The Hemophilia and Thrombosis Center of Nevada

2020 W. Palomino Lane Suite 110

Las Vegas, Nevada 89106

702-385-2702

since May 5, 2008

Last updated May 5, 2008

webmaster RIS

WARFARIN THERAPY

Last month, I had two pulmonary embolisms (one in each lung). The embolisms were caused by a long 16 hour drive while travelling, and not believed to be the result of my body's natural manufacture. I was put on Coumadin and have been on it for 5 weeks.  A few days later, I was diagnosed with cancer of the kidney. It is at the 2.5 cm stage and size, and can be removed. I need to get it out but the surgery is complicated by being on Coumadin anticoagulant due to the embolisms. So, because of the embolisms and the Coumadin treatment, I am told I can't undergo the cancer removal operation on the kidney until at least 6 months from now. It bothers me that I have this cancer in my body and can't immediately get it out.

I am most interested in your opinion as to:
1) How long should a person on Coumadin have to wait before engaging in an operation to remove the cancer?
2) How much risk would it be to stop Coumadin to do the operation less than 6 months considering I have been on Coumadin for 5 weeks?

3) How concerned would you be to stop the Coumadin therapy to do the cancer operation in less than 6 months?
4) Do you know any information source that I could find to assist me with more information on when it would less risky to do the cancer operation?

5) If you were faced with the same situation, what would you do??
I would greatly appreciate your response. Thank you!

We know that the greatest risk of propogation to a pulmonary embolism is within the first month after a deep venous thrombosis.  After that time, we believe that the clot is stabilized to some degree.  Therefore, if surgery or a procedure is required within the first month, bridge therapy with a heparin product is necessary.  After one month, there is little information to help guide our decision making and either heparin may be used while the person if off of warfarin to maintain anticoagulation, or sometimes, in low risk situations, the warfarin may be stopped four days prior to the procedure, the day of the procedure and resumed after the surgery.  In this manner, the patient is not protected for approximately five to seven days.  The risk of a new clot in this period of time under normal circumstances may be smaller.

If a malignant tumor is being considered, then surgery should not be postponed long enough to risk spread or significant growth.  However, elective procedures should be postponed until therapy is complete.

It would be highly likely that the clot is the result of the malignancy, if this is in fact cancer.  Malignancy increases the likelihood of blood clots occurring and may be the initial presentation of a cancer.

My husband had a blood clot in his leg last November and was diagnosed with the Lupus anticoagulant. We have several questions:

1.  Several months ago he had a root canal.  We were initially told by the specialist he would only require about a week of Innohep injections but his protime levels did not come up when he started back on coumadin.  He had to inject himself with Innohep for over a month before the levels returned to a safe range.  We were concerned and asked the doctor but he said all people are different.  We would really like more information since he will need dental work in the future.  Could he have been given a higher dose of coumadin to bring the levels up faster or would this have been dangerous?

With most dental procedures coumadin does not need to be discontinued.  This depends upon the comfort of the dentist.  If it is discontinued, it should be stopped three days before the procedure and resumed at the same dosage as before after the procedure is complete.  With this, usually within a week the level is therapeutic again.  If you have taken increased amounts of vitamin K foods or vitamins then additional coumadin will be needed.  Very large loading doses of coumadin are not of benefit.

2.   Recently he tested high when the protime was done and had to stop the coumadin for a few days and start taking alower dose of coumadin.  He was taking a termporary ten days of Vioxx prior to this but the specialist did not think it would elevate the protime levels.  Could the Vioxx have caused this increase?

Vioxx is known to interfere with coumadin.  Celebrex which is from the same class of drug may also interfere  but to a lesser extent.

3.  The specialist prescribed coumadin indicating the warfarin might not be as effective.  Is this true?

Generic medications may not have the exact efficacy as brand name well studied drugs.  In addition, lots may vary in effectiveness.  Early on when generic warfarin became available, we found more difficulty maintaining a therapeutic INR with generic product.  There is one generic brand that has been well tested and is as effective, however if your doctor writes "may substitute" you do not know what you will be receiving and the INR may vary.  Therefore, we at our center recommend brand name as it is only a small amount more in cost and may result in added safety.

 I was diagnosed with FVL (hetero) in August 2002 after my son was stillborn
at 27 weeks.  He suffered from severe IUGR and I had low blood flow through
the placenta during my weekly ultrasound screenings.  After I delivered, I
was prescribed coumadin for anticoagulation therapy for 12 weeks.  I
unexpectantly got pregnant while on the medication, but only took the
medication for about 1 week after implantation (my best estimate).  I
immediately began anticoagulation therapy with heparin after a positive home
pregnancy test (at about 5 weeks) and a strong heart beat was detected via
ultrasound at 7 weeks.  Unfortunately, the pregnancy was lost at 10 weeks
when a heart beat could not be detected.  There was a chromosomal analysis
completed which came back negative for any chromosomal abnormalities
My question is this....Could taking coumadin preconception have caused my
miscarriage and do what is the protocol for prescribing heparin while trying
to conceive?  Will it increase my chances of carrying a healthy baby to term?

Thanks so much for your feedback

Warfarin is toxic to the developing fetus.  Therefore, typically when one decides to become pregnant, they either do frequent pregnancy tests and discontinue warfarin immediately once pregnant, or they do as we do in clinic, and when you decide you want to become pregnant, begin heparin products and discontinue the warfarin before trying to become pregnant.   Because heparin is not as effective for treatment with persons with heart valves, many obstetricians continue warfarin during much of the pregnancy to protect the mother.  In Europe, warfarin is used during the safer, last part of the pregnancy.  It is the first portion of the pregnancy where warfarin should not be continued.  However, it sounds as though you were not on this medication for long enough for developmental defects to occur.

There has been controversy regarding women with thrombophilia and childbirth.  Some believe that they have a more difficult time carrying to term and heparin is used with some pregnancies to increase the likelihood of normal delivery.  It is possible that the Factor V Leiden mutation you have may be playing more of a role in your inability to carry to term than the warfarin.  I would recommend that you work closely with a hematologist and high risk obstetrician when you decide to try to become pregnant again.

Twenty years ago, while pregnant I was discovered to have Thrombocytopenia.
After about 8 yrs ( after having no medication) I had a DVT, then they
discovered that I had Lupus Anticoagulant, which caused the clot. After 5
years I was taken off Warfarin and put on Aspirin, with in a month another
clot appeared. I am now on Warfarin for life.  What I would like to know
what are the longturn side effects of warfarin?

Warfarin is one of the oldest drugs.  It was first identified that cattle in a field had a bleeding disorder and was linked to the injestion of spoiled sweet clover that was growing in the field.  Scientists isolated the compound and warfarin was discovered.  Initially, a use for the drug was not known.  However with the advent of modern medicine, prosthetic heart valves, treatment of blood clots and heart arrythmias, the indications for its use grew. 

Persons with heart valves require life long treatment with warfarin to prevent stroke.  We have the greatest amount of information on long term usage in these persons.  The risk of warfarin is that of bleeding complications and that is why monitoring closely is so important.  Warfarin has a very  narrow therapeutic ratio, so little changes in diet or medication may affect the clotting tests.  If monitored well, and the INR maintained in therapeutic range, with discontinuation prior to invasive procedures and notification at the sign of any sign of bleeding, it is a safe medication that has been used in individuals for decades.
 

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Last modified: March 02, 2008