A clinical trial involving 18,000 patients showed that major bleeding events occurred at the same rate with Pradaxa® as with warfarin.
The U.S. Food and Drug Administration (FDA), however, said that because of a number of factors that can influence these study results, "a simple comparison between Pradaxa® and warfarin with respect to the numbers of post-marketing reports of bleeding is of limited value."
An important difference between the two drugs is that an antidote exists to stop the bleeding in warfarin patients, but there is no antidote for excessive bleeding in Pradaxa® patients.
Other differences include:
- A clinical trial comparing the risk of stroke in Pradaxa® and warfarin patients showed that 35 mg tablets of Pradaxa® reduced the risk of stroke 35% more than warfarin.
- Pradaxa® patients have no need for regular blood tests, unlike warfarin patients. This is because the two agents work differently in the body.
- Pradaxa®, unlike warfarin, can be taken with or without food and you don’t have to limit your diet in the same way you do while on warfarin.
- Different mechanisms of action. Pradaxa® is a direct thrombin inhibitor. It works specifically on thrombin (the blood’s main clotting agent) to prevent the formation of clots. Warfarin, by contrast, is a vitamin K antagonist. Warfarin interferes with vitamin K, which is required to form clots.
The latter difference, a different mechanism of action, is why there is a way to stop bleeding in warfarin patients and why there is not a way to do so in Pradaxa® patients. This puts Pradaxa® patients at a higher risk for death by internal bleeding.