Could Your Genes Be the Key to Safer, More Effective Heart Medications?

When a physician prescribes medication for a heart condition, whether following a heart attack or to manage a chronic condition such as high cholesterol or hypertension, the goal is clear: to protect your health and prevent future complications.

However, medications do not affect everyone in the same way. Why? Genetics, or DNA, which differs from one person to another, plays a key role in how a medication is processed by the body. It influences both a drug’s effectiveness and the risk of harmful side effects.

Pharmacogenetic (PGx) testing is based on analyzing your DNA, often collected from a simple saliva sample, to anticipate how your body will respond to certain medications. This information allows physicians to avoid prescribing medications that are more likely to be ineffective or to cause adverse effects at a higher than normal rate. [3,4]

Heart disease is common and has serious consequences. Without proper management, it significantly increases the risk of complications and premature death.

In Canada, heart disease remains a major public health issue:

• Approximately 1 in 12 people live with a diagnosed heart condition. [5]
• Every hour, about 14 people die from heart disease. [5]

Imagine this situation: a loved one has just survived a heart attack. Upon discharge from the hospital, they are prescribed several medications, including clopidogrel (also known as Plavix®). Like hundreds of thousands of people in Canada, they take it daily, believing it will protect them from forming new blood clots.

Clopidogrel is a prodrug, meaning it is administered in an inactive form and must be converted by the body to become effective. Without this conversion, the medication simply does not work as intended.

This conversion relies on a liver enzyme called CYP2C19, which is produced based on instructions encoded in our DNA.

The challenge is that our genetic code is unique. There are different versions of the CYP2C19 gene. Some allow for normal activation of clopidogrel, while others result in a defective or less efficient enzyme that does not properly activate the medication. Individuals who carry one or two non-functional versions of the gene are referred to as intermediate or poor metabolizers.

Scientific studies show that intermediate and poor metabolizers treated with clopidogrel have a significantly higher risk of recurrent stroke and other major cardiovascular events compared to those who metabolize the drug normally. In some cases, the risk of death can increase by 76%. [6]

In Canada, approximately 30% of people carry at least one non-functional version of the CYP2C19 gene. This percentage can vary by ethnic background, reaching up to 80% among individuals of Indian descent. [7]

For these individuals, scientific evidence continues to show that replacing clopidogrel with another medication, such as ticagrelor or prasugrel, can reduce the risk to normal levels. [8]

Fortunately, knowing your genetic profile allows physicians to adjust dosages or choose alternative medications to reduce the risk of adverse effects. With appropriate medical follow-up, patients can avoid taking medications that may be potentially harmful or ineffective based on their genetics.

The PGx Cardio Test analyzes how your genes influence the effectiveness and safety of more than 60 medications commonly used in cardiology. Other tests are also available for pain management and mental health, as well as a comprehensive panel covering more than 200 medications. The cardiovascular test costs $349 and may be covered by some private insurance plans.

The use of genetic information to guide treatment decisions is supported by international clinical guidelines and regulatory bodies, including Health Canada and the U.S. Food and Drug Administration (FDA). For several years, these organizations have included pharmacogenetic information in the labelling of hundreds of medications, including many cardiovascular drugs. [9]

Your genes can provide valuable insights, helping you adopt a more personalized approach to heart care and move toward a healthier future. If you are taking medications for cardiovascular conditions, understanding how your genes influence your response to treatment may be an important step toward safer and more effective care. Speak with your healthcare professional to find out whether pharmacogenetic testing may be right for you.