A record of a medication that is being consumed by a patient. A MedicationUsage may indicate that the patient may be taking the medication now or has taken the medication in the past or will be taking the medication in the future. The source of this information can be the patient, significant other (such as a family member or spouse), or a clinician. A common scenario where this information is captured is during the history taking process during a patient visit or stay. The medication information may come from sources such as the patient's memory, from a prescription bottle, or from a list of medications the patient, clinician or other party maintains.

The primary difference between a medicationusage and a medicationadministration is that the medication administration has complete administration information and is based on actual administration information from the person who administered the medication. A medicationusage is often, if not always, less specific. There is no required date/time when the medication was administered, in fact we only know that a source has reported the patient is taking this medication, where details such as time, quantity, or rate or even medication product may be incomplete or missing or less precise. As stated earlier, the Medication Usage information may come from the patient's memory, from a prescription bottle or from a list of medications the patient, clinician or other party maintains. Medication administration is more formal and is not missing detailed information.

The MedicationUsage resource was previously called MedicationStatement.

Identifiers associated with this Medication Usage that are defined by business processes and/or used to refer to it when a direct URL reference to the resource itself is not appropriate. They are business identifiers assigned to this resource by the performer or other systems and remain constant as the resource is updated and propagates from server to server.

This is a business identifier, not a resource identifier.

A larger event of which this particular MedicationUsage is a component or step.

A code representing the status of recording the medication usage.

This status concerns just the recording of the medication usage. MedicationUsage.adherence should be used for indicating a patient's adherence to the information in this resource. Note, the statuses are different than in previous releases for MedicationUsage or MedicationStatement.

This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

Type of medication usage (for example, drug classification like ATC, where meds would be administered, legal category of the medication.).

Identifies the medication being administered. This is either a link to a resource representing the details of the medication or a simple attribute carrying a code that identifies the medication from a known list of medications.

If only a code is specified, then it needs to be a code for a specific product. If more information is required, then the use of the medication resource is recommended. For example, if you require form or lot number, then you must reference the Medication resource.

The person, animal or group who is/was taking the medication.

The encounter that establishes the context for this MedicationUsage.

The interval of time during which it is being asserted that the patient is/was/will be taking the medication (or was not taking, when the MedicationUsage.adherence element is Not Taking).

This attribute reflects the period over which the patient consumed the medication and is expected to be populated on the majority of Medication Usages. If the medication is still being taken and is expected to continue indefinitely at the time the usage is recorded, the "end" date will be omitted. If the end date is known, then it is included as the "end date". The date/time attribute supports a variety of dates - year, year/month and exact date. If something more than this is required, this should be conveyed as text.

The date when the Medication Usage was asserted by the information source.

The person or organization that provided the information about the taking of this medication. Note: Use derivedFrom when a MedicationUsage is derived from other resources, e.g. Claim or MedicationRequest.

Allows linking the MedicationUsage to the underlying MedicationRequest, or to other information that supports or is used to derive the MedicationUsage.

Likely references would be to MedicationRequest, MedicationDispense, Claim, Observation or QuestionnaireAnswers. The most common use cases for deriving a MedicationUsage comes from creating a MedicationUsage from a MedicationRequest or from a lab observation or a claim. it should be noted that the amount of information that is available varies from the type resource that you derive the MedicationUsage from.

A concept, Condition or observation that supports why the medication is being/was taken.

This could be a diagnosis code. If a full condition record exists or additional detail is needed, use reasonForUseReference.

Provides extra information about the Medication Usage that is not conveyed by the other attributes.

Link to information that is relevant to a medication usage, for example, illicit drug use, gestational age, etc.

The full representation of the dose of the medication included in all dosage instructions. To be used when multiple dosage instructions are included to represent complex dosing such as increasing or tapering doses.

The content of the renderedDosageInstructions must not be different than the dose represented in the dosageInstruction content.

Indicates how the medication is/was or should be taken by the patient.

The dates included in the dosage on a Medication Usage reflect the dates for a given dose. For example, "from November 1, 2016 to November 3, 2016, take one tablet daily and from November 4, 2016 to November 7, 2016, take two tablets daily." It is expected that this specificity may only be populated where the patient brings in their labeled container or where the Medication Usage is derived from a MedicationRequest.

Indicates if the medication is being consumed or administered as instructed.

Type of the adherence for the medication.

Captures the reason for the current use or adherence of a medication.

This is generally only used for "exception" statuses such as "entered-in-error". The reason for performing the event at all is captured in reasonCode, not here.