After 14 months I missed a dose of warfarin…

[GreenGiant91]

So I have alerts on my phone to take my warfarin every night at 6pm and I’ve not missed a single one…. Until yesterday. Only noticed I missed it this morning when I seen the tablet sitting in my tablet tray marked Wednesday PM. Feel like an idiot for missing it, I tested myself yesterday morning which was at 2.6 and this morning it’s dropped to 2.2. Hoping it will stay in range okay but it’s a lesson to make sure to take the tablet as soon as the alert goes off on my phone and a reason to have a tablet tray so you can spot when you’ve missed your dose.


D’OH!!

 

[Chuck C]

Thanks for sharing your experience GreenGiant.

You should be just fine.

1) 2.2 is still is the INR safe zone
2) You discovered the mistake by the morning, so you should have only had about a 12 hour delay in your dosage
3) warfarin has a long half-life, which reduces the risk in such an event, although obviously, we still want to take mitigating steps to avoid its occurance.

I've been on warfarin for almost 4 years and did miss one dose in that time. My outcome was similar to yours, seeing a drop in my INR, but still in the safe range.

For a very rough analagy, missing a dose is a bit like playing Russian Roulette. Assuming one is in range at baseline, it is sort of like the gun has a 500 round chamber and one round is placed in it, for missing just one dose. Very low risk that this will lead to an event. On the other hand, if missing dosage becomes a regular occurance, perhaps even multiple times per week, it becomes more like a 6 round revolver or 12 round revolver that we are playing with. Do it enough times and regularly, and it will likely lead to a bad outcome eventually.

And to be clear, I'm not suggesting the odds for the above analogy are accurate, just generally that missing one dose increases our risk, but very minimally. Missing doses often, much more risky.

 

[Superman]

It’s why I take it in the morning. Too much stuff going on in the evening increases the likelihood of a missed dose for me. But I always have my morning OJ and take my pills with it.

Not that I’ve never missed in 34 years. I’m sure I have.

 

[pellicle]

Only noticed I missed it this morning when I seen the tablet sitting in my tablet tray marked

So, the systems of redundant checking work and you found it. Just take it as soon as you notice it.

Easy

 

[pellicle]

Compared to Superman we're beginners ...

I've been on warfarin for almost 4 years and did miss one dose in that time

I think that's about my average too ... perhaps its one every two years, but I'm not concerned with that. I'm more interested in being in range most of the time. This is one of the core strengths of warfarin: half life.

A single dose of warfarin will remain in ones system for something like this time:

so because we then load up every day with more we get something like this sort of accumulation

(modelled on a 10mg dose and a 48 hour half life, which is about median)

Because of the accumulation in our bodies of the stuff being 12 hours or so out (or even missing a dose entirely) won't drop much and equally won't take long to return from what is a trivial deviation.

So lets model this ...

Initially we see that accumulation of warfarin in our systems, then lets look at the results from three strategies

• Do nothing: I miss a dose and we can see that accumulation falls, then returns in a few days
• Take next day ...
• Split the remainder across the following days ...

each of these takes the same amount of time to wash out. Note I didn't bother with the "take it as soon as you see it" because that's typically going to be less than 24 hours and is harder to model and will have even less effect.

Note this is the simple theoretical model of accumulation (one compartment model) and may or may not reflect the INR outcome. Remember that INR is not directly acted on by warfarin, (not least) because warfarin act only on your Vitamin K recycling, its an indirect drug. INR is also influenced by what else goes in our mouth (alcohol, Vitamin K ...) so my view is don't overly fret it.

This is also a good time to remind people why you don't sit on the bottom of your range, and that you should aim for the target (not the lower limit)

(NB the above is said for @GreenGiant91 and general reading, not for you cos I know your well across this)

 

[GreenGiant91]

Thanks all the for comments.

I have my meds on my iPhone health app and it sends me a notification to take it and will stay on my home screen until I either clear it or mark it was taken. I’ve set up a further alert to trigger 30 mins later if I haven’t marked it as taken. Not sure what happened, I remember getting the notification but then just completely blanked and went about my evening.

Rang my doctor who advised me to take a slightly higher dose today (4mg instead of the normally 3mg). I’ll test again in a few days and hopefully still in range. I’ve always been very good at taking it when I’m busy but some reason it just went completely out of my head last night.

I actually done my weekly test yesterday morning which is how I know I was on 2.6 yesterday. I’m happy I wasn’t sitting at 2.0 before forgetting it.

 

[pellicle]

I actually done my weekly test yesterday morning which is how I know I was on 2.6 yesterday. I’m happy I wasn’t sitting at 2.0 before forgetting it.

cool ... I used to use situations like this (for the first 7 years or so) to drive my data collections. I'd start what I call an "ad hoc" measurement, for which I have a sheet in my (was using) Excel work book. I would then take INR every second day till my usual measurement so that I could see what happened.

Eg

so when I discovered I did an INR reading (my usual day for INR testing is Sunday).

When nature gives you lemons, make lemonade (or take the time to build data to store that event)

Knowledge is power and power is confidence