UAB Synopsis, Vol. 24, No. 9, March 14, 2005
The UAB Drug Information Bulletin notes that cardiovascular disease is the leading cause of death in the United States, and aspirin is recommended for patients who have known heart disease. Yet, the use of aspirin in healthy people with no known cardiovascular disease remains controversial.
Five randomized trials have examined aspirin use in healthy people: The British Doctor's Trial (BMD), the Physician's Health Study, the Thrombosis Prevention Trial, the Hypertension Optimal Treatment Study (HOT), and the Primary Prevention Project (PPP). All except the BMD trial showed reductions in rates of cardiac events, however, only two (HOT and PPP) included women, and these presented conflicting results about the benefits of daily aspirin in women. No trial showed a reduction in deaths from any cause, but scientists believe the trials were underpowered.
The doses used in the five primary prevention trials varied from 75 mg to 500 mg once daily. The minimum effective dose ranged from 75 mg to 160 mg.
The American College of Clinical Pharmacy and the American Heart Association recommend that individuals at moderate risk for a coronary event take an aspirin daily at doses between 75 mg and 162 mg, unless contraindicated. They defined moderate risk as greater than a 10%, 10-year risk of a cardiac event based on a Framingham score that includes age, total and HDL cholesterol, smoking status, and systolic blood pressure.
The U.S. Preventive Services Task Force recommends that only people at high risk for heart disease discuss risks and benefits of aspirin with their practitioners.
The UAB Health System Pharmacy and Therapeutics Committee recommends people at a 10% or greater risk of cardiovascular disease take daily aspirin at a dose between 81 mg and 162.5 mg. The risks and benefits should be discussed with each patient.
Minimum Effective Dose of Aspirin
Men at high cardiovascular risk: 75 mg
Hypertension: 75 mg
Stable angina: 75 mg
Unstable angina: 75 mg
Acute MI: 160 mg
TIA and ischemic stroke: 50 mg
Severe carotid stenosis: 75 mg
Acute ischemic stroke: 160 mg