Enteric Coating On Aspirin May Interfere With Heart Protection

We now know that daily aspirin therapy helps lower the risk of heart attack and clot-related strokes. Aspirin interferes with the blood's clotting action. If blood vessels are already narrowed from accumulation of fatty deposits and/or and scar tissue, a blood clot can quickly block the artery. This prevents blood flow to the heart or brain and causes a heart attack or stroke. Aspirin therapy reduces the clumping action of the platelets - thereby possibly preventing heart attack and stroke.

Analysis has shown that the minimum dose of 75 mg plain aspirin is the lowest effective dose for heart protection, though most cardiologist are now recommending a daily full-dosage 325 mg aspirin.

Increased aspirin use, however can increase the risk of bleeding and can lead to stomach upset in some people. In order to avoid stomach upset, some people on aspirin therapy are taking the enteric form; the coated aspirin that is supposed to save sensitive stomachs from irritation by dissolving in the small intestine instead of the stomach where most prescription medications are dissolved.

Unfortunately, some new research shows that enteric coated aspirin is not as bioavailable as plain aspirin. This means that enteric aspirin is not absorbed into the blood stream as well as is regular aspirin, which makes it less effective at preventing heart attack and/or stroke. A recent study by Dermot Cox, PHD, at the Royal College of Surgeons in Dublin, Ireland, published in Stroke, showed that levels of thromboxane, a substance that contributes to blood clots, were substantially higher in people who took enteric aspirin compared with people who took regular aspirin.

The study by Cox suggests that poor absorption from the high PH environment of the small intestine may be the reason that enteric aspirin is not as effective as regular aspirin. Cox's study found that this was particularly true in subjects who were heavier.

Thus, people who are on aspirin therapy to prevent heart attack and stroke who may want to consider enteric aspirin to prevent upset stomach or GI bleeding, may find that the enteric aspirin delivers inadequate protection for the heart and brain.

Anyone on aspirin therapy should absolutely not change either the dose or the type of aspirin they are taking without first talking to their physician. But it is important, particularly if the patient is heavier, to pursue discussion with their doctor. You want to be certain that the aspirin regimen you are using is the most effective regimen for you.