What does Neulasta contain?

Neulasta contains pegfilgrastim, which is a long-acting form of granulocyte-colony stimulating factor (G-CSF). Pegfilgrastim is designed to stimulate the production of neutrophils in the bone marrow, enhancing the body's ability to fight infections, especially after chemotherapy. This medication is used primarily in cancer patients to reduce the risk of neutropenia (a decrease in white blood cells).

In contrast, other options such as neutrophils refer to the actual white blood cells produced as a response to pegfilgrastim, and epoetin alfa is a medication used to stimulate red blood cell production. Lansoprazole is a proton pump inhibitor used for treating gastrointestinal issues, and is unrelated to the function or composition of Neulasta. Therefore, pegfilgrastim is the correct answer as it directly represents the active ingredient in Neulasta that performs critical functions in managing side effects of cancer treatment.