Anti-Coagulation Guidelines from AAFP

[ALCapshaw2]

Warfarin Dosing Considerations

excerpted from the American Family Physician Website
www.aafp.org/afp/990201/ap/635.html
JON D. HORTON, PHARM.D., and BRUCE M. BUSHWICK, M.D.

SNIP

Antithrombotic Effect. The antithrombotic effect of warfarin, or the inability to expand or form clots, is not present until approximately the fifth day of therapy. This effect depends on the clearance of functional factor II (prothrombin), which has a half-life of approximately 50 hours in patients with normal hepatic function.

The difference between the antithrombotic and anticoagulant effects of warfarin need to be understood and applied in clinical practice. Because antithrombotic effect depends on the clearance of prothrombin (which may take up to five days), loading doses of warfarin are of limited value.4,12 Because warfarin has a long half-life, increases in the INR may not be noted for 24 to 36 hours after administration of the first dose, and maximum anticoagulant effect may not be achieved for 72 to 96 hours. (i.e. 3 to 4 Days)4

SNIP
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Re-Test Guidelines from AL Lodwick's Dosing Guide calls for waiting One Week or more (to allow INR to stabilize).
AL Lodwick is a retired Registered Pharmacist and Certified Anti-Coagulation Care Provider who used to be active on VR.com

 

[Sarah_Louise]

GET OVER YOURSELF!!
You may have just wrote "Sarah Louise this is for you"
Its pretty clear these posts are aimed at me, im not thick!
Like i've previously said Sorry im not "normal" and follow the "normal trend" every single person is DIFFERENT, not two people on this forum you will find are the same!
To be honest, im really sick of yours and ProtimeNow THINKING you know everything, yes your on anti-coagulants, but does that really give you the RIGHT to critisize and slag off me and my doctors? becuase i personally DON'T think it does!!!!!

 

[ALCapshaw2]

Here is another link to anticoagulation management recommendations from the American College of Chest Physicians for patients who want to understand how anticoagulation works and know the recommended guidelines.

This paper is longer than I care to copy and reproduce here.

I did note that it has guidelines for testing and recommendations for how to adjust dosing for INR's in various ranges outside of the Target Range, including for patients with highly variable responses.

http://chestjournal.chestpubs.org/content/133/6_suppl/160S.full

Pharmacology and Management of the Vitamin K Antagonists*
American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)
Jack Ansell, MD, Jack Hirsh, MD, Elaine Hylek, MD, MPH, Alan Jacobson, MD, Mark Crowther, MD, and Gualtiero Palareti, MD

 

[normofthenorth]

Play nice, folks. Sarah Louise, this information is useful for many of us, even if Al and Protimenow have been too tough on you and your medical practitioners (as I agree they have been). Leaving you out of the equation completely, lots of us have dealt with doctors who haven't understood and internalized these guidelines. (That's why the associations issue the guidelines!)

The first guideline should actually be even stronger, IMHO, since Warfarin actually has a PRO-thrombotic effect (it PROMOTES clot formation!!) in the first ~48 hours of administration, based on a study I recently found, read, and linked here somewhere! That's why it's important that injections of Heparin or Lovenox continue for 2 or 3 days AFTER the beginning of oral ACT administration. And also after "bridging", when a long-time ACT patient has interrupted ACT (and substituted Heparin or Lovenox) for a surgery, etc.

 

[Protimenow]

You know, Al, I'm often surprised at how much alike mammalian systems really are. It's funny - warfarin was originally tested in dogs and other animals because their systems responded in almost exactly the same way as it did in humans. In fact, the effect of the chemical that became known as warfarin was discovered because this was a long known veterinary problem -- people whose cows ate fermented clover died from internal bleeding. And animals that were being castrated bled to death. It took some scientists at the Wisconsin Alumni Research Foundation to find the cause and develop a form of the chemical that can be used therapeutically. High doses were used to kill rats (until some rats developed a resistance to its effects). I'm sure that if it's given to horses, pigs, or most other animals, it would have the same effect on them that it does on humans.

When my dog gets sick, the vet gives her the same antibiotics, in smaller doses, than humans take if we get sick. My dog started acting strangely at night, and he gave her some kind of doggy antidepressant (a smaller dose of what humans get). The vet has prescribed baby aspirin and pepto-bismol for my dog. Functionally, it's amazing to think how much alike human and animal systems really are.

To think that there's a major difference in basic biological systems from one human to another is a vanity that can be very costly. Personally, if I'm told that certain of my basic biological systems was dramatically different from everybody else's, I'd probably want to learn more about it, rather than blindly putting my life into the hands of someone who I want to believe knows this is right.

 

[catwoman]

Al:
Thanks for posting thse links and articles.
When I saw Al's post and the first response the other day, I was very perplexed.
I've been on thie site for 7+ years, and Al has posted very useful information.
I have a notebook of articles about warfarin and home-testing, including a bound copy of Al Lodwick's articles from his old website, www.warfarinfo.com (no longer on the web, unfortunately).
The more I know about warfarin and my condition, the more I can team up with my doctors.

 

[ALCapshaw2]

Thanks for the kind words Marsha.

I've known about those sources for some time but had never searched for them on the internet.
I decided it was time to see what I could find and post the links for anyone interested in learning about anticoagulation
and the recommended management protocols for the vast majority of patients.
The Physician who oversees my Coumadin Clinic (3000 patients managed by 4 CRNP's who I believe are also Certified Anti-Coagulation Care Providers) showed me his 1 inch thick copy of the CHEST guidelines. Several members have cited the AAFP guidelines in the past.

(I see that you attempted to send me a PM but my mailbox is overloaded.
You can e-mail me through VR if you like.)

 

[Herb M]

Al, I read most of the web site that you posted. It was useful, but some of it was beyond my understanding. I did print out the table of adjustments to INRs that are not in range. It is not much different that the dosing chart that I used for a few years. I wonder how many doctors have read this. I think very few.

Thanks for posting it.

 

[Protimenow]

A lot of this stuff IS quite deep. What's probably most important IS the dosing chart.

BTW: I saw a NOVA last night about nano technology - and there was a segment about the DNA test for reaction to Warfarin. It looks as if the researchers probably are getting a handle on the genetic markers related to warfarin sensitivity. At the end of this segment, the doctor on screen actually came up with a dosage. As far as I can tell, this is a STARTING dosage -- it doesn't change the need for testing, because there are a lot of factors in addition to genetics that can change a person's INR.

The show didn't mention how much this genetic testing cost, or whether the benefits overrode the cost. It would certainly be nice to know if there's a test that can confirm the difference between a person who has a genetic marker for some really aberrant reactions to warfarin from just plain bad management.

 

[Duffey]

I saw that same program. The next time it airs, I'll try to post the time and date.

 

[Protimenow]

FWIW - the show was Nova and the subject was nanotechnology. A subhead was something about making everything small.

I wonder if they've got it online somewhere.