Home Forums INR Home Monitoring

I have a number of patients who live 40=50 miles away with whom I would like to try INR home monitoring. Wondering if anyone has experience with this. I just downloaded a form from Phillips. Will be looking at Roche as well. In my area, none of the retail pharmacies are carrying them yet.

Hi Vicki,

Sorry I missed this when you posted it. Our family has just had two graduations, and yesterday our oldest left for Peru for a two year stint in the Peace Corps. So my life has been a bit hectic!

I have several patients using home INR. From my point of view, there is really no extra work and no extra effort. Several of the local oxygen suppliers are handling these. They train the patient, set things up in their home, and so forth. The patient does a finger stick at least once a week, they use a telephone line to transmit this to Phillips, and Phillips will fax the result through to our office that afternoon.

The local companies, at least for Medicare, require that the patient has been on Coumadin at least three months before they will supply a home unit.

Hope this helps!

Gene

On this subject, I am quite new with interpreting INRs. I have a patient who has/had a DVT in the left cephalic vein. This was diagnosed in early May. His INR seems to fluctuate between 1.4 and 3.5. I follow the guidelines in the latest Harriett-Lane.

My main question is how long should I waiting between obtaining INRs. His visiting nurses will go out any day I ask. He is only on it for three months, so one month has gone by. I have read different things. I don't know if it depends on how stable someone's INR is.

Hi Bert,

I'm not sure if there's any area that is more a matter of judgment, experience, and art than this. My general approach:

At the time of starting warfarin, I will check Protime/INR twice weekly, until we obtain about three values which are relatively consistent and within range. I will then check weekly, after two or three are consistent and in range, next one will be two weeks, next one will be three weeks, then monthly afterward.

Some people follow this schedule and are absolutely consistent on the same dose of warfarin. Others are always up and down. There are some people who will require weekly testing for the duration. Others will be stable for a while, they can space out to monthly, but then values will change and they'll be back to weekly for a while.

In terms of changing dosages, I try not to go too far overboard with making changes. Patients accidentally missing a dose, or taking a second dose, will alter the results, but obviously don't require a change in therapy. Sometimes I think that abnormal results are as likely lab variation, as a true change in patient status. Example: An older person who is been stable on a given dosage for years, all of a sudden goes high or low, we call them and they say they have not missed doses, changed their diets, or so forth. Often I will not change anything, and just have them get another INR in a week, more often than not that one is normal.

I try to have everyone get a prescription for warfarin 5 mg. Typically I will have them work with whole and half tablet, for example take a whole tablet five days a week, and a half tablet on Monday and Thursday. Older patients seem to do very well with this approach. To have someone take 3 mg daily, and then switch to 4 mg daily, will require a new prescription, additional cost, and great potential for confusion.

After all this rambling: when stable, monthly protime/INR is sufficient. For your patient, weekly protime/INR might be best.

Hope this helps!

Gene

Helps a lot. Big question, well for me, lol. Is it worse to be low and risk clots or high and risk bleeds. And, when they come back 4 or 5, should I warn him about playing rugby?

Damn, just when I set this up to show up in MRP, I have to come on and show how stupid I am.

Hi Bert,

I believe I have shown my stupidity regarding computer-related things on numerous occasions over the last few years.....

Seriously, stupidity has nothing to do with it. This is one of those areas where experience is key.

Personally, I tend to keep people on the low side, rather than the high side. To my knowledge, the actual literature regarding optimal INR is pretty sparse. The one study I'm familiar with, involving atrial fibrillation, showed that INR 1.7 did not work, I think the next data point was about 2.3, which did work. But I have been unable to find any information as to whether 1.8 is as good as 2.1, etc.

I would probably tend to limit contact sports when INR is above about 3.5. This is a totally arbitrary number.

Have you considered use of Xarelto? I don't have time to check the package insert now, but this is approved for DVT, both prophylaxis and treatment. The advantage to this is that it does not require dosage titration, checking INRs, and there are no dietary restrictions.

Gene

As usual, thanks Gene.

Hi Gene,
Thanks for your reflection on the home inr monitoring. Looking forward to trying it out.