Every year, significant amounts of expensive drugs are discarded. This is due in part to the growing number of prescription drugs that are administered in variable doses (rather than fixed or flat doses) based on a patient's weight or body size. Strict regulations and guidance generally prohibit or severely restrict the acceptable time frame for sharing medication from single-dose vials among patients, and so the unused amount will typically be discarded. Due to the current system for producing, administering, and paying for drugs in the United States, significant - but indeterminate - amounts of expensive prescription drugs are discarded each year. At the request of the Centers for Medicare & Medicaid Services, Medications in Single Dose Vials: Implications of Discarded Drugs explores the federal health care costs, safety, and quality concerns associated with discarded drugs that result from the weight-based dosing of medicines contained in single-dose vials.