Living with Warfarin, INR,

 Before reading this please be aware that I am not a doctor. I am writing this because I have first hand experience of a heart condition that meant I had to be on warfarin for over a year. Please check any information or agree any changes to  medication with your doctor first.

If you have been affected by a blood clot, stroke, DVT (deep vein thrombosis), or heart arrythmia (irregular rhythm) or heart condition such as atrial fibrillation, you might be put onto warfarin (Coumadin). Irregular heart beats could produce turbulence and lead to bits of heart valves breaking into the bloodstream. Blood clots are formed when platelets get "stuck" in the capillary system or the arteries start to harden as they degenerate. Calcium is also needed for them to form.

Warfarin thins the blood by inhibiting the action of an enzyme that converts vitamin K to an active form.
It has a stronger action than aspirin or clopidogrel which inhibit platelet activity. Once you are put on warfarin the level in your bloodstream must be measured at least weekly until you are stable and know your own levels. Testing might then be reduced to fortnightly. The level must not be altered rapidly. It is a bit like steering a barge on the canal. The barge takes a while to respond, if you move the tiller too far it will hit the bank. Blood clotting rates are measured as an INR (Internation Normalised Ratio). A therapeutic dose is normally between 2 and 3, (or 4 if you are waiting for an operation).

Warfarin will have a stronger effect if you take non-steroidal anti-inflammatories like neurofen or aspirin. It might also have more effect if you are on metformin for diabetes. Some anti-biotics also reduce vitamin K levels in the blood. Bromelain which is extracted from pineapple core might increase its effect. Grapefruit or grapefruit juice is an active substance that can increase the effect of medication. High levels of anti-oxidants like vitamin C might affect the level.

More importantly, foods that contain vitamin K will reduce the effect of warfarin. If your diet regularly includes green leafy vegetables such as cabbage, broccoli, lettuce and spinach you might reach a stable level on warfarin without having to make changes, the dose will be higher. But if you change your diet frequently it will be harder to stabilise. Foods that are very high in vitamin K are alfalfa sprouts and watercress. There were times on warfarin that I simply had a craving and ate a whole bag of watercress. It is as if my body needed to stock up again. Green vegetables (and cauliflower, oranges, tahini and honey are also good sources of calcium). Calcium is needed for blood clotting and muscle function. You might be led to believe that you must not eat these foods at all. Taking these foods is not harmful, but stopping them or changing your diet might lead to a change in your INR levels.

Long Term Effects of Warfarin (Coumadin)
Tiredness is a common side effect. My suspicion is that it lowers calcium uptake and leads to energy loss in muscles. Frequent bruising at the slightest knock, break down of capillaries around the eyes and nose, in the legs and all signs of too high a dose for too long. Nose bleeds are another sign of capillary breakdown. A blow to the head could lead to a haemorrhagic stroke (a bleed in the brain). If you have a sudden severe "thunderclap" headache the physician must be informed that you have been on warfarin. The biggest long term risk is osteoporosis. I suspect that the increase in hip and other fractures from falls could correlate with increased numbers of elderly people on warfarin. As long ago as 1975 scientists isolated a substance called osteocalcium from the bones of chicks. Vitamin K acted as a catalyst to start bone formation around this protein framework.



Conclusion
Doctors have to weigh up the benefits of a mediation against the risks of its side effects. In my case I am glad that I took warfarin, unpleasant though it was. It enabled me to have numerous complex heart procedures that led to a great improvement in my energy levels. It is up to you, talk with your own GP or specialist physician.