vitamin K-induced warfarin resistence

[Hamhock]

Anyone ever heard of this?

I was about to give a bunch of oral vitamin K to an EtOHer with minimally functional liver the other day when an attending brought up a new reason to be cautious with vitamin K.

The attending stated that up to 10% of patients treated with oral vitamin K for warfarin-induced coagulopathy will subsequently become warfarin resistant.

Obviously this has nothing to do with the EtOHer's coagulopathy, but the attending was trying to get me to think about my use of oral vitamin K more. He said the risk-benefit analysis of this iatrogenic resistence must be especially considered in patients with metallic valves who are not actively bleeding but have an INR > 10.

I tried searching PubMed, but came up with very little...a line here and there, but not as much as I would expect for a potential complication affecting up to 10% of patients on coumadin.

Anyone ever heard of this?

HH

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[BADMD]

The attending stated that up to 10% of patients treated with oral vitamin K for warfarin-induced coagulopathy will subsequently become warfarin resistant.

Obviously this has nothing to do with the EtOHer's coagulopathy, but the attending was trying to get me to think about my use of oral vitamin K more. He said the risk-benefit analysis of this iatrogenic resistence must be especially considered in patients with metallic valves who are not actively bleeding but have an INR > 10.

I don't believe this is a permanent thing. But as they are now very vitamin K replete, they may resist their previous dose of warfarin until those store are used up. Do I have some great evidence for you? No. Have I heard of it? Yes.

I was about to give a bunch of oral vitamin K to an EtOHer with minimally functional liver the other day when an attending brought up a new reason to be cautious with vitamin K.

Keep in mind that someone with a minimal/non functioning liver, Vit K probably won't do a whole lot. These individuals have a synthetic function problem and not a Vitamin K problem.

 

[southerndoc]

I was taught no vitamin K unless they're actively bleeding. If they're on warfarin for a-fib or DVT/PE, then vitamin K can be used if actively bleeding or INR >10. If they have mechanical valves, then one should avoid vitamin K unless the person is exsanguinating, and even then it will take a while to work.

The problem is that when you give a person vitamin K, when their INR returns to normal, they have to up their dose of warfarin to get therapeutic again. Sometimes it'll take 5 times the normal dose they were on. Then when the vitamin K starts to wear out, suddenly they're coagulopathic again and thus you begin a new cycle.

 

[gramcracker]

Agree with southerndoc. I've heard complaints from the inpatient service that we gave Vitamin K and "now it's hard to get them therapeutic again" (they seem to forget that we gave them vitamin K because they were supertherapeutic *and* bleeding).

Also, perhaps this was more a general idea than specific to the patient in front of you, but active heavy alcohol consumption is an absolute contraindication to warfarin usage, and falls and uncomplicated liver disease are both relative complications as well.

Keep in mind that someone with a minimal/non functioning liver, Vit K probably won't do a whole lot. These individuals have a synthetic function problem and not a Vitamin K problem.

Depends on the cause of their coagulopathy: sure, the cirrhotic alcoholic will have synthetic function problems, but the "simple" nutritionally-deficient alcoholic may just lack Vitamin K itself.

 

[BADMD]

Depends on the cause of their coagulopathy: sure, the cirrhotic alcoholic will have synthetic function problems, but the "simple" nutritionally-deficient alcoholic may just lack Vitamin K itself.

Hence the "mininal/non functioning" part. A nutritionally deficient alcoholic has a functional liver.