Update the comments to make it clear that the precondition might not be specific to "?"Take 'as needed'; Or take for specific condition (precondition)" Change precondition in the description and comments from the existing 'pre-condition'. August 28, 2015: Update Definition and constraints on MedicationOrder.dosageInstruction.asNeeded on MedicationOrder, MedicationDispense and MedicationAdministration to: Indicates whether the Medication is only taken when needed within a specific dosing schedule (Boolean option), or it indicates the precondition for taking the Medication (CodeableConcept). Specifically if 'boolean' datatype is selected, then the following logic applies: If set to True, this indicates that the medication is only taken when needed, within the specified schedule. Update CodeableConcept: "MedicationAsNeededReason" binding to: "A coded concept identifying the precondition that should be met or evaluated prior to consuming or administering a medication dose. For example "pain", "30 minutes prior to sexual intercourse", "on flare-up", etc." August 30, 2015: will investigate adding precondition for as needed and other use cases on all relevant Pharmacy resources as a future enhancement. New tracker item will be added.