The U.S. Food and Drug Administration on Wednesday approved the blood-thinner Brilinta (ticagrelor) to cut the risk of heart attack and death in patients with acute coronary syndromes, or ACS.

ACS includes conditions such as a heart attack, which could result from a low blood flow to the heart.

Brilinta, made by the pharmaceutical company AstraZeneca , prevents new blood clots from forming and maintains the blood flow in the body, thus preventing another cardiovascular event, according to the FDA.

This move on the part of the FDA will make Brilinta a rival to the drug Plavix, which is the second-best selling drug in the world.

The FDA will require a box warning stating the drug's effectiveness when taken with aspirin. That box warning will tell providers and patients that like other blood thinners, Brilinta increases the rate of bleeding and can cause significant, sometimes fatal, bleeding. People in the clinical trial for Brilinta have reported that bleeding and difficulty breathing, the FDA said. 

In clinical trials, Brilinta was more effective than Plavix in preventing heart attacks and death, but that advantage was seen with aspirin maintenance doses of 75 to 100 milligrams once daily, said Dr. Norman Stockbridge, director of the Division of Cardiovascular and Renal Products in the FDA's Center for Drug Evaluation and Research.

Reuters reported that AstraZeneca shares jumped 3.5 percent on Thursday because of the FDA's approval of Brilinta.

Industry analysts said the drugmaker will still have to try selling the product in the world's top market because of its interaction with aspirin and the expected launch of cheap generic copies of Plavix next year, according to Reuters.