What Drugs are Safe and Effective for You?

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This article will explore clinical pharmacogenetics (PGx), the application of genetics to prescription medicine. I hope to give a general overview of the field, explain what the benefits of PGx are, how the testing is done, and how you can get tested.

This article is for use of Advanced Genetics Lab, which aims to personalize medicine and improve treatment decisions. The mission of the company is to reduce adverse drug reactions (ADRs) which are estimated to kill more than 100,000 Americans each year, making it the fourth leading cause of death in the United States (Lazarou et al., 1998). We hope to spread awareness of PGx testing and believe it has a great potential to help patients.

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What Is Pharmacogenetics?

Both our bodies, and the world we live in, are made up of small building blocks called molecules. These molecules interact with each other to cause important changes. When a person takes a medication, the molecules of that person interact with the molecules of that medication to produce an effect. However, not every person is the same, and the effect one person gets from a medication might be quite different than the effect another gets.

Pharmacogenetics testing examines an individual's genes for their ability to metabolize medications. Using a sample of a patient's DNA, genetic tests are run to determine the individual's genotype. These tests target specific segments of the genome that are significantly involved in the metabolism of commonly prescribed drugs. By understanding the genes of an individual, we can predict the effects different drugs will have on that person.

Codeine as an Example
Codeine is one of the most commonly prescribed opiates (Narcotic Drugs, 2014). It works to relive pain by being converted into morphine by the cytochrome P450 enzyme CYP2D6 in the liver. Not everyone's CYP2D6 is coded exactly the same. Due to these genetic variations, there are corresponding differences in the metabolic function. A patient can be a poor metabolizer (PM), an intermediate metabolizer (IM), an extensive metabolizer (EM), or an ultra-rapid metabolizer (UM). This is the example that Russ Altman uses to explain PGx personalized medicine in his Ted talk (below).

• A CYP2D6 EM has normal metabolic function, and benefits from the standard dose of codeine as expected.
• A CYP2D6 PM has little to no metabolism of codeine into morphine, and thus does not get pain relief from the medication.
• A CYP2D6 IM has reduced conversion from codeine to morphine and therefor has reduced pain relief
• A CYP2D6 UM has greater than usual metabolism of codeine to morphine and could be at risk of serious side effects from a high dose of the medication

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Why Get Tested?

Now that we know a little bit about what pharmacogenetics is, what are the different reasons that someone might want to know their ability to metabolize drugs?

To determine the effectiveness of a medication before taking
A patient, or a physician, might request a PGx test to determine what the best medication is before prescribing to insure they use the most effective option. This includes assessing not only what medication to prescribe, but also at what dosage.

To see what current medications should be adjusted
If a patient is not getting the best results from their meds or is noticing serious side effects, he or she might request a PGx test to determine how to adjust their medications. This might include changing from one anti-depressant to another, altering the dose of a medication, or adding another medication.

Sometimes the patient might have drug-to-drug interactions that would otherwise be unknown to him or her and the physician.

To Reduce the Risk of an Adverse Reaction or Overdose
If a person is being considered for potentially dangerous treatment, they or the doctor might request a PGx test to insure that the patient does not suffer an Adverse Drug Reaction. This is an especially good idea if a patient is already taking multiple medications, or has had adverse reactions to medications in the past.

In the Case of an Emergency
Some people might want to test themselves or their children even if they are not on any medications or actively considering them. Knowing your ability to metabolize drugs, and having them in your medical record can be extremely helpful in the case of an unexpected emergency. If the person ends up in the hospital, providers can make timely prescribing decisions without the increased risk of using ineffective or unsafe options.

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Advanced Genetics Lab is our new molecular laboratory that just opened in Connecticut that can test patients within the United States. Our lab tests cover the metabolism of over 250 types of drugs, spanning cardiovasculars, psychotropics, pain meds, and many more.

• Our test takes about 30 seconds to perform by swabbing the inside of your cheeks and since your genes don't change, the results last your entire life.
• Patients with qualifying medical diagnosis may be covered by insurance
• We have trained pharmacists and scientists who review every report to help you and your doctor understand the report and make the best treatment decision.

If you are interested or have any questions, you can take a look at our website, or contact me directly:

Nicholas Gans
[email protected]

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Keep a look out for more pharmacogenetic content in the future!
As always, thanks so much for reading and please leave any questions or comments below!

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References

• Lazarou J, Pomeranz B, Corey PN. Incidence of adverse drug reactions in hospitalized patients: A meta-analysis of prospective studies. JAMA 1998;279:1200–1205.
• Narcotic Drugs 2014 (pdf). INTERNATIONAL NARCOTICS CONTROL BOARD. 2015. p. 21. ISBN 9789210481571. Archived (PDF) from the original on 2 June 2015.
• Talks, TEDx. “Personalized Prescriptions | Russ Altman | TEDxStanford.” YouTube, YouTube, 20 June 2013, www.youtube.com/watch?v=X1iKibDqtck.