If you are one of the millions of Canadians taking low dose ASA (such as Aspirin* and Entrophen*) to help prevent a heart attack or stroke, you should consider getting tested.

When prescribing blood pressure or cholesterol medication, doctors routinely check the patient’s blood pressure or cholesterol to make sure the patient is getting the right dose of medication to protect the patient. Just like any drug, it is vitally important to know if the dose of ASA you’re taking is effective.

Now, when prescribing ASA to help prevent a heart attack, your doctor can measure its effect by using the ASA Effect™ test. Your doctor can then decide to increase or decrease your ASA dose or if additional medication is needed.

To find out if you are at increased risk of a heart attack or stroke because you are resistant to the effect of ASA, ask your doctor about the ASA Effect test.

How does the ASA Effect test work?

ASA is an anti-platelet drug that works to prevent heart attacks and strokes by reducing the production of thromboxane, the chemical that makes platelets sticky.

Although we can’t measure thromboxane directly, we can easily and non-invasively measure 11-dehydro thromboxane B2, its breakdown product (biomarker) found in the urine using the ASA Effect test. In fact, the ASA Effect test is the only Health Canada cleared test that accurately determines a patient’s physiological response to ASA by measuring levels of this biomarker.

A low level of the biomarker in the urine means that ASA is working to reduce thromboxane production. High levels of the biomarker may mean that your dosage of ASA is not effective for decreasing the risk of a heart attack or stroke, and it’s time for you and your doctor to consider increasing the dose or modifying other elements of your treatment strategy.

If you are not sure that the ASA you are taking is working, it’s time to ask your doctor about the ASA Effect test. Why? Studies indicate that individuals with high levels of thromboxane are at increased risk of heart attack, stroke and cardiovascular death as compared to individuals with low levels.

ASA is the abbreviation for Acetylsalicylic Acid
*In Canada, Aspirin is a trademark of Bayer AG, used under license.
*Entrophen is a Registered trademark of PendoPharm.
*ASA Effect and its logo are trademarks of Bescot Healthcare Canada Inc.

If your test results do not demonstrate the desired effect of ASA, your doctor will want to discuss this with you.

Ideally, patients should be on the lowest possible dose of ASA that’s effective. As with other medications and conditions, your doctor will likely review your medical history to make sure that there aren’t some other underlying causes (like high cholesterol) that could be affecting your ASA response. Even something as simple as not taking your ASA regularly or getting your ASA mixed up with another drug can lead to the perception of ASA resistance.

However, numerous studies in medical literature―including new findings from the recent CHARISMA Trial now make it clear that ASA effect is real. It can be measured, and it may be effectively treated by increasing dosage or adding an additional medication. If you’re resistant to ASA and don’t know it or don’t get treated for it, you are at a clinically proven increased risk of heart attack or stroke.

Who is at Risk?

More than 100,000 Canadians experience new or recurrent heart attacks each year. At-risk individuals are candidates for ASA therapy and should be tested for the presence or absence of the therapy’s effect. The ASA Effect test determines the levels of 11-dehydro-thromboxane B2 in urine, which aides in the qualitative detection of the ASA effect.