Filgrastim (Grafeel, Neukine) — Injections for Low White Cell Count

Grafeel and Neukine are brand names for filgrastim, a medicine that raises your white blood cell count after chemotherapy. Chemotherapy can lower the count to a level where ordinary bacteria become dangerous. Filgrastim signals your bone marrow to produce new white cells faster, shortening the period your counts stay in the high-risk range. Your oncologist will tell you how it fits into your treatment plan.

Filgrastim works by pushing the bone marrow to produce more white cells than it normally would. The marrow sits inside bone, and when it becomes very active it expands. That expansion creates pressure inside a confined space. The lower back, hips, sternum, and long bones are where most people feel it most. The pain is a sign the medicine is working, not a sign anything is going wrong.

The injection goes into fatty tissue just under the skin — not into a vein or muscle. The most common sites are the lower abdomen away from the navel, the outer thigh, and the upper arm. Your nurse will show you the correct technique, how to rotate sites so one spot does not become sore, and how to dispose of the needle safely.

Yes. Home administration is common once a family member has been shown the technique by your nurse. If you are not comfortable giving it at home, or the first dose is being given, ask whether it can be administered at the clinic. Your team will also explain how to store the medicine correctly before each dose.

No. The bone pain from filgrastim comes from the marrow responding to the medicine, not from the disease. That said, if the pain feels different from what you were warned about, is in a new location, or comes alongside fever, call your team the same day. Any new bone pain during cancer treatment deserves a conversation with your oncologist.

Tell your treating team before taking any pain medicine. Some medicines used for pain are not safe alongside cancer treatment, and your team knows your full medicine list. If the pain is severe enough that you cannot sleep or carry out daily activities, call the same day — do not wait for your next scheduled visit.

Bone pain is the most commonly reported side effect. Some people notice redness, bruising, or a small lump at the injection site, which usually settles within a day or two. A small number of people develop sudden severe pain in the upper left abdomen — this is rare but needs immediate medical attention. Report any unexpected symptoms to your team rather than assuming they are normal.

The most direct measure is a blood test showing your white cell count rising. Your oncologist will time these checks as part of your treatment plan. When the count recovers to a safe level, the injections are typically no longer needed for that cycle. The bone pain itself is a practical signal that the marrow is responding, but blood tests are what your team uses to decide next steps.