This class contains information about a Pharmacy Order, commonly referred to as a prescription. This class represents the prescription from the perspective of the filling system (i.e., the pharmacy) whereas the Pharmacy Request represents the prescription from the ordering system (i.e., the prescriber). This class is a subtype of the more general Healthcare Promise, which describes properties common to all types or Orders from the filling system perspective– this class adds those properties which are specific to medication orders. This class is called Pharmacy Promise rather than Pharmacy Order following the HL7 V3 convention to use the term Promise to indicate that it is from the filling system’s perspective. There are many properties which are identical to the Order; this is because the pharmacy may change the order, within prescribed limits, for example substituting a generic drug for a brand-named one.