#filgrastim

In this article, we will discuss Filgrastim (Mechanism of Action). So, let’s get started. Mechanism of ActionColony-stimulating factors are glycoproteins which act on hematopoietic cells by binding to specific cell surface receptors and stimulating proliferation‚ differentiation commitment‚ and some end-cell functional activation. Endogenous G-CSF is a lineage-specific colony-stimulating factor…

In this article, we will discuss Filgrastim (Mechanism of Action). So, let’s get started. Mechanism of ActionColony-stimulating factors are glycoproteins which act on hematopoietic cells by binding to specific cell surface receptors and stimulating proliferation‚ differentiation commitment‚ and some end-cell functional activation. Endogenous G-CSF is a lineage-specific colony-stimulating factor…

Common Brand Names: Neupogen

Therapeutic Class: A hematopoietic growth factor which promotes proliferation and maturation of neutrophil granulocytes.

Common Injectable Dosage Forms:

Injection: 300 mcg/mL (1 mL, 1.6 mL), 600 mcg/mL (0.5 mL, 0.8 mL)

Dosage Ranges:

The recommended initial dose is 5 mcg/kg/day for up to 2 weeks or until the absolute neutrophil count reaches 10,000/mm3 for patients that are in post-antineoplastic therapy states.

In bone marrow transplantation, dosage is 10 mcg/kg/day and adjusted accordingly.

Administration and Stability: The commercially available solution (300 mcg/mL) may be given by direct rapid SQ injection. When given by IV infusion, the desired dose should be diluted with 50-100 mL of D5W to a concentration not less than 5 mcg/mL and may be given over 15-60 minutes or infused continuously over 24 hours. For continuous SQ infusion, the dose is diluted with 10-50 mL of D5W and administered at a rate not exceeding 10 mL/24 hours. When diluted to less than 15 mcg/mL, the solution should have 2 mcg/mL of albumin added to lessen the likelihood of adsorption. pH 4

Pharmacology/Pharmacokinetics: Filgrastim exerts its hematopoietic effects primarily by binding to neutrophil progenitor target cells that acts to stimulate proliferation of neutrophils within the bone marrow and possibly other sites. Following subcutaneous bolus administration, peak serum levels are observed in 2-6 hours. It is rapidly distributed with highest concentrations in the bone marrow, adrenal glands, kidney, and liver. The elimination half-life is 1.5-7 hours.

Drug and Lab Interactions: Filgrastim should not be administered within 24 hours before or after a dose of myelosuppressive antineoplastic agent. Because of transient decreases in platelet counts following filgrastim doses, caution should be used with patients on other platelet depressing agents. Lithium could theoretically potentiate the effects of filgrastim, but this has not been clinically established.

Contraindications/Precautions: Contraindicated in patients with known sensitivity to any proteins derived from E. coli. CBC and platelet counts should be performed prior to initiation and at least twice weekly during therapy to avoid the possibility of excessive leukocytosis or thrombocytopenia. Caution should be exercised in patients with suspected myeloid malignancies as tumor growth could be stimulated by filgrastim therapy. Pregnancy Category C.

Monitoring Parameters: CBC with diff., monitor for neutropenia.

Adverse Effects: The most common adverse effect is bone pain; other less common reactions include fever, elevations in serum uric acid, local cutaneous reactions, and occasionally, splenomegaly.