Introduction : Factors for blood coagulation are synthesized in live and vitamin K is required for their synthesis. This is why, by increasing consumption of vitamin K (green leafy vegetables, cabbage, tomatoes, etc.) in diet, the blood becomes thick and if vitamin K is made inactive, blood becomes thin.
Heparin injections used for anticoagulation of blood can be given for few days only. Some patients need anticoagulant medicines for a longer period or for the entire life. for these patients tablets which can be taken orally are more convenient.
Effects : Warfarin makes vitamin K inactive and reduces the synthesis of factors responsible for blood coagulation. So blood remains thin and does not clot.
- After mechanical prosthesis valve replacement
- In case of arrhythmia (Atrial Fibrillation) to prevent ischemic stroke
- Deep vein thrombosis
- Pulmonary thromboEmbolism
Side effects :
- To know the adequacy of anticoagulation level, a blood test – PT INR should be done at a regular interval. In most of the cases, this value needs to be kept between 1.8 – 3.0. Unfortunately this test is not done in many laboratories with perfection. This medicine done in should be taken only under the observation / care of a doctor.
Another medicine with similar effect is Acitrom.
There are many drawbacks of Warfarin :
- Possibility of excessive bleeding.
- Different effects on the same patient at different times – inconsistency.
- Necessity of blood investigation – PT INR at regular intervals. Many patients do not comply due to various reasons.
- Many drug interactions. It alters the effects of many other medicines and vice versa.
- Many food interactions. Various food items can reduce or increase the effects of this drug.
Because of these reasons, persistent efforts are made by scientists to find an alternative of Warfarin. Medicines like Debigatran, Apixaban and Rivaroxaban has been approved for certain indications in last 2 – 3 years. They are safer with less bleeding risk and do not require monitoring of effects by PT INR. On the flip side, all these medicines are highly expensive, there is hardly any antidote for many of them and they are less time tested.