Neupogen (generic: filgrastim) is a prescription medication used to reduce the risk of infection in people with some tumors receiving strong chemotherapy that decreases the number of infection-fighting white blood cells known as neutrophils. Neupogen belongs to a group of drugs called colony stimulating factors, which stimulate the body to produce neutrophils.

This medication comes in an injectable form that is given just under the skin or directly into a vein (IV), usually once a day.

Common side effects of Neupogen include bone pain and muscle pain.