Metformin and IV contrast

I think that we hold the Metformin as soon as we know they are scheduled for any radiology procedure that requires iodinated contrast and then we keep holding it for 48 hours after the procedure. I guess I don't know too many brittle diabetics that take Metformin because I see it used mostly for Type II diabetics. I would think one would monitor glucose levels closely and if the pt is running high, maybe they would temporarily need sliding scale insulin.

Well I guess I am not of much help to you. I do know that we hold the Metformin for 48 hours after the procedure and a renal panel is done before and after. Most of the people I deal with are inpatient.

I am glad to be of help. I do know that we have a written policy on Metformin in relation to iodinated contrast studies. I have done teaching with pts on early s/s of lactic acidosis. It sounds like your pts could also potentially have problems with renal insufficiency? I would rather be cautious than not.

The recommendation of the American College of Radiology (ACR) is to withold the Metformin the day the contrast is administered and for 48 hours post administration, re-starting the dose only after renal function has been evaluated and found baseline (pre-administration levels).

See if you can either get a copy of the ACR's Contrast Administration guidelines (perhaps your Radiologists have a copy of may obtain one for you) or contact your diabetes teaching RN, NP or the endocrinologist who serves your facility.

Debbie,

It is standard protocol to hold any medication containing Metformin for 24 hours prior to a procedure requiring IV or IT iodine contrast media. The medication should be held also the day of the procedure and for an additional 48 hours post procedure. These patients should be given an order for a bun/creatinine lab to be drawn 48 hours post exam. In some facilities, the lab work is reviewed prior to the patient restarting their medication. There are a total of 19 medications containing metformin which I have listed for your reference. Any of these medications can cause a drug-drug interaction with the contrast media.
Glucophage, Metformin, Glucophage XR, Avandamet, Glucovance, Actoplus Met, Glumetza, Riomet, Metaglip, Fortamet, Glucovan, Alti-Metformin, Apo-Metformin,Glycon, Novo-Metformin, Nu-Metformin, PMS-Metformin, Rhoxalmetformin FC, and Rho-Metformin
Good Luck,
Vanita DeBar

Metformin does not lower blood glucose only makes the pancreas more efficient. When a patients blood glucose is low i.e. 70, the metformin is not held.

Metformin taken with contrast can lead to acute alteration of renal function and has been associated with lactic acidosis. That's why BUN/Creatine are done prior to CT and why metformin is held the day of the procedure and for 48 hours after procedure.

ACR Manual on Contrast Media

Metformin Therapy and the Risk of Lactic Acidosis