Is Clozapine Useful in Schizophrenic Patients with Concomitant Chronic Inflammatory Disease?

Introduction

In terms of side effects affecting the hematological system, clozapine is best known for its propensity to cause severe leukopenia and agranulocytosis [1]. Hematological dysfunction in the course of clozapine treatment can be either a direct effect of the drug or a sign of various medical disorders unrelated to clozapine. Leukocytosis, for instance, can be either a side effect of clozapine or an indicator for a concomitant infection. Leukopenia, on the other hand, may be found as a harmless, often transient phenomenon, as well as an early sign of incipient agranulocytosis. Effects of other drugs used concurrently with clozapine and the possibility of laboratory errors should also be considered. Previous studies have differentiated between transient “benign” neutropenia, recurrent transient neutropenia, and progressive neutropenia [2] [3] [4].Transient neutropenia is a disorder in which neutrophil granulocytes drop below a defined value, but return to normal values with continued clozapine treatment. Plasma levels of clozapine do not correlate to any of the hematological disorders described above [5]. However, a recent report suggested that N-desmethylclozapine, the major metabolite of clozapine, is associated with bone marrow toxicity comparable to carbamazepine [6].

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