Mechanisms of Action of Acetaminophen

• Status: Completed
• Trial end date: 2012-01-24
• Target enrollment: 0
• Participant gender: All

Summary

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.

• Phase: N/A
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: University of Pennsylvania
• Treatments: Acetaminophen; Aspirin; Ibuprofen

Criteria

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.