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KOTA Territory NewsAspirin's Heart Benefit Muted When Coated

Aspirin's Heart Benefit Muted When Coated



By E.J. Mundell, HealthDay Reporter
THURSDAY, May 9 (HealthDayNews -- They've been prescribed by doctors for years to reduce risks of first or second heart attack in patients with cardiovascular disease, but a new study is raising concerns that low-dose, coated aspirin might not be as potent as once thought.
"At low doses of 75 milligrams, a significant percentage of people are not receiving sufficient aspirin" to lower their cardiac risk, study lead author Dermot Cox, a pharmacologist at the Royal College of Surgeons in Dublin, Ireland, said in a statement.
In fact, his team found that a normal-weight adult had a 20 percent chance of receiving inadequate cardiac protection from the coated pills, with that number rising even higher among overweight and obese patients.
The findings were reported Thursday at the American Heart Association's annual conference on Arteriosclerosis, Thrombosis and Vascular Biology, held in San Francisco.
Millions of Americans with either a history of cardiac problems or cardiovascular risk factors are currently on daily low-dose aspirin therapy to lower their chances for heart attack or stroke. Because aspirin is linked to stomach ulcers, most take aspirin in a special "coated" form that resists being dissolved in the stomach but is absorbed in the colon instead.
Most experts assumed that this coating would not hinder the overall absorption of aspirin by the gastrointestinal tract.
However, as a matter of routine, Cox's team was asked

by the Irish Medical Board -- Ireland's equivalent of the U.S. Food and Drug Administration -- to test coated aspirin for its "bioavailability," which is required of all over-the-counter drugs sold in Ireland.
In their study involving 23 volunteers, the Irish researchers measured blood levels of a chemical called thromboxane as an indicator of aspirin's absorption and its effectiveness in reducing the formation of dangerous blood clots. The lower the level of thromboxane, the better aspirin was working.
They found that plain, uncoated, low-dose (75 mg) aspirin reduced levels of thromboxane to a healthy 0.28 nanograms per milliliter (ng/ml) of blood. In contrast, Caprin, an equal-strength brand of coated aspirin, lowered thromboxane to just 2.24 ng/ml. Two other brands of coated aspirin, Nu-Seals and Protec, reduced blood levels of thromboxane to ineffective levels of 2.75 ng/ml and 5.5 ng/ml, respectively, the study said.
"I think this is an astounding surprise," said Dr. Richard Stein, a spokesman for the American Heart Association and associate chair of medicine at Beth Israel Hospital in New York City. "I had always made the assumption that the [coated] pill dissolved and was absorbed," he said.
Although the study was conducted using commercial brands of aspirin available in Ireland, Stein said the coatings are formulated much the same everywhere, "so I would imagine that the data in the U.S. with these would not be much different."
"I would be surprised if this didn't become an issue for us to look at," he said. "We know that some patients don't show an adequate effect of aspirin, and we've called them 'aspirin resistant' patients. But I think that some of that will be explained by this."
Both Cox and Stein agree that the reduced absorption of daily coated aspirin may be even more of a problem for the overweight and obese, since they require more aspirin than normal-weight patients to achieve the same heart-healthy goals.
Although the study is preliminary, Stein believes it could change

[Irving]

holy moly this is amazing information!!! i wonder if all the tests done in the past that showed low dose aspirin reduced cardiovascular risk was with coated or non-coated aspirin

[Obesity Discussion]

Incredible study results, this makes a huge difference. I am so glad you shared this with us, thank you!

[cardinarky]

From personal experience, I can tell you that the aspirin therapy is good.
I had a coagulation problem with my blood for years. I had a heck of a time when a blood sample was required. The blood would plug the needle and multiple attempts were required to get a suitable sample.

It is very common for doctors to completely under-prescribe medication dosages when dealing with obese patients. They used the standard 150# male body for dosage recommendations.
I was told about 10 years ago to start with the 81mg "Bayer" coated aspirin to lower my opportunity for various circulatory problems. The kicker is doctors don't think like engineers. They have "scale-up" blindness because they have only one body size in their textbooks.
On all medications it is a good idea to divide your weight by a rule of thumb 150 and then multiply the prescribed dosage by the resulting fraction.
For example, I weigh 305 currently so 305/150 = 2 for all practical purposes. So any OC medication I would take 2x the recommended dosage to cover the body mass/volume variation. Unfortunately this can't work for prescription medications because you will run out in 1/2 the time that the scrip is written for.