Items (prescription items).
One item is one product on one prescription form, dispensed once. It is the unit of NHS prescribing volume, and it is not a patient.
An item is the basic unit of prescribing volume: one product appearing on one prescription form, dispensed once. A patient collecting a monthly repeat generates about 12 items a year for that medicine. Two strengths on one form count as two items.
Nearly every chart of NHS prescribing you have seen is a chart of items. Items are honest about workload and direction of travel, and silent about patient numbers, doses and adherence. When items rise 10%, that could be more patients, longer prescriptions or shorter gaps between collections. The distinction has sunk more than one market-share slide.
Quantity · The units dispensed within an item: tablets, millilitres, grams. Useful, and easy to aggregate into nonsense.
English Prescribing Data (EPD) · The monthly NHSBSA dataset behind almost every NHS prescribing chart: every item dispensed in the community in England, by practice and presentation.
Defined daily dose (DDD) · The WHO's assumed average adult maintenance dose, used to compare prescribing volumes across drugs and strengths.
See it on a real molecule.
Every molecule page uses this term somewhere: in the scorecard, the charts or the honesty strip. The definitions live here; the numbers live there.