To provide immediate protection from hepatitis B infection, what medication should the nurse administer to a patient who shared needles?

Administering gamma globulin, also known as hepatitis B immunoglobulin (HBIG), provides immediate passive immunity to hepatitis B virus (HBV) for someone who has potentially been exposed to the virus, such as through needle sharing. This medication contains antibodies that can neutralize the virus and prevent its replication in the body, thus offering rapid protection.

This immediate action is particularly important in post-exposure situations because the onset of the disease can be very quick and severe. While vaccination against hepatitis B is critical and effective for long-term immunity, it requires time for the immune response to develop and does not provide immediate protection.

Corticosteroids do not directly aid in preventing hepatitis B infections; instead, they are typically used to reduce inflammation and modify the immune response in various conditions. Fresh frozen plasma is used in cases of clotting disorders and does not contain the specific antibodies needed to provide protection against HBV.

Thus, in the context of immediate exposure to HBV, the appropriate intervention is administering gamma globulin, as it supplies the necessary antibodies right away.