Document Title: Clinical Guideline Template

Number: / ????-???-??? / Version: / 0.0 / Status: / Draft / Dated: / Dd/mm/yyyy

Clinical guideline for the use of iodinated contrast media for patients taking Metformin

Document Number:

Sponsor:Radiology

Date Created:December 2011

Version:1.0

Status:Issued

Date Approved:14.12.2011

Next Review Date:14.12.2012

Approved By:Radiology Clinical Governance Steering Group

Note: This document is electronically controlled. The master copy of the latest approved version is maintained by the owner department. If this document is downloaded from a website or printed, it becomes uncontrolled.

Printed on 23/10/18 at 14:30Page 1 of 5

Document Title: Clinical Guideline Template

Number: / ????-???-??? / Version: / 1.0 / Status: / Issued / Dated: / 14.12.2011

Table of Contents

1.Document Definition

1.1Revision History

1.2Review and Approval History

1.3References & Further Reading

1.4Glossary/Definitions

1.5Purpose

1.6Scope

1.7Regulatory Position

1.8Special Cases

1.9Equality Impact Statement

1.10Comments

2.Clinical Guideline

1.Document Definition

1.1Revision History

Version / Status / CR No. or Reason For Change / Date / Author
0.0 / Draft / New document / dd/mm/yyyy / Job Title
0.1 / Draft / Incorporated Initial review comments
1.0 / Issued / After Final Review

1.2Review and Approval History

For the avoidance of doubt, the latest approved version of a document remains valid until it is superseded or withdrawn, regardless of whether the date for the next review has passed.

Version / Reviewer/Approver / R/A / Scope / Date
0.0 / New Document / dd/mm/yyyy
0.1 / R / Context, completeness and accuracy
1.0 / A / Current and compliant

1.3References & Further Reading

Ref. No. / Document Title / Document Location
1 / Standards for intravascular contrast agent administration to adult patients (Second Edition) 2009 /

1.4Glossary/Definitions

The following acronyms are used within the document …

CT – Computed Tomography

IVU – Intravenous Urogram

RCR - The Royal College of Radiologists

1.5Purpose

The purpose of this guideline is to clarify when patients are to be instructed to suspend their Metformin medication following contrast media injections. The current procedure is that all Metformin patients are told to stop taking their medication for 48 hours after contrast injection, and to maintain good hydration. However in the light of new RCR guidelines this is not always applicable1.

1.6Scope

1.7Regulatory Position

1.8Special Cases

1.9Equality Impact Statement

Great Western Hospitals NHS Foundation Trust aims to design and implement services, policies and measures that meet the diverse needs of its service, population and workforce, ensuring that none are placed at a disadvantage over others.

This document has been assessed against the Trust’s Equality Impact Assessment Tool.This document has been assessed as relevant/not relevant to the duty.

(*delete either ‘relevant’ or ‘not relevant’, as appropriate, then remove this line).

1.10Comments

Any comments on this document should, in the first instance, be addressed to the author.

2.Clinical Guideline

Current advice1 from the RCR on the uses of iodinated contrast agents in patients taking Metformin is based on guidance from the European Society of Urogenital Radiology and set out in the RCR publication, BFCR905)7 Standards For Iodinated Intravascular Contrast Agent Administration To Adult Patients which states:

Metformin is not recommended for use in diabetics with renal impairment, because it is exclusively excreted via the kidneys. Accumulation of Metformin may result in the development of serious complication lactic acidosis. Although the incidence of lactic acidosis following contrast administration in diabetic patients receiving Metformin appears to be extremely low, extra care should be exercised in these patients.

Advice:

  • If the serum creatinine is normal, and a low volume of contrast agent (up to 100ml) is to be administered intravenously, no special precaution is required.
  • If the serum creatinine is normal, but more than 100ml of contrast agent or the intrarterial route is to be used, Metformin should be withheld for 48 hours after the procedure.
  • If the serum creatinine is raised, the need for the contrast agent should be re-assessed. If contrast injection is deemed necessary, Metformin should be withheld for 48 hours before and 48 hours after the contrast is given and the renal function re-assessed before restarting the Metformin treatment.

The guideline from the RCR now reads:

There is no need to stop Metformin after contrast in patients with serum creatinine within the normal reference range and/or eGFR >60ml/min. If serum creatinine is above the normal reference range of eGFR is below 60, any decision to stop it for 48 hours should be made in consultation with the referring clinician.

This reflects the lack of any valid evidence that lactic acidosis is really and issue after iodinated contrast in patients taking Metformin, the problems caused to patients and clinicians by stopping the drug and its increasing use in poorly controlled diabetic patients regardless of renal function. It does, however, remain the case that renal function should be known in patients taking Metformin who require intravenous or intra-arterial contrast agents.

Therefore, for both CT and IVU contrast injections, the renal function must be checked, especially for patients taking Metformin and follow the above RCR advice when making decision about contrast administration to these patients.

Note: This document is electronically controlled. The master copy of the latest approved version is maintained by the owner department. If this document is downloaded from a website or printed, it becomes uncontrolled.

Printed on 23/10/18 at 14:30Page 1 of 5