Abstract
To the Editor
Neutropenia associated with atypical antipsychotics other than clozapine is rare in clinical practice (Stübner et al., 2004). We report a case of neutropenia which occurred early during treatment with lurasidone, which has been marketed recently for the treatment of schizophrenia and bipolar disorder.
A 49-year-old Caucasian woman presented for review at our community mental health service following remission of a manic episode. Although stable on a combination of asenapine 20 mg and valproate 1 g daily for 2 months, complaints of unpleasant taste and significant weight gain prompted change from asenapine to lurasidone at a dose of 40 mg. Seven weeks later, a decline in the white cell count (WCC) to 3.5 × 109/L from the previous level of 4.4 × 109/L was observed. This declined further to 2.9 × 109/L with a neutrophil count of 1.6 × 109/L (reference range: 1.8–7.5 × 109/L). Lurasidone was immediately ceased, but valproate was continued. Within a week, the counts returned to the normal range. Monthly monitoring for 6 months confirmed that the values remained stable and the patient stayed well.
Neutropenia associated with lurasidone has not been reported previously. Widely different incidence of neutropenia with atypical antipsychotics ranging from 0.05% in retrospective studies (Stübner et al., 2004) to 17.6% in prospective studies (Rettenbacher et al., 2010) has been described. While the pathophysiology of this condition remains uncertain, direct toxic effects on haematopoiesis, immunological reaction and genetic factors have been proposed as relevant (Stübner et al., 2004). Concomitant prescription of antiepileptic drugs can elevate risk of neutropenia (De Leon et al., 2012). However, in this case, the temporality of the event with lurasidone and its resolution diminished the possible role of another agent. Some authors have suggested that neutropenia associated with atypical antipsychotics is transient and does not progress to agranulocytosis and caution against medication discontinuation following a single pathological WCC (Rettenbacher et al., 2010). Nevertheless, when initiating treatment with atypical antipsychotics monitoring of WCC and neutrophils is prudent and should become an integral component of good clinical practice.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.