Ticagrelor is a medication that prevents blood clots. It is a member of a class of drugs known as antiplatelets and is effective at preventing clots in large arteries, including the aorta and pulmonary blood vessels. This anticoagulant was tested and shown to be more effective than many other drugs but has not been approved for use by the United States Food and Drug Administration (FDA). In the European Union, the medication is available.
Like other antiplatelets, ticagrelor works by preventing platelets from joining together. Different types of antiplatelets affect platelets in different ways — by inhibiting their creation, preventing them from aggregating, or stopping them from bonding with certain enzymes that help them clump together. Ticagrelor is chemically distinct from other antiplatelets. The effects of this medication are also reversible, unlike many other antiplatelet drugs.
In initial studies, ticagrelor was tested against a similar drug called clopidogrel. Ticagrelor was found to act more quickly than its competition. Deaths due to blood-clot related problems, such as stroke and heart attack, were also lower. The experiment was double-blind with 18,624 patients.
Despite the positive results of the initial study, the FDA did not approve ticagrelor for use in the United States. In their own study, the FDA tested the medication using about 1,400 patients and did not find the same result. In the FDA study, patients were more likely to experience a fatal cardiovascular problem while using the ticagrelor. Another reason that the FDA did not approve this medicine is that it causes more problems with bleeding than clopidogrel, a result which was observed by both studies. This posed a risk to patients who needed to undergo surgery, though that problem could be eliminated if the medication was stopped 5 days before surgery.
It not known why the results of these two studies showed opposite results, though the manufacturer of ticagrelor has suggested that an aspirin dose, which is used alongside ticagrelor, may have been administered incorrectly in US patients. Despite the poor performance of ticagrelor in the FDA study, the FDA’s advisory committee voted 7 to 1 to approve the medication for use in the United States. In December of 2010, however, the FDA declined to do so. Another study may be conducted by the manufacturer in order to reapply to the FDA.
