How your genes can lower the chances of Carvedilol side effects

How your genes can lower the chances of Carvedilol side effects

Carvedilol is a common prescription given to help lower blood pressure. However, determining whether carvedilol is the right medication for you, at what dose, and whether it will cause adverse side effects can be a long, drawn-out process of trial-and-error. Not more than a couple of years ago, this would have been you and your physician’s only choice. Thankfully, the advent of personalized medicine technology can now predict how your body will react to carvedilol and help you and your physician determine immediately whether carvedilol is the right medication for you, and at what dosage it will be the most effective while causing the least amount of side effects.

Treating high blood pressure with Carvedilol, then and now

To illustrate the difference between traditional and personalized prescribing, consider the case of our patient Adam – a 62 year old grandfather of three with a history of high blood pressure that his physician Dr. Smith is managing with carvedilol.

Traditional Treatment Strategy

  • Started Adam on standard dose of Carvedilol
  • At a follow-up visit, Adam’s blood pressure went down, but he complained about experiencing episodes of severe dizziness shortly after taking his medications. So Dr. Smith decreases the dosage of Carvedilol.
  • At a second follow-up visit, Adam’s blood pressure remained under control, and his side effects subsided to a more manageable level.
  • Adam gets back to his life!

Personalized Treatment Strategy

  • Before treatment, Dr. Smith ordered predictive drug response genetic testing for Adam to help determine treatment plan.
  • The drug response test showed Adam carries a variation of a drug-metabolizing enzyme that makes him much slower at processing and eliminating Carvedilol from his body.
  • Dr. Smith decides to treat Adam with a lower Carvedilol dose.
  • Adam gets back to his life!

Even though both treatment strategies resulted in Adam returning to his life as normal, traditional “trial-and-error” prescribing methods means that Adam and Dr. Smith both have to spend time on multiple follow-up visits, and worst of all, Adam had to endure a period of uncomfortable and possibly dangerous side effects before the right dose for him was found. Personalized prescribing using a simple, painless drug response test can save both Adam and Dr. Smith time from follow-up visits, and most importantly, find the optimal medication and dosage for Adam right away.

How does a drug response test help my physician and I optimize my medication?

To answer this question, we have to look at how Carvedilol is metabolized, or broken down, in the body. Carvedilol is metabolized and eliminated from the body by the liver enzyme CYP2D6, which is encoded by the conveniently named CYP2D6 gene. CYP2D6 is a very important enzyme because it’s responsible for metabolizing around 20-25% of all known drugs. CYP2D6 is also important in determining your individual response to medications because many of us have differing variations of the CYP2D6 gene that profoundly affects how active this enzyme is. And this variability affects how effectively Carvedilol is processed and how severe the side effects you experience are. For example:

  1. Ultrarapid metabolizers:

    If you carry a CYP2D6 genetic variation that causes the CYP2D6 enzyme to be more active than the average population will break down Carvedilol so rapidly that it will not have stayed in the body in its active form long enough to achieve a therapeutic effect.

    Result: standard doses are ineffective for ultrarapid metabolizers

  2. Poor metabolizers:

    On the other hand, if you carry a CYP2D6 genetic variation that causes the CYP2D6 enzyme to be less active than the general population, your body will metabolize Carvedilol at a much slower rate. And as a consequence, the risks of side effects, such as dizziness, fatigue, and diarrhea go up.

    Result: standard doses cause adverse side effects for poor metabolizers

Looking at variations in the CYP2D6 enzyme can predict how you will respond to carvedilol, and if you will experience adverse side effects.

Personalized medicine has evolved rapidly in the past decade, and predictive analysis that determines your individual response to Carvedilol is now available. Drug response tests such as GeneYouIn’s PillCheckTM can help to determine 1) the optimal medication dose and 2) the likelihood of side effects occurring.

Next steps

If you would like to learn more about other classes of high blood pressure medication, please check out my other blog post: “What is the best blood pressure medication – part I”. As always, please share this article with your friends and family if you’ve found it to be useful, and make sure to follow GeneYouIn on Facebookand Twitter, or register for our newsletter to stay up to date on all the latest research in personalized medicine!

Image used under the Creative Commons 2.0 License, photo taken by Bernard Goldbach.

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