A drug used before autologous stem cell transplantation in patients with non-Hodgkin lymphoma or multiple myeloma. Plerixafor is given together with granulocyte-colony stimulating factor (G-CSF) to help move stem cells from the bone marrow to the blood. The stem cells can then be collected, stored, and given back to the patient. Plerixafor is a type of chemokine receptor antagonist. Also called AMD 3100 and Mozobil.