This research study investigates whether the ability of aspirin to reduce the risk of heart
attacks may be diminished by the administration of acetaminophen. Patients who have heart
disease are often prescribed aspirin because of its unique ability to permanently prevent
platelets from aggregating and forming a blood clot. Such blood clots cause heart attacks
when they form in a blood vessel that supplies the heart with oxygen rich blood. Some of
these same patients also take acetaminophen everyday for relief from arthritis pain. Higher
doses of acetaminophen may also have the ability to prevent the platelets from clotting,
however only temporarily. Therefore, this study evaluates whether the timing of the
administration of acetaminophen (before or after aspirin) interferes with the permanent blood
clotting effects of aspirin.
The primary hypothesis is that acetaminophen given two hours before aspirin will antagonize
the effects of aspirin, while reversing the order of administration will not.