Q: What is the difference between filgrastim (Neupogen) and pegfilgrastim (Neulasta)?


Answer:

Filgrastim (Neupogen): is a granulocyte colony-stimulating factor (G-CSF) analog used to stimulate the proliferation and differentiation of granulocytes in neutropenic patients. It can be given subcutaneously or intravenously. Usual dose is 5 mcg per kg of weight daily.

Pegfilgrastim (Neulasta): When compared to filgrastim, pegfilgrastim has an added polyethylene glycol molecule which reduces renal clearance and prolongs persistence in vivo (half life range: 46-62 hours). Pegfilgrastim can be given on the first day of chemotherapy.The effects of one dose of pegfilgrastim last fourteen days. It can only be given subcutaneously and not intravenously. The recommended dosage is a single subcutaneous injection of 6 mg administered once per chemotherapy cycle.