Hey #MedTwitter ready for another mystery?
Patient presents with angina and is found to have 3 vessel disease for which he undergoes CABG.
Pre-op INR 1.6
Post-op INR >13.6
What did we give him to trigger this? (Hint: it’s not warfarin)
Patient presents with angina and is found to have 3 vessel disease for which he undergoes CABG.
Pre-op INR 1.6
Post-op INR >13.6
What did we give him to trigger this? (Hint: it’s not warfarin)
It was actually cefazolin!
There’s a side chain inhibits vitamin K epoxide reductase and/or gamma-gutamyl-carboxylase altering synthesis of vitamin K dependent clotting factors and thus has a warfarin like effect in some patients.
There’s a side chain inhibits vitamin K epoxide reductase and/or gamma-gutamyl-carboxylase altering synthesis of vitamin K dependent clotting factors and thus has a warfarin like effect in some patients.
Obviously this doesn’t happen every time we give cefazolin - it seems to be more likely in patients with recent surgery, renal failure, cancer, ileus, and poor nutritional status at baseline.
We reversed this patient with 10 mg of IV vitamin K and two units of FFP to an INR of 1.2
Here’s another case that was published where cefazolin increased a patient’s INR
pubmed.ncbi.nlm.nih.gov/18436729/
pubmed.ncbi.nlm.nih.gov/18436729/
I thought this case was really fascinating because not only was this a side effect I had never heard of with cefazolin before, but it’s also a perfect example that antibiotics are not always a benign intervention.
Another case for #stewardship
Another case for #stewardship
Side note: do not endorse Moira Rose’s understanding of antimicrobials
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