Thanks to Ashley Stein-Merlob for presenting a case of a woman on warfarin with some very wild labs and a supra therapeutic INR. Let’s get bread and butter for a moment and talk about ddx/management of a supra therapeutic INR
Divided into things that affect intake, absorption, or metabolism
- taking too much or too little warfarin
- changes in dietary intake of vitamin k (you could also see this as metabolism but that’s splitting hairs =)
- meds that prolong or speed up metabolism
- illnesses that affect hepatic perfusion (sepsis, decompensated heart failure)
- new liver dysfunction/failure
- In the real world, the most common cases are
- dietary/adherence related
- heart failure
- If bleeding, reverse! Use IV vitamin K, which reverses faster, and FFP vs PCC depending on the tempo, severity and location of the bleeding. Details of this another time.
- Check out this fancy table from the American College of Chest physicians about managing INR in every imaginable circumstance.
A brief digression
This patient’s INR went from 6->1.7 12 hours after receiving oral vitamin K. Is that… wild? Unheard of? Normal?
Turns out the answer is uncommon, but not unheard of. Below is a table from a paper comparing the time to INR reversal for IV and PO vitamin K.
My big takeaways are
- IV vitamin K works faster and should be used in patients who are bleeding
- you may have learned in med school that IV vitamin K is associated with a higher rate of anaphylaxis. Larger studies have debunked this myth, so don’t be afraid!
- 14% of patients have their INR completely reversed within 12 hours with 1 PO dose of vitamin k
Have a fabulous weekend!
Meehan R1, Tavares M, Sweeney J. Clinical experience with oral versus intravenous vitamin K for warfarin reversal.Transfusion. 2013 Mar;53(3):491-8
Ansell J1, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G; American College of Chest Physicians.Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008 Jun;133(6 Suppl):160S-198S.
Mike Hurley, this bonus paper is for you (I’ll write pearls about this sometime soon):
Mehanna HM, Moledina J, Travis J. Refeeding syndrome: what it is, and how to prevent and treat it. BMJ 2008 vol 336 June. p1495-1498
Filed under: Morning Report