Coumadin/Warfarin allergy testing?

[Odie]

I'm a 50 year old BAV having AVR in 3 weeks. I'm going with a mechanical valve. To date, no one has suggested testing for allergies to anti-coagulation drugs. I understand that allergic reactions are not common but seems like a pretty big "oops" moment to find out after AVR that one couldn't tolerate Coumadin.

My questions are:

1. Is testing available?

2. Was anyone tested before selecting a valve type?

3. What options exist for someone who develops an allergy?

 

[Bina]

This is a good question, and fortunately reactions or sensitivities are very rare with Warfarin. Some people may react to the filler or colourants in their particular brand or dosage, but my doctor
prescribed the name brand Coumadin and it has worked well for me. There are a couple of generic brands with a large range of dosages that can be an option if needed.
Also, a few members here have tried taking a non-warfarin based anti-coagulant which seems to be more popular in Europe.
It's not something that I was concerned about pre-surgery even though I am sensitive to many meds.

 

[cldlhd]

It makes sense to me . Considering what would happen if you find our after even if its rare why not check. Its on my list of questions I have for my surgeons meeting on May 20th.

I'm a 50 year old BAV having AVR in 3 weeks. I'm going with a mechanical valve. To date, no one has suggested testing for allergies to anti-coagulation drugs. I understand that allergic reactions are not common but seems like a pretty big "oops" moment to find out after AVR that one couldn't tolerate Coumadin.

My questions are:

1. Is testing available?

2. Was anyone tested before selecting a valve type?

3. What options exist for someone who develops an allergy?

 

[pellicle]

Hi

I'm a 50 year old BAV having AVR in 3 weeks. I'm going with a mechanical valve. To date, no one has suggested testing for allergies to anti-coagulation drugs. I understand that allergic reactions are not common but seems like a pretty big "oops" moment to find out after AVR that one couldn't tolerate Coumadin.

I have posted here on exactly that point (in responce to one who seemed to be having difficulty with warfarin) but it seems that totally noone does this.

Seems QED to me (to do such) but just isn't done.

I can only conjecture that its not done because:
1) it takes some months to stabilise on warfarin and requires that the person and the clinic are interested: this is expensive and perhaps most people aren't interested

2) there is a small risk associated with starting warfarin therapy, so if you aren't going to be taking it, why take the risk?

3) I have only ever found (in my looking) one case of warfarin 'allergy' and it was found to be to the dye in the pill not to warfarin. (url)

As a general related discussion I wonder how much "problems" with warfarin are related to management and management of expectation. For example people here report their INR has not stabilised, yet few actually say what their INR is and what the variance is.

From what I've read "adverse reactions" (as differentiated from allergic reactions) are in the main related to comorbidities like, renal deficiencies, liver disfunctions, diabetes, circulatory problems and gastric problems. If you don't have any of those things you should be fine.

People (me included) get anxious (I got anxious) in the first 6 months or year .. but then it transits to "meh, no problem"

 

[mbeard]

I hope some more people respond to this thread. Interesting question.

 

[pellicle]

oddness occured I've edited this as blank

 

[pellicle]

very weird ... I wonder what happended to cause a duplicate post by editing?

Ok, well since this post is here I'll make use of it by posting my INR history for 2013

you will see much variation in there, but if you look at where the highs and lows are you'll see that its within (quite) acceptable limits.

My point is this: some people would cover their mouth and point saying "oh gosh, look at how unstable that is" ... I will say that its a living system, its never going to be static and the goal is to be within acceptable limits over the majority of time. Even a bulls-eye is bigger than the size of the bullet.

 

[T in YVR]

I posed this question to the doctors, surgeon, etc that I saw before my surgery. I shared your concern and was doing my due diligence on everything I could think of before surgery.

Essentially I was told that: (a) no they do not have allergy testing for warfarin/coumadin and (b) if this was a big concern and you had lots of time before your surgery (i.e. you would not do this if the date was nearing!!), you can get a 1-time small prescription and go on warfarin for a 3-4 week period and see how your body reacts (might be able to determine if there was an allergic reaction in less time than this - not sure). There is no big risk or life threatening type of adverse reaction/allergic response from what I was told (skin irritations?). And if all goes well, you just have a raised INR for a short period of time. Not sure what dosage of warfarin you would take under a test scenario, but I think it certainly would be on the low side. I was too close to my op date when I got some of these answers, so I went into the surgery like most of us - not knowing if you are one of the very few people that has an allergic reaction. I think the risk is pretty low.

T

 

[tom in MO]

Alergic reactions to warfarin are rare. There is no need to "try it out."

As to "developing an allergic reaction" it's not part of the official warning AFAIK and it's never been reported here.

Putting allergic reactions aside, there are a very small minority of people who have trouble with getting a stable INR with warfarin therapy, but that takes weeks to find out.

 

[Odie]

Thanks to everyone for the insightful replies!

 

[Jkm7]

I did not have an allergic reaction to warfarin, per se, however, I discovered I require huge doses to reach range of 2.5 - 3.5. I am very grateful I chose a tissue valve, as post surgery when my surgeon required I have a 3 month course of warfarin while my own tissue grew over my new valve seating, despite my going to a highly competent, reasonable coumadin management lab and my being extremely compliant, I never reached my range. My coumadin management was handled meticulously with small incremental increases in dose, reasonable length of time between testing and I never once was 2.0 despite taking 100mg warfarin and headed to even higher dose when my surgeon said to stop. He did not like my taking such a huge dose and at 2 1/2 months he stopped it.

I could not have known this in advance of beginning ACT and if I had gotten a mechanical valve, this could have been problematic for other medical or dental procedures which could cause bleeding. It could have been a real problem if I was taking that huge dose for a great many years.

Yes, I know the proper dose is that which keeps each of us in our prescribed range and that is different for all of us but few of us would be comfortable or particularly happy taking well over 100mg warfarin week after week, year ater year.