Understanding sources of variability in human drug dosing is important to the beneficial and
safe use of any drug. Understanding and applying the science of individualizing a drug dose
to a patient is called precision medicine.
Aspirin is one of the oldest most utilized medications for its ability to lower fever,
relieve pain, and to reduce the stickiness of platelets (tiny blood cells that help your body
form clots to stop bleeding. Aspirin dosing is currently the same for all patients and is not
individualized. In the last century, aspirin has shown benefit in reducing cancer, stroke,
and preventing cardiovascular events after one has already had a heart attack or stroke.
Previous human studies have not found consistent positive effects of aspirin when dosed by
body weight. Therefore, how should aspirin be dosed in 2019? Aspirin resistance is the
failure of aspirin to reduce platelet stickiness and thin the blood and most importantly, is
associated with higher risk of heart attacks and strokes. Aspirin resistance may occur due to
not taking aspirin on a regular basis, differences in how platelets behave in some persons,
use of over the counter pain medicines like Motrin®, reduced amount of drug in the body,
and/or a lack of being able to predict a dose for a certain individual.
To find out the best way to dose aspirin, the investigators propose to study healthy
volunteers (persons without any known disease) with different ages and body sizes to see if
aspirin blood levels are tied to platelet stickiness. This information will be used to
mathematically build a computer-based picture of aspirin dosing that will help physicians
pick the best dose of aspirin for each patient. The investigators will then extend studies
for the aspirin dose estimator to be used in other countries in people with heart problems
and stroke, recording future events in a randomized (i.e., coin toss) manner, to determine if
the ability of the aspirin dose estimator to prevent future heart attacks and stroke compared
to people receiving aspirin doses that were chosen without the estimator.