An analysis of current prescribing practices in a community hospital: Filgrastim used to prevent and treat febrile neutropenia, a potentially dangerous side effect of myelosuppressive chemotherapy

Purpose: Currently, Huntington Hospital lacks a protocol for the use of filgrastim for prophylaxis and treatment of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy. Therefore, the primary objective of this medication utilization evaluation was to assess current prescribing practice. The secondary objective was to utilize findings to make a recommendation for a drug protocol.  [56]

Methods: Patients who received filgrastim within the respective period (Feb-Apr 2012) were compiled using Horizon Meds Manager. Records were reviewed retrospectively and data, including prescribing specialty, patient’s admission weight, day of the last chemotherapy, filgrastim dose/frequency/duration/indication, pre-treatment temperature, white blood count and neutrophil percent count, if available, was assembled using Microsoft Excel 2010. Using the data collected, filgrastim daily dose of 5 mcg/kg and absolute neutrophil count were calculated. [68]

Results: Records of eighteen patients were reviewed.  The majority (73%) of the orders were written by hematologists/oncologists.  Four patients were excluded because: outpatient order (n=1), FN induced by non-chemotherapeutics (n=2), inadvertent administration while on pegfilgrastim (n=1).  Fourteen patients (78%) received filgrastim for neutropenia due to myelosuppressive chemotherapy. There was a 20% difference between the calculated dose and actual administered in four (29%) patients.   Half of them received filgrastim 480mcg and for the other two the calculated dose of 397mcg was rounded off to a dose of 300mcg.  The majority (92%) of patients received filgrastim 24-72 hours post-chemotherapy  with the exception of one. [103]

Conclusions: These findings identified two areas of opportunity to optimize filgrastim dosing in the setting of myelotoxic chemotherapy.  Rounding off the calculated dose/kg/day to the nearest vial size by institution-defined weight limits may optimize initial dose and prevent reductions in chemotherapy dose or delays in therapy.  Inappropriate filgrastim administration in the context of chemotherapy completion may compromise clinical outcomes, thus hematology-oncology consult may be warranted.  Further studies are needed to support these conclusions. [72]