Oral Clotting Disorder Treatments
Warfarin
Warfarin is most commonly taken by mouth in tablet form. Warfarin affects clotting by interfering with the vitamin K pathway. The vitamin K pathway is involved in producing several clotting factors, including factors II, VII, IX, and X. All of these clotting factors are needed for normal clot formation. Interference of the vitamin K pathway leads to a reduction in the function of the clotting factors, which in turn reduces the ability to form a stable clot. This results in a blood-thinning effect.
Each person may need a different dose of warfarin. In addition, warfarin interacts with many different medications and is also affected by the daily vitamin K content in a person’s diet (green leafy vegetables contain vitamin K).
Learn more about warfarin interactions with food
Frequent monitoring (weekly to monthly) may be needed to make sure that the warfarin dose is safe and effective. Warfarin typically requires three to seven days to produce an adequate blood-thinning effect. Therefore, patients starting warfarin therapy need some form of heparin for additional coverage to ensure adequate anticoagulation. Heparin is stopped when the blood is thin enough. This therapy is called “bridging anticoagulation.”
Anticoagulation with warfarin is monitored with laboratory testing. The international normalized ratio (INR) is a standardized measurement indicating how long it takes the blood to clot on warfarin compared to the blood of someone not on warfarin. The frequency of international normalized ratio testing varies per person and depends on how stable the international normalized ratio values are and other conditions that vary per person. Warfarin should not be used during pregnancy, as it could cause congenital disabilities.
Dabigatran (Pradaxa)
Dabigatran is a medication used to slow and prevent the formation of blood clots. It is called a direct thrombin inhibitor and prevents blood clots by blocking thrombin (a very important protein involved in blood clotting). Dabigatran is a tablet taken twice a day by mouth. It does not need laboratory monitoring because it has a predictable blood-thinning effect in people who have normal kidney function.
It does not require bridging with heparin, and it is fully active within two to three hours of taking the first dose. It does not interact with most common medications or foods like warfarin does; however, there are certain medications that may affect the way dabigatran works, so it may not be an appropriate option for everyone, including people with kidney problems or liver disease. Dabigatran should not be used in people with prosthetic heart valves.
Rivaroxaban (Xarelto)
Rivaroxaban is a once-a-day oral blood-thinning medication used to treat and prevent blood clots by turning off a specific clotting protein (factor Xa) in the blood. When it is used to treat a new blood clot, it is taken twice a day for three weeks, before switching to once a day.
Like dabigatran, it does not require laboratory monitoring because it has a predictable blood-thinning effect. It does not require bridging with heparin, and is fully active within two to four hours of taking the first dose. It does not interact with most common medications or foods as warfarin does. There are certain medications that may affect the way rivaroxaban works, so it may not be an appropriate option for everyone, including people with kidney problems or liver disease. The use of rivaroxaban is not recommended in people with prosthetic heart valves.
Apixaban (Eliquis)
Apixaban is an oral blood-thinning medication used to treat and prevent blood clots that works like rivaroxaban by turning off a specific clotting protein (factor Xa) in the blood. It is a tablet taken by mouth twice a day. Apixaban does not require laboratory monitoring as it has a predictable anticoagulant effect.
It does not require bridging with heparin, and is fully active within three to four hours of taking the first dose. It does not interact with most common medications or foods like warfarin does; however, there are certain medications that could interact with apixaban and increase the risk for bleeding. As with all blood thinners, this medication should only be taken under the supervision of your doctor.
Call the IHTC to learn more about the best clotting disorder treatment options for you or your child.