February 2016


Aspirin Sensitivity and Resistance

Since the 1970s, doctors have been recommending that people, especially men, who are at increased risk of coronary heart disease take a preventive aspirin daily. Most have focused on the low dose of 81 mg, although there have been suggestions that 162 mg is more effective. A recent study in the heart journal Circulation (3) examined the phenomenon of why some people do not benefit from the daily aspirin in terms of prevention. It has long been thought that to protect the lining of the stomach from the erosive effects of aspirin, the aspirin should have an enteric coating that slows the absorption of the aspirin until it gets past the stomach. It was thought that between 5 and 40% of the population was aspirin resistant, and those were the people who were not benefitting from aspirin use as a preventive. The investigators could not find aspirin resistance, but did find a lack of aspirin absorption due to its coating.

Since there is still concern about protecting the stomach from aspirin, perhaps the 162 mg dose (or two of the 81 mg tablets) taken in the enteric-coated form might be a solution. It is difficult to find the 81 mg aspirin that is not coated, and bleeding from aspirin is still a concern.

Interestingly, in a small study performed in Texas (4), it was found that chewing an uncoated 325 mg aspirin for about 30 seconds, if a heart attack occurs, is the fastest and most effective way to get the platelet blocking effect of aspirin into the circulatory system.


(3) http://circ.ahajournals.org/content/127/3/377.abstract?sid=c86a6678-7a5d-4b5d-8091-a794e6f148fd

(4) http://www.health.harvard.edu/fhg/updates/update0505a.shtml