I am disturbed by the renaming of MedicationStatement to MedicationUsage. While it's technically permissable, this is a resource that's had plenty of implementation experience, and feedback from the implementers is that this is not a value proposition. However renaming a resource is less of a problem than the changes to the status codes. In effect the status codes have been changed from the implied status of the medication to the actual status of the medication usage statement.

If that's the case, there should at least be a 'draft' status or similar to support workflows around editing and making medication usage statements. I'm also disturbed by the removal of computable support for 'not-taking'; I believe that this is an important statement to make. Nor do I see computable support for 'no longer taking', other than with a period, and it is likely that no precise end date is available but there is certainty that the medication is no longer being taken. Further, given the imprecise semantics, I don't know what the use of effectiveDateTime is: is/was/will be - that's the status I'm missing: is/was/will be