What is the average time it takes for Warfarin to have any effect?

[WayneL]

Whilst attempting to correct her INR's, my daughter says it takes three days for the dose given today to have any affect .

Is this right?

If so,given her currently unstable INR's, should we be looking at getting her meds changed to HEPRIN or something similar?

[tassie]

I think they say something like 48 to 72 hours and 3 days is a common time they trot out. But do they really know? They also say we can't possibly tell when our INR is too high or too low by how we feel.

[pumpkincake]

Wayne...my doc today said up to 3 to 5 days.

[jetjetjet]

my warfarin is changed ,every 3 days as soon as they get my inr reading because im all over the place most of the time , but my plaqenil is always the same dose. 400 ml per day , last 3 inrs were 3.9- 2.8 - today 1.9 ??? they are scratching thier heads ,my target range is 2.5 to 3.5, i knew it was off i was feeling sluggish.it will be 5 s and 4 s next 3 dayson the warfarin , ill test again on thursday morning----------------- just my wacko system--------------- jet

[Renae]

It takes 72 hours to hit its max level, but it does start working as soon as we take it.

I guess i am the devils advocate, I have had a dx of aps, lac, protein defeinitcy, lupus sle, ms all for 16 years and I feel no different when my inr is high or low.

[Manofmendip]

Changes to Warfarin dose can take 48 hours or so to have an effect, in my experience. My Haematologist told me not to change the dose unless there is a definate trend up or down over a few days. he said that trying to micro-manage INR, (i.e. changing the dose every day or so) is wrong and will result in always over or under correcting.

Best wishes.

Dave

[WayneL]

Thanks, All.

I guess that I accept the general consensus on average time is 3 days to max effectiveness.

This poses another few questions then;

If your INR's are unstable, would it not be unreasonable to say that Warfarin would be working from behind as a catch-up measure, rather than actually controlling the INR?

Also, would Heparin / Clexane work more efficiently or rapidly thus allowing more accurate control of the INR level?

These are some of the questions that have emerged to me from your replies.

Thank you.

Wayne L

[Herb in reply to WayneL]

Heparin does not affect the INR. It works differently to achieve the same effect. I have been led to believe it works instantly. However for many people it is difficult to be on it long term due to the side effects.

Personaly I found changes to warfarin dose seemed to have an effect up to a week and the INR can take a long time to settle down. For example my INR was 6.2 and the dose was reduced to 6, and my INR dropped... but it dropped about 8 days later!

If they dose is constantly fiddled with the INR will not stabilise.

it is possible once her disease is stable the antibodies will not be around so much to cause fluctuations in the INR.

[WayneL in reply to Herb]

Hi, Herb.

It seems to me that my daughter, having been on Warfarin for a very long time, has slowly developed what medical people call "Warfarin failure", where the body has generated a resistance to the effect of Warfarin.

If this is the case, then it would seem reasonable to seek an alternative.

I agree that constant changes to levels of meds cause havoc with the INR's, but what do you do when the dose remains the same but the levels wander all over the place?

Apparently, the effect of Heparin takes only a few hours as opposed to a couple of days (average ) for Warfarin.

She has been stable for a considerable period, some 13 yrs prior to her recent abnormal flare-ups.

We are looking into some alternatives with the help of her specialist and hopefully soon, we will have some answers.

Thanks

Wayne L

[Lesley_D]

I have my INR checked weekly, as also not been able to regularise it over the last year (how long I have been on warfarin). Over a week my INR can change dramatically much the same as everyone here says, however, over the last month, it has shown to stablise and has stayed between the 3 & 4 of my range. Having said all this, it takes little to upset the applecart, from a cold, chest infection, diet, etc.I guess it depends on how much your daughters INR is fluctuating, is she going wildly out of range? Does she feel diffierent if her INR is totally out of whack? Maybe we can all overcheck our INR and not give the warfarin chance to work, and other times the docs/nurses don't listen to us when we know it is wrong.

Anyhow, I do hope your daughter is ok, warm wishes to you all.

Smiles

Lesley

[GinaD]

I'll share my experience, but I am no hematologist. I can only say what works for me:

When I was first put on warfarin in 1986 it was in response to a bunch of DVTs attributed to a sky high platelet count (800K.) My doc at that time put me on an alternating dose of warfarin (a 2.5 mg variance every day'), "I know you're an intelligent and careful patient so I can trust you to write down your dose every day in a notebook. Studies have found that in some people an alternating dose over-rides the body's attempts to compensate for warfarin's blood-thinning actions." I have no idea if this was a true statement or not, but my INR was very stable.

After my platelet count dropped, the warfarin was discontinued for a 10 year interval, then re-started at a constant dose. My INR was again all over the place. I shared the story of my previous luck with alternating dose, we tried that, it worked and I've been mostly stable ever since. Currently I am transitioning up to a higher INR, but for more then 5 years I have been very stable by taking 7.5 mgs, 5 days a week and 5 mgs on Sat. and Wed.

For what its worth . . .

Gina

[lucky1]

Warfarin is supplied in two formats, tablet and soluable.

The tablet form Coumadin has a 72 hour half life. - ie it takes 3 days to reach its peak in the body then dissapates by half every 3 days post that.

The soluable form Clexane has a 12 hour half life - this is why for the best coverage with this drug should be 2 shots per day 12 hours apart

A stable INR is one that is adjusted to you which for a common INR reading of 3 can mean so many different dosages between different people, the dosage whilst important it is ony the key. the INR is what is very important

[Sue2803]

My INR never seems to be stable. Have it checked weekly at the mo because it seems to go from 1.4 to 4.3 for no apparent reason, and always changing my warfarin, but doesnt ever seem to stabalise.

[BJF325]

I agree with Gina, as mine is more stable when the dosage is alternated. When I was on a dose of 7.5 per day it was up and down, then gradually became to low. I am now on an alternating dose and it is stable. I can tell when it is to low or to high.

[tassie]

Lucky I'm sorry but I need to clarify that warfarin (coumadin and marevan and possibly other brand names) is a completely different drug and works in a different way to clexane and the other heparins.

Presently warfarin is given by tablet and is checked by measuring the INR or clotting time.

The heparins are given either by sub cutaneous injection or via a drip and they don't alter the INR as they work in a different way to thin the blood.

Wayne I have been wondering the same thing about whether clexane might be a better option but this alternating dose idea is interesting. At the moment I am alternating 3mg and 3.5 mg on alternate days but my INR is unstable. so maybe I need to have a bigger variation and only lower on 2 days?

[WayneL]

Hi.

Apparently, she has been tried with an alternating dose, but it didn't have any noticeable effect for her INR's.

I am beginning to suspect that she also, is a Warfarin failure, however, it is currently the best method we have.

As soon as we see the specialist (next week) I'll enquire as to whether there is a better alternative for her.

Over the past month or so her range has gone from1.9 to 6.8, so I can understand her frustration, as we have tried everything we can to keep within her range.

Thanks,

Wayne L

[k7pbx]

4 days for me.