Filgrastim injection products (Granix, Neupogen, Nivestym, Zarxio) are used to decrease the chance of infection in people who have non myeloid cancer (cancer that does not involve the bone marrow) and are receiving chemotherapy medications that may decrease the number of neutrophils (a type of blood cell needed to fight infection). Filgrastim injection products (Neupogen, Nivestym, Zarxio) are also used to help increase the number of white blood cells, and decrease the length of time with fever in people with acute myeloid leukemia (AML; a type of cancer of the white blood cells) who are receiving treatment with chemotherapy medications. Filgrastim injection products (Neupogen, Nivestym, Zarxio) are also used in people who are undergoing bone marrow transplants. Filgrastim is in a class of medications called colony-stimulating factors.