503A Pharmacy
A traditional compounding pharmacy operating under Section 503A of the US Federal Food, Drug, and Cosmetic Act that prepares customised medications based on individual patient prescriptions. 503A pharmacies are primarily regulated by state boards of pharmacy and are exempt from FDA pre-market approval.
Technical Context
503A exemption conditions: the pharmacy compounds based on individual prescriptions from licensed practitioners, does not compound 'regular or inordinate' amounts in anticipation of prescriptions, does not sell compounds across state lines (limited exceptions exist), uses ingredients from FDA-registered suppliers meeting USP/NF compendial standards, and does not compound drugs that are 'essentially a copy' of a commercially available product (unless the prescriber documents a clinical difference). State boards of pharmacy are the primary regulators — oversight quality varies significantly between states. The FDA can intervene when 503A pharmacies exceed their exemption boundaries (e.g. producing bulk quantities without prescriptions, selling interstate). Patient harm incidents from poorly compounded products have driven calls for more consistent oversight.