Metformin IV contast

  1. What is the current practice and/or recommendations for IV contrast and metformin? I believe my teacher was teaching old information and I'm trying to clarify. I don't really know, but maybe what is done in practice is not necessarily what is recommended?
    •  
  2. 13 Comments

  3. by   JustKeepSmiling
    Metformin is a nephrotoxic drug and so is IV contrast, both even to a healthy kidney. If metformin is not held before & after IV contrast it can cause AKI, or worse in a patient who already has renal insufficiency or dialysis.

    Emergent situations aside, it is typically held 48 hours before and after contrast.

    Blood sugar in between can be controlled with insulin. Kidney injury, not so easy to fix...
  4. by   truckinusa
    Quote from JustKeepSmiling
    Metformin is a nephrotoxic drug and so is IV contrast, both even to a healthy kidney. If metformin is not held before & after IV contrast it can cause AKI, or worse in a patient who already has renal insufficiency or dialysis.

    Emergent situations aside, it is typically held 48 hours before and after contrast.

    Blood sugar in between can be controlled with insulin. Kidney injury, not so easy to fix...
    I have read that in my book too, but the American College of Radiology states(I'm assuming they are an authority?):

    In patients with normal renal function and no known comorbidities, there is no need to
    discontinue metformin prior to intravenously administering iodinated contrast media, nor is there a need to
    check creatinine following the test or procedure.
  5. by   nycsurg
    You can discontinue metformin after the CT scan.

    Also the chance of lactic acidosis is very small to begin with.
  6. by   dianah
    Our practice is to instruct pts to hold Metformin day of procedure and for 48hr after, monitoring urine output (thought is to withhold it AFTER the contrast, and hydrate well pre and post contrast).
    If they "pee less than a Styrofoam cup" in the 48 hr post procedure, do not resume Metformin and call PMD immediately.

    Check ACR (American College of Radiology) recommendations for best practice, contained in their publication Manual On Contrast Media (available for viewing online).
    Manual on Contrast Media v9 - American College of Radiology
  7. by   michlynn
    We hold Metformin for all of our cardiac cath patients regardless of age/health from the day of admission and resume it 3 days later. We'll stick the patient on a low dose sliding scale insulin during their stay.
  8. by   amychisom
    Our practice holds the Metformin for all cath patients too regardless of heath/age day of procedure and resumes it 3 days later. Will also place on low does of sliding scale. We had reviewed the ACR guidelines and this was what our docs chose to do, but each practice varies on their own procedures.
  9. by   JustKeepSmiling
    I have encountered patients with severe renal impairment after a cath where contrast was given and metformin on board. (I.E. STEMI pt who took metformin that morning)

    As healthcare professionals we have to do what is best for the patient.

    Would you rather risk your patient getting renal impairment, perhaps dialysis, or cover them with insulin while metformin held?
  10. by   dianah
    Many factors contribute to risk of renal impairment post-contrast administration:
    Age
    Diabetes (and how well-controlled it is)
    Hydration status
    Renal function pre-contrast administration
    Exposure to nephrotoxic drugs
    Amount of contrast used (if PCI done as well as diagnostic cath (likely for STEMI pt), more contrast will likely be used = greater risk for renal injury)


    Interesting and applicable article here: Medscape: Medscape Access

    Per the article, pre-existing renal impairment is most important to be aware of and one of the most important predictors of possible CIN, contrast-induced nephropathy.

    It behooves all of us to be aware of the risks and mitigate when and where we can.
  11. by   MOSTLYHAPPYRN
    At both hospitals where I have worked as an RN, the MD usually will hold metformin upon arrival and start pt on a sliding scale for insulin coverage. Then if pt has to get a CT with contrast, we continue to hold it for at least 3 days-and usually until pt is discharged. There are a lot of measures in place so that pharmacy as well as each person looking at pts chart is aware that pt received contrast and metformin is being withheld.

    What did your teacher say?
  12. by   truckinusa
    The teacher was going with the textbook which said to withold 48 hours prior to a CT scan.
  13. by   dianah
    I wonder how recent was the edition of the textbook?
    Some years ago (over 10yr) that was the policy, to withhold it 48hr pre.
    The most recent recommendations are posted in links earlier in this thread.
  14. by   canned_bread
    We advise patients to cease metformin 48 hours prior to the scheduled contrast injection. This is because we have seen (and also done our own studies) of higher creat if we didn't, indicating kidney damage. Some kidney damage is temporary, some is not. Diabetics often have compromised kidneys to begin with!
    I do not know if it is dose dependent. Some of these cases we used a lot of contrast (100+mls of 320 omnipaque etc), and some was a small amount of diluted contrast (say 50/50 300 omnipaque just 20mls in total).
    We also pre-hydrate with normal saline in patients with a high risk of kidney injury, regardless of metformin usage or not. We post-hydrate with at least 500mls of normal saline for everyone.

close