<p>Filgrastim is a granulocyte-colony stimulating factor which binds to cell surface receptors on haemetopoietic cells thus stimulating the development of granulocytes to increase their migration and cytotoxicity.<br />
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Filgrastim is a glycoprotein which regulates the production and release of functional neutrophils from the bone marrow. Filgrastim causes marked increases in peripheral blood neutrophil counts within 24 hours, with minor increases in monocytes. Elevations of neutrophil counts are dose-dependent at recommended doses. Following termination of Filgrastim therapy, circulating neutrophil counts decrease by 50% within 1 to 2 days, and to normal levels within 1 to 7 days.</p>