretic peptide (pro-BNP) plasma levels were high in both patients, only one of them showed tachycardia, subjective chest pain, shortness of breath and dyspnea, with a clinical symptomatology suggesting a cardiac involvement. BNP is a vasoactive peptide synthetized by the ventricular myocardium which splits in two fragments: BNP and the N-terminal (pro-BNP). Both are considered valuable biomarkers in clinical practice for the prediction of disease state and prognosis in patients with suspected heart failure. Pro-BNP acts as a key regulator in the homeostasis of water and salt excretion and in the maintenance of blood pressure, mainly by inhibiting the renin-angiotensin-aldosterone axis and blocking the sympathetic nervous activity. In our cases, pro-BNP plasma levels proved to be a profitable way to identify subjects with asymptomatic cardiac impairment who could benefit from a therapy preventing progression to heart failure.