This new use of the drug is based on studies showing that taking as little as half a regular-strength aspirin tablet as soon as a heart attack is suspected and continuing the drug for 30 days can significantly reduce the risk of death, experts said.
Dr. Debra Bowen, director of the drug agency's division for over-the-counter drug products, noted that no one should use the drug for this new indication without consulting a doctor.
A group of cardiac specialists, led by Dr. Charles H. Hennekens of Harvard Medical School, has argued that there is strong evidence from several international studies that aspirin could be beneficial while a heart attack is in progress.
Studies show that aspirin, which is widely available and costs very little, is as effective as specialized drugs that dissolve the blood clots that cause a heart attack and the other drugs that cost hundreds of dollars per dose.
A major international study of heart attacks that involved more than 17,000 patients at 417 hospitals around the world found that aspirin reduced deaths from heart attack by 23 percent in patients who took the drug within 24 hours of the onset of symptoms. And when aspirin was combined with specialized drugs during this early treatment period, deaths decreased by 42 percent.
Since about 50,000 heart attack patients who are hospitalized in the US die from the condition, general use of aspirin within the first hours of the attack could prevent 5,000 to 10,000 premature deaths each year, said Hennekens, who is chief of preventive medicine at Brigham and Women's Hospital in Boston.
Aspirin works against heart attacks by helping to dissolve clots of blood that block arteries and by preventing further blockages. The drug interferes with the production of substances called prostaglandins, which promote the clumping of blood cells called platelets. These cells are essential to the formation of blood clots.