“Mr. N,” a man in his mid-50s, was diagnosed with paranoid schizophrenia in his early 20s. He had never received clozapine, but he had been taking fluphenazine, 50 mg i.m every 2 weeks, for 20 years when he was initially noted neutropenic in 2003 (Figure 1). In 2004, the neutropenia worsened with the introduction of olanzapine, 10 mg/day, dropping to 500 neutrophils/μl. At this point, both antipsychotics were discontinued and he was started on haloperidol, 5 mg/day. In early 2006, he was switched to flupenthixol, 40 mg i.m every 2 weeks. Mr. N’s absolute neutrophil count dropped to 200/μl, and he was subsequently switched back to fluphenazine (range, 20–60 mg every 2 weeks) late in that same year. In fall 2012, he was admitted as a result of a psychosis exacerbation thought to be related to noncompliance of antipsychotic therapy. On admission, his absolute neutrophil count was noted as 2,100/μl, and this dropped to 400/μl after switching to paliperidone (156 mg every 4 weeks, maintenance dosage). Of note, this pattern had been documented on two prior admissions that were caused by noncompliance followed by acute psychotic exacerbations (Figure 1). The treatment plan included maintaining paliperidone at the lowest dosage possible that would prevent psychosis.
FIGURE 1.Absolute Neutrophil Count Over Time and Correspondence to Antipsychotic Treatment and Admissions Due to Noncompliance
A bone marrow biopsy in February 2006, when Mr. N’s absolute neutrophil count was 300/μl, revealed normal cellularity on the three lines, with adequate white cell precursors and good white cell differentiation, indicating no bone marrow disorder. He was human leukocyte antigen (HLA) II genotyped, showing a DQB1*06 genotype (DRB1*15, DRB1*16, and DQB1*05 were all absent). Over 10 years of follow-up, Mr. N. has never presented with any infectious complication from low absolute neutrophil count or required treatment with granulocyte colony-stimulating factor.