Updated: Mar 11, 2005

How much aspirin should one take?

While not able to give medical advice, I note many people are taking different dosages of aspirin to reduce the risk of heart disease. I spent about an hour reading the literature to determine what research suggests, as opposed to what one reads in the popular press.

Full strength aspirin every other day: Article on is the original study that started the idea. In that study, a regular full strength aspirin (not a baby aspirin) taken every other day reduced the risk of heart attack by 55%. The second article is a current one, recognizing that there are side effects to aspirin like gastritis, so if you are not at risk for heart attack, it isn't worth taking. The third article is one where lower dose aspirin was used, but it only says higher dose is more effective. I remember reading an article that said it is full strength aspirin that gives the most important anti-clotting effect. To get the anti-clotting benefit which reduces the risk of heart attack, my recollection is the article stated that one must take full strength aspirin AT LEAST two times a month.

Baby Aspirin every day: Study published in 2001 of 4,500 people at high risk for heart disease (100mg per day) reduced the risk by 44%. See Article 4 below.

ARTICLE 1: Volume 336:973-979 April 3, 1997 "Inflammation, Aspirin, and the Risk of Cardiovascular Disease in Apparently Healthy Men", Paul M. Ridker, M.D., Mary Cushman, M.D., Meir J. Stampfer, M.D., Russell P. Tracy, Ph.D., and Charles H. Hennekens, M.D.

325 mg of aspirin on alternate days - 55.7% reduction in risk of myocardial infarction, 543 previous infarction and 543 control men randomly assigned aspirin or nothing

ARTICLE 2: Z Kardiol. 2004 Mar;93 Suppl 2:II33-II36. The latest word on aspirin:

If an annual risk of coronary heart disease of </= 0.6% exists, aspirin is normally not indicated; for a risk of 0.7-1.4% the facts should be discussed with the patient. If a risk of >/= 1.5% exists, aspirin should be given.

ARTICLE 3: Am J Cardiol. 2003 Oct 1;92(7):843-5. Influence of aspirin on inflammatory markers in patients after acute myocardial infarction. Solheim S, Arnesen H, Eikvar L, Hurlen M, Seljeflot I.

[main point is that 160mg/day is better than lower dose] The aim of this study was to assess the influence of aspirin on selected inflammatory markers in patients recovering from acute myocardial infarction (AMI). Patients participating in the Warfarin Aspirin Re-Infarction Study-II were randomized to either aspirin 160 mg/day or aspirin 75 mg/day + warfarin, or warfarin alone after AMI. After AMI, aspirin 160 mg/day was associated with significantly lower levels of high-sensitivity C-reactive protein and tumor necrosis factor-alpha than warfarin alone over 4 years. However, the same levels were not predictors for clinical end.\

ARTICLE 4: Lancet 357: 89, 2001

For more references and comments on aspirin, click here.