I am experiencing the same issue, although I am on a slightly different medication (Sintrom). I was also wondering whether it had something to do with increased activity levels. Although I am not fully back to work 2 months after my PE, I am doing a lot more than before (I had my first light workouts, I work 2-3 hours a day when I feel good enough, I take some walks). The people at the thrombosis center told me it's not a matter of increased activity though... They only told me that in the first months/year of treatment is common to have these "rollercoasters".

Did you change the way you eat or the time of your meals?

No i haven't changed my meals. I read everywhere that activity level affects INR but my doctors say the same thing. I'm taking a medium range flight tomorrow and I need my INR to get back to being therapeutic.

An increase in activity does lower my INR. And when I eat fewer calories, my INR is higher so it's not always what you eat. For some people it really is true that for the first few months of being on it, it can be very up and down. My INR was low for the first 5 months I was on it; some people need a higher dose to really maintain a therapeutic INR.

I think true warfarin resistance is usually evident early on when your first start taking it.

i've been therapeutic up until about 5 weeks ago and thats about when i started working so much.

bsmith, I also had my first flight last week when my INR was not in range. Ask your doctor if it's still safe for you to fly, perhaps he could propose a heparin shot just to be sure that you're going to be fine.

they said it's still safe but to move around every hour or so. none of my doctors, PCP, Rhemy, or Hemo recommended heparin but then again i didn't ask

I went through the same thing where my doc would up my dosage and my INR stayed the same or it went up like a point and then come back down. My first year on warfarin was really a roller coaster ride. I really don't think you have a resistance. I think that you're young and healthy and it's likely your body needs a higher dosage to get in range and stay there. But most docs don't want to make big dosage changes in response to a low INR because it can really overshoot your range then, and then you're on a see saw, up and down, up and down. So it's a long tedious process of dialing into the right dosage for your body.

How long is your flight?

2 hours to minnesota and then 4 to california...they just said walk around and do leg exercises

Drink a lot of water too. I do think you should be ok as well particularly if you get up and walk around, do leg stretches, ankle circles and foot pumping ( like pressing up and down on a gas peddle). But if you're super concerned, call your hema or PCP and ask for lovenox and see what they say.

i'd rather avoid needles haha. i also take plaquenil which i guess is for my lupus but it also helps prevent the proteins in my blood from binding so that's kind of my back up

I think your approach is sensible. I do. And I do think if you truly felt you were at risk, you'd suffer the needles, so that's good too.

I completely think that changing your activity level could affect your INR. The theory I've heard is that your blood moves more and make more trips through the liver as a result. Since the liver cleans out things like medicine from the blood, more trips through the liver would result in the warfarin getting cleaned out of your system faster. So, an increase would be necessary.

Also, I know with me, my diet does change when I'm working. If things are kind of high stress and I'm really busy, I eat a lot less and I have fewer meals and more snacks that I just grab along the way. 60 hours a week sounds pretty busy, so it is possible that your calorie intake has changed a little without you even realizing it.

Either way, if you take precautions on the flight, you ought to be fine. You're educated and aware of clots--and you're taking precautions--which (by itself) will help make you safer than most everyone else on the plane.

My INR did some wacky things in the early days, too. Went from 1.3 the date of discharge to 4.8 four days later at my check. Reduced the dose. Went up to 4.9. Reduced the dose. Went down to 4.6. Reduced the dose. Was 4.7. Then they halved the dose and tried going up at it instead of down. That worked until I went back to work. Less fluid intake, fewer calories, more physical activity....my INR went down to 1.7 and they had to increase it again. So lots of things affect the INR, especially in the early going when your diet and exercise levels change from stay-at-home to back-to-work.

Well, I've had the opposite problem of having my INR too high after 4 years of stability. I can't pinpoint anything that's different but it's been crazy with my levels going up and dropping my dosage of warfarin. I don't want to scare you, but I had another clotting episode in January while we were waiting for my level come up.(after I had been off warfarin for a procedure). My doctor should have had me on lovenox until my levels were therapeutic. Now it's too high. I'm having surgery on 8/7, so I wonder what will be going on when I get back on my warfarin and I will be on lovenox until my level is therapeutic for 1 week. I hate those shots!