Aspirin Coating May Hurt Drug Benefits

Aspirin Coating May Hurt Drug Benefits

December 5th, 2012 // 6:49 pm @ jmpickett

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The coating on aspirin to protect your stomach could camouflage the benefits for some patients, according to a new study. And the finding may influence doctors to prescribe more costly prescription drugs, although the main objective was to test the idea that aspirin does not prevent heart attacks or strokes in some people.

The researchers maintain they did not find any cases of true aspirin resistance in 400 healthy people examined. They instead concluded that the coating on aspirin interfered with the way aspirin entered the body, and this was purportedly noteworthy because this made it tests that aspirin was having a beneficial effect.

When it comes to the potential of false diagnoses of aspirin resistance, the coating could lead to the failure to put someone who would benefit from a cheap and effective drug for cardioprotection, according to Garret FitzGerald, chairman of pharmacology at the University of Pennsylvania and co-author of the study, which was published in Circulation (here is the abstract).

Aside from being cheaper, some of the benefits that uncoated generic aspirin hold for patients include, “avoiding the false call of aspirin resistance,” FitzGerald wrote us in an e-mail. “Psuedoresistance derives from the slow and irregular absorption of the coated form. The cost issue is not a big one except at the national level when you multiply it up by the tens of millions of people who take it.”

Bayer partially funded the study, and as a manufacturer of aspirin, much of which is coated, the drugmaker took issue with some of the study conclusions and methods. A spokeswoman wrote to us saying that “the authors’ suggestion that use of enteric coated aspirin should be questioned, based on these study results, is of concern given the study population and methodology used, neither of which reflect real-world clinical use.”

Bayer maintains the study is less than adequate for several reasons. First, platelet reactivity testing was done in healthy, young subjects – not the typical population for which aspirin would be prescribed for preventing heart attacks. Additionally, the “pseudoresistance” was only seen in testing done after single doses of enteric-coated aspirin. After a week of daily dosing with 81mg of enteric-coated aspiric, the pseudoresistance was eliminated in all patients except one, and that patient was also not responsive to the Plavix bloodthinner.