---
title: CancelRx and CancelRx Response
slug: eprescribing/guide/cancelrx-and-cancelrx-response
docTags: 
createdAt: 2026-06-22T21:09:17.013Z
---

# CancelRx and CancelRx Response Overview

The CancelRx is sent by the prescriber to notify the pharmacy that a previously prescribed prescription should be inactivated, and no additional product should be dispensed.

The CancelRxResponse is sent from the pharmacy to the prescribing system in response to a CancelRx.

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**Reference: **Specific formatting exists for CancelRxResponses, for more information see the NCPDP SCRIPT Implementation Recommendations, V1.69 (or latest version) Section 12.1.
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## CancelRx and CancelRxResponse Requirements

**R.314:** Receiving systems shall not automatically deny a CancelRx message due to the absence of either the PrescriberOrderNumber or the RelatesToMessageID.

## CancelRx and CancelRxResponse Provider Best Practices

- When a CancelRx message is sent, a ReasonForCancellation should be sent to provide context for why the prescription is being cancelled.
- If the ReasonForCancellation is an allergic reaction, then the patient's allergies should be included.

## Prescribing System-Initiated Change Process for LTPAC - Requirements/Best Practices

- **R.312:** In LTPAC prescribing systems, when making a prescription change using a CancelRx followed by a NewRx, a MessageRequestCode shall be used to identify the type/severity of change made. This field shall be sent in both the CancelRx and the subsequent NewRx.
- The ChangeOfPrescriptionStatusFlag should contain the appropriate code for canceling a medication that has not been dispensed or discontinuing an active order.

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**Values**:
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C = Use for canceling a prescription prior to a dispensing (administration)
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D = Used for canceling a prescription that has been dispensed (administered)
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- Some scenarios for Prescriber-Initiated Changes include:
  - A data entry error is corrected by a prescriber or an agent of a prescriber and a CancelRx is sent with a subsequent NewRx.
  - A prescriber alters a course of therapy after making a clinical decision regarding a medication and sends the pharmacy a CancelRx followed by a subsequent NewRx.
- CancelRx should contain a CodeListQualifier value of "QS" (Quantity sufficient as determined by the dispensing pharmacy) or "CF" (Compound Final Quantity) and Quantity of "0" when discontinuing an open order.