Ximelagatran is a medication that was considered for approval by the United States Food and Drug Administration (FDA) in 2003. It interfered with normal liver function and because of this, was not approved. It belongs to a class of drugs called anticoagulants, which are used to thin the blood.
The function of ximelagatran is to prevent blood clots from forming. Though blood clots are important in stopping hemorrhaging, under certain circumstances, clots can lead to serious injury or death. Dangerous blood clots can form in the heart in patients with atrial fibrillation or in the large blood vessels in the legs of patients who have undergone major knee or hip surgery. If these blood clots dislodge, they can travel into the brain where they can cause a stroke.
Anticoagulants, including ximelagatran, decrease the risk of stroke by preventing the formation of blood clots. Vitamin K, also called potassium, helps blood to clot by generating a series of enzymes. The final enzyme created in the chain, thrombin, collects red blood cells in a gel made of fibrin. Ximelagatran renders thrombin inactive and stops the body from creating more of this enzyme, effectively preventing the formation of blood clots.
Ximelagatran is different than many other anticoagulants because it comes in a standard dose. Other drugs similar in function are difficult to properly administer because the blood must be thinned enough to prevent the formation of large blood clots but not so much that internal bleeding continues unchecked. Both of these scenarios can lead to the death of a patient, so doctors must perform numerous checks to make sure the dosage of anticoagulants is correct. Coming in a standard dose, ximelagatran would have made it easier for patients to receive treatment at home.
Taken as a pill or oral suspension, ximelagatran begins working within a couple of hours. Other anticoagulants that can be administered by mouth do not start working as quickly as this medication. Though ximelagatran does not remain in the body very long, it is effective enough that it can be administered as two daily doses.
To be effective, the medication needs to be broken down into its active component, melagatran. The liver is responsible for taking ximelagatran and transforming it into melagatran. After an initial study, the FDA determined that ximelagatran was not safe. 6 to 12 percent of patients experienced decreased levels of liver function, and the FDA decided that this was an unacceptable risk for future patients.