Edema and erythema at the IV insertion site suggests the IV has extravasated. The nurse should first stop the infusion of vancomycin. Once the infusion is stopped, the nurse should aspirate the cannula followed by drainage of any palpable fluid collections to remove the damaging medication from the tissue. Slowing the infusion rate is appropriate for the management of red man syndrome, which is associated with vancomycin, but it is not appropriate to treat this patient.