Pharmacogenetics is the study of how each person’s unique genetic makeup affects their response to medication. Sometimes covered by insurance, pharmacogenetic testing analyzes a genetic sample to determine medication’s potential for overall success. While diet, health, and environment all play a part in medication response, there is no stronger indication than genetics.
What Is Pharmacogenetic Testing?
Pharmacogenetics hopes to remove the guesswork from the process of prescribing and taking medications. Testing is not available for all medications and there is not a single test that can measure all medication effectiveness, but many physical health and mental health medications can be better understood with pharmacogenetics.
According to Dr. Ron Albucher, advisor for Prairie Health, “Just like the way a difference in one gene can lead one person to have freckles while another person has none, different genetic variations lead to different forms of the same enzyme. Different enzyme variations process the same drug in different ways.
Pharmacogenetic tests can give doctors insight into how their patients might process certain medications and allow them to customize prescriptions as a result. For example, results might show that one person has a type of enzyme that breaks down a medication very quickly. This means that this medication at its standard dosage might not stick around in the body long enough to work. As a result, the doctor might increase the dosage they give to their patient.”
It aims to understand how each person’s DNA influences their response to a medication or a group of medications. Ideally, pharmacogenetic testing can predict which drug will most likely produce the desired result, as well as what will create unwanted side effects; this way, prescribers have more information to recommend an effective treatment plan.
People exploring new medications and prescriptions drugs recommended by their mental health providers face a challenging journey of uncertainty. At best, these medicines work to produce the wanted changes, but at worst, starting a new medication or increasing the dose of an established drug can trigger dangerous and deadly reactions and side effects.
Here are some stats on drug reactions. Each year:1
- People experience two million adverse drug reactions
- One million emergency room visits are required due to adverse drug reactions
- About 100,000 people die due to drug reactions
Pharmacogenetic testing attempts to establish safety and confidence when prescribing and trying medications.
Pharmacogenetic tests are used to:2,3
- Learn if a medication can be effective for someone
- Target the best dosage of a medication
- Accurately predict how serious side effects may emerge from the drug
- Determine how quickly the body might process the medication
Pharmacogenetic testing is based on the notion that we can use an individual’s DNA to predict and explain the possible reactions to medications. DNA influences multiple aspects of how one will respond to a new medication.
Impacts of DNA
The impacts of DNA include:4
- Drug receptors: Medications need to attach to cell receptors to be effective, and DNA controls what kind and how many receptors are available. People with fewer receptors will need higher doses of a medication to see benefit.
- Drug uptake: Drug uptake involves the rate and efficiency that a medication is absorbed into the body. If the uptake is too slow, the medication will not produce the desired results and could build up in other parts of the body, leading to an increased risk of harmful side effects.
- Drug breakdown: Breakdown of a drug is necessary as it processes and leaves the body. High breakdown rates require more of a medication, while low breakdown could indicate lower dosages.
How Does Pharmacogenetics Work In Psychiatry?
In psychiatry, pharmacogenetics give the prescriber and patient more information about the best medication and dosage without the need for multiple trials. Pharmacogenetic testing could result in fewer side effects and quicker symptom relief.
When a person presents to a psychiatrist, primary care doctor (PCP), or nurse practitioner to receive treatment for their mental health concerns, the prescriber can utilize numerous medications to address symptoms. Even for common conditions, like anxiety and depression, a prescriber may be forced to choose between more than a dozen medications without a great understanding of how effectively they will work. Additionally, different people process medications differently, so ten people could take the same dose of the same medication and have different outcomes.2,5
How Do Providers Utilize Pharmacogenetic Testing?
Providers may utilize pharmacogenetic testing preventatively or reactively. Some opt to require patients to complete testing prior to treatment, while others recommend it after several unsuccessful medication trials. Results might show a type of enzyme that breaks down a medication quickly, meaning that, at its standard dosage, the medication might not remain in the body long enough to work. As such, the provider might increase the dosage.
Who Should Get Pharmacogenetic Testing?
People who have not found the desired success with previous medications should consider pharmacogenetic testing. It can give doctors insight intowhy they have not responded well in the past, and show them how to avoid repeat situations in the future. By identifying which medications might be ineffective at a standard dose or cause adverse reactions, the doctor can prescribe more effectively.
In some situations, people may be so irritated by ongoing issues that they consider giving up on using any medications in the future. For these people, a round of pharmacogenetic testing could offer new hope and direction for medication treatment.
