Customizing medications to your genetic makeup

6/14/2018 by Dr. Timothy Curry

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Genetics can significantly affect how your body responds to medications. The study of this link between medications and genetics is called pharmacogenomics. Many researchers are investigating how pharmacogenomics can enhance medical treatment and tailor medications to best fit your needs, while minimizing the risk of side effects.

Traditionally, medications have been prescribed based on the assumption that a drug will work approximately the same way in each person, with some factors such as age, weight, sex and medical conditions taken into consideration. But recent research has clearly shown that's not always true. And adjusting doses over time based on response to a medication is slow and challenging.
 
In response, pharmacogenomics — the study of how drugs work coupled with information known about human genes — is being used to tailor medications and their doses for people based on their genetic makeup. This is an important field, because some medications simply do not work the same way in everyone. And genetics may be part of the reason why.

For example, for the pain medication codeine to become active and ease pain, the body must be able to convert it into morphine. About 15-20% of the population is unable to metabolize codeine into morphine due to their genetics. That means the medication can’t do what it's intended to, and those people don't receive the pain relief they need — even if they take the medication exactly as prescribed.

Other drugs that researchers have identified as being influenced by genetics include some used to treat cancer, heart disease, lung disease, HIV infection, arthritis, high cholesterol and depression, among many others. Currently, almost 200 medications have label information about pharmacogenomic biomarkers. Pharmacists and prescribers can use pharmacogenomics to pick the right medications and adjust dosing based on genetics.

In addition to affecting how well a medication does or doesn’t work, genetics also can affect the side effects people experience when they take a certain drug. In some cases, a standard dose of a medication that's usually associated with little or no side effects could trigger a more significant response in someone whose genetic makeup predisposes them to react to that medication. When it comes to strong painkillers called opioids, researchers are working to determine how genetics may play a role in addiction to these powerful drugs.

Researchers exploring pharmacogenomics are investigating how best to identify the genetic variations affecting the way medications work. Perhaps just as importantly, they also are finding ways that information can be conveyed in a timely manner to health care providers who prescribe the medications and pharmacists who dispense them so they can make appropriate choices about which medications to use, based on a person's genetics.

Research in pharmacogenomics remains in its early stages. Eventually, though, it may be routinely used  to help health care providers give patients customized medication in doses tailored to fit their genetic makeup. Ultimately this translates into specific, individualized and effective care for each person.

Dr. Timothy Curry is a Mayo Clinic anesthesiologist and anesthesiology researcher. He also is director of Mayo Clinic’s Center for Individualized Medicine (CIM) Education Program.