Late-Onset Neutropenia in Long-Term Clozapine Use and Its Management Utilizing Prophylactic G-CSF

Figure 1

Neutrophil serum level from 22nd of January to 10th of December 2018. Figure 1 displays the neutrophil level by serum testing from 22nd of January to 10th of December 2018. The axis demonstrates dates of sampling, and the axis corresponds with absolute neutrophil count (ANC) ×10⁹/L. Initially, there is a period of neutropenia (-). Filgrastim, G-CSF 30 MU, was prescribed on February 10th resulting in an ANC which increased from to one day later. A further neutropenic episode occurred on March 4th with ANC . Lithium was commenced on March 10th. Clozapine rechallenge in September corresponded with further deterioration in ANC measurements prompting close liaison with hematology to devise a filgrastim treatment protocol.