Ethnic and racial minorities, as well as women, should also practice more active curiosity about testing options. Prior to the 1993 NIH Revitalization Act, pharmaceutical companies weren’t obligated to include people assigned female at birth or people of color in their trials. Many drugs in use today were initially developed or tested before 1993, and as a result, the prescription guidelines that were created then and exist today cater to white men.6
Dr. Albucher states, “Scientists know that some genetic variations occur more (or less) frequently in white males than in other demographics. Therefore, if you’re not a cisgender white male, pharmacogenetic testing can help your doctor create a medication regimen that is more customized to you.”
Who Provides Pharmacogenetic Testing?
Pharmacogenetic testing is a relatively new procedure, so the process is not universal. Generally, a doctor or other practitioner writes a prescription for the testing as they would any other laboratory work up. The individual then presents to a lab location where they provide a sample of saliva, blood, or buccal tissue from a mouth swab, though blood is the preferred method.1
Once the sample is gathered, it is sent to specific labs across the country for analysis. Due to the precision needed in the testing, the turnaround time for labs could be 14 days or longer.1 Once results are completed, the laboratory will send results to the prescriber or to an electronic database where the individual can review their record.
What Do the Results of a Pharmacogenetic Test Mean?
Pharmacogenetic test results will not always provide a clear and definitive path for people interested in modifying their medication treatment; however, it can show how quickly and effectively a person will process a medication. For many, this information will greatly influence their medication decisions.3
Tests also indicate whether a certain medication is likely to cause adverse side effects for the individual and identify patients who are rapid—or slow—metabolizers. With this, doctors know what to eliminate from their set of options and can quickly settle on better options at more effective doses.
Once the individual and prescriber gain access to the testing results, they can enter into a conversation about medication with more data than they had previously. It is valuable to view pharmacogenetic testing as a useful guide, rather than a certain path.3
New data paired with earlier information gained from medication trials can significantly direct the next step in treatment. In other situations, the findings could offer no more information, so the treatment team will continue using some degree of guesswork in determining medications.
What Are the Limits of Pharmacogenetic Testing?
As pharmacogenetic testing matures, it will likely yield more helpful and detailed information, but for now, the limitations are significant. Anyone interested in testing options should have an honest and open conversation with their treatment team to explore the potential risks and benefits of the procedure.
Many limitations are linked to the newness of the procedure. The current state of testing cannot fully determine the best treatment for all people; fortunately, the only risk comes when an individual or a prescriber assigns too much weight to the results. Despite its potential, pharmacogenetic testing doesn’t have all of the answers.
Dr. Albucher says, “Because pharmacogenetic tests look at a very specific set of genes related to treatment, they aren’t useful for answering other commonly asked questions about family history or likelihood of developing a certain disease. They are more likely to tell someone how their enzymes work and how they might respond to medications.”
Another limitation of pharmacogenetic testing is the validity for children and adolescents. In recent years, more families and pediatricians have been exploring pharmacogenomics to assist their children and patients dealing with concerns like depression and anxiety and to avoid potentially harmful side effects of some medications.7 That said, most pharmacogenetic testing is based on information from adults. For this reason, groups like the American Academy of Child and Adolescent Psychiatry say that it should not be used with children to select medications.7
How Much Does Pharmacogenetic Testing Cost?
Finding the exact cost of pharmacogenetic testing can be complicated with wide variation depending on insurance coverage, specific testing policies, and location. Some reports say that many cost $300 or more when paying out of pocket. Because the field of pharmacogenetics is relatively new, not all doctors will recommend testing to their patients. People who do end up pursuing genetic testing often end up paying for it through their insurance companies (if their plan covers it) or out-of-pocket.
The testing cost may seem high, but if the process can help people save time, lower symptoms, and avoid missed time and lower performance at work, it could more than pay for itself. Also, copays for unhelpful medications and trips to the psychiatrist can quickly add up, which further reduces the overall cost of pharmacogenetic tests.
Does Insurance Cover Pharmacogenetic Testing?
Whether insurance covers the price of a genetic test depends on the insurer and the plan. For example, Medicare and UnitedHealth specifically cover some pharmacogenetic tests. Another major healthcare insurer, Aetna, covers several pharmacogenetic and pharmacodynamic testing options, but these services will likely encounter increased scrutiny when it comes to payment.1
Anyone interested in such testing should contact their prescriber, the lab, and the insurance company to gather information before making the decision to undergo testing.
Companies may have extra criteria needed for testing due to its expense. They could require people to have multiple failed medication trails or a history of adverse side effects before agreeing to pay for such services.
Final Thoughts On Pharmacogenetics
Anyone struggling with intense, debilitating, or concerning mental health symptoms wants a medication to quickly and effectively alleviate their concerns; but often, starting a medication can be frustrating and fruitless. If you are planning to start a medication or change your current regimen, you may want to talk to your prescriber about pharmacogenetic testing.
