Common painkiller may weaken Aspirin's heart attack protection

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age between 18 - 55 * Subjects recruited for the "non-smoker group" must be in good health as based on medical history, physical examination, vital signs, and laboratory tests. * Subjects recruited for the "smokers group" will be chronic smokers of at least 4 years duration, but no longer than 20 years duration, who smoke 11-20 cigarettes per day. Smokers must be otherwise healthy as described above. * Female subjects of child bearing potential must be using a medically acceptable method of contraception (oral contraception, depo-provera injection, intrauterine device, condom with spermicide, diaphragm, cervical cap, progestin implant, abstinence, tubal ligation, oophorectomy, TAH) throughout the entire study period. All female subjects must consent to a urine pregnancy test at screening and just prior to the start of each treatment phase of the study, which must be negative at all time points. * Subjects must be within 30% of their ideal body weight. Exclusion Criteria: * Female subjects who are pregnant or nursing a child. * Subjects, who have received an experimental drug, used an experimental medical device within 30 days prior to screening, or who gave a blood donation of ≥ one pint within 8 weeks prior to screening. * Subjects with any coagulation, bleeding or blood disorders. * Subjects who are sensitive or allergic to acetaminophen and/or aspirin, as well as any of their components. * Subjects with documented history of any gastrointestinal disorders, including bleeding ulcers. * Subjects with any evidence of cancer. * Subjects with a history of heart disease, including myocardial infarction, angina, coronary artery disease, any evidence of coronary artery stenosis, arrhythmias, heart failure, having had a coronary intervention or significant irregularities in the EKG. * Subjects with history of peripheral artery disease (claudication, bypass surgery or stent placement in extremity.) * Subjects with a history of stroke or transitory ischemic attacks. * Subjects with renal, hepatic, respiratory, endocrine, metabolic, hematopoietic or neurological disorder. * Subjects with a history of liver disease or abnormal liver function tests (\>2x upper limit normal). * Subjects with any abnormal laboratory value or physical finding that according to the investigator may interfere with interpretation of the study results, be indicative of an underlying disease state, or compromise the safety of a potential subject. * Subjects who have had a history of drug or alcohol abuse within the last 6 months.