Get our free Filgrastim coupon and be eligible to receive a discount. You can reduce your Filgrastim cost by up to 75% with our free Filgrastim discount card. Bring it to a participating pharmacy near you to save on your prescription medication.Filgrastim is a man-made form of a protein that stimulates the growth of white blood cells in your body. White blood cells help your body fight against infection. Filgrastim is used to treat neutropenia, a lack of certain white blood cells caused by cancer, bone marrow transplant, receiving chemotherapy, or by other conditions. Filgrastim may also be used for purposes not listed in this medication guide.