PrescriptionChangeRequest

Last updated: 2 Sep 2026

Introduction #

The PrescriptionChangeRequest model represents an incoming Surescripts (NCPDP SCRIPT) request to change a prescription — for example, a generic substitution, a prior-authorization requirement, or a script clarification. Each request carries the raw request payload in its content attribute, the medication codings that describe the drug in question (PrescriptionChangeRequestCoding), and a reference to the original prescription it relates to.

PrescriptionChangeRequest is a read-only data model. Because a request originates from the pharmacy, its patient, note, and staff associations are nullable and may be unset. The provider’s approve/deny decision is recorded as a PrescriptionChangeResponse, which links back to the request and is available through the request’s response reverse relation.

Basic usage #

To get a prescription change request by identifier, use the get method on the PrescriptionChangeRequest model manager:

from canvas_sdk.v1.data import PrescriptionChangeRequest

change_request = PrescriptionChangeRequest.objects.get(id="d2194110-5c9a-4842-8733-ef09ea5ead11")

A change request’s medication codings are available through the codings reverse relation, and the responses recorded against it are available through the response reverse relation:

from canvas_sdk.v1.data import PrescriptionChangeRequest
from logger import log

change_request = PrescriptionChangeRequest.objects.get(id="d2194110-5c9a-4842-8733-ef09ea5ead11")

for coding in change_request.codings.all():
    log.info(f"system:  {coding.system}")
    log.info(f"code:    {coding.code}")
    log.info(f"display: {coding.display}")

responses = change_request.response.all()

The PrescriptionChangeRequestCoding entries represent the coding of the medication in question (for example, FDB or RxNorm), with an unstructured fallback whose display carries the drug description text when no structured code is available.

Message content #

The message_id and content attributes carry the details of the inbound eRx message.

message_id is the eRx (NCPDP SCRIPT / Surescripts) message identifier of the inbound change request.

content is a JSON field holding the parsed inbound NCPDP SCRIPT change-request payload. It is a free-form, unstructured representation whose exact shape can vary between messages, typically including the pharmacy, the prescriber as reported by the sender, and the dispensed medication details (drug description, NDC, quantity, and similar). content defaults to an empty object ({}), so it is safe to call .get() on, but individual keys may be absent — plugins should access it defensively.

Change types #

The type_code attribute identifies the kind of change the pharmacy is requesting:

Code	Description
G	Generic Substitution
P	Prior Authorization Required
S	Therapeutic Interchange/Substitution
D	Drug Use Evaluation
S	Script Clarification
OS	Pharmacy is out of stock
U	Prescriber Authorization

S really does carry two meanings. Canvas maps it to both Therapeutic Interchange/Substitution and Script Clarification, so the two are indistinguishable from type_code alone.

The sub_type_code attribute further qualifies the request. It is nullable and currently supports:

Code	Description
A	Confirm Prescriber State License

Attributes #