by brant bullard | Mar 31, 2014 | News
Pharmacogenomics is the science of determining how genetic variability influences physiological responses to drugs, from absorption and metabolism to pharmacologic action and therapeutic effect. With increasing knowledge of the molecular basis for a drug’s action has come the recognition of the importance of an individual’s genetic makeup in influencing how he or she may respond to a drug.
Genetic variants in drug metabolizing enzymes can have a significant effect on the way a person responds to a drug. They can speed up or slow down enzymatic activity, or even inactivate an enzyme. In some patients, known as rapid metabolizers, drugs are metabolized too quickly. As a result, the average dose of the drug may be broken down too quickly to be effective, and a higher dose may be needed. Conversely, where the metabolite of the drug is active, as in the case of codeine (see below), rapid metabolism may lead to excessive accumulation of the active metabolite, which may result in toxic levels. In slow metabolizers, a drug administered at the recommended dose can accumulate due to such slow metabolism, potentially reaching toxic levels in the patient’s system and leading to adverse reactions. Such patients may require a smaller dose. In conjunction with other factors, pharmacogenomics offers the potential to enable doctors to identify the patients who are rapid or slow metabolizers of certain drugs and to adjust dosing accordingly to achieve both effective and safe treatment.
- Rapid metabolizers may break down a drug too quickly and require higher doses.
- Slow metabolizers may build up toxic levels of the drug and require smaller doses.
Clinical Applications of Pharmacogenomics
Warfarin (Coumadin and generics), an anticoagulant, is a recent example of the clinical use of pharmacogenomics to improve dosing. Warfarin has a narrow therapeutic window and a wide range of inter-individual variability in response, requiring careful clinical dose adjustment for each patient. Genetic variants in the warfarin target, the vitamin K epoxide reductase (VKORC1), as well as the warfarin metabolizing enzyme, cytochrome P450 2C9 (CYP2C9), influence the variation in patient response. Patients with certain variants of these genes eliminate warfarin more slowly and typically require lower warfarin doses. In those individuals, a traditional warfarin dose would more likely lead to an elevated International Normalized Ratio (INR), a longer time to achieve a stable warfarin dose, and a higher risk of serious bleeding events during the induction or dose-titration period of warfarin therapy. (FDA News)
Another recent example involves ultrarapid metabolizers of codeine, who have multiple copies of the gene for cytochrome P450 2D6 (CYP2D6), the enzyme that converts codeine into morphine, its active metabolite.
Tests to identify the three genetic polymorphisms for warfarin, codeine, and carbamazepine described above are commercially available.
Read more at FDA.com
For more information on the PGx Metabolic Validation Program, contact:
PGx Medical
Individualized Care – Personalized Medicine
info@pgxmed.com
405-509-5112
by brant bullard | Mar 26, 2014 | Metabolic Validation Program
At PGx Medical, our goal is to assist clients with our unique tools and programs to determine how to best incorporate and implement Pharmacogenetic testing within their clinic, company, pharmacy and center.
You like the program and you see the benefit of personalized medicine – but what does it cost?
Money and time is wasted on the “trial and error” process. And patient quality of life suffers in the interim. Poor metabolizers mean extra physician visits, laboratory and medication costs.
The PGx Metabolic Validation Program has demonstrated that 25%-40% of residents would be better served with a different medication based on Metabolic Validation. So the money saved by this “once in a lifetime test” is reason why many coverage types are reimbursing the cost.
While there isn’t a standard answer to the question of cost, what we do know is this program is definitely a cost saving long-term to both the patient and the provider. But more importantly, it improves the quality of life.
The PGx Metabolic Validation Program is currently implemented in hundreds of medical clinics and homes across the country. And our clients have confirmed…
- Helps reduce costs and improve care.
- Helps decrease the number of “unnecessary drugs” based on individual patient metabolic validation.
- And most importantly, helps deliver the most precise, personalized, validated level of therapy and care for each of the patients tested.
If you would like to learn more about how you can implement this cost saving program in your facility, or you would like more information on the program, contact us at:
PGx Medical
Individualized Care – Personalized Medicine
Info@pgxmed.com
www.pgxmed.com
405-509-5112
by brant bullard | Mar 24, 2014 | News
Studies have shown that approximately $300 billion is wasted each year on drugs that do not work in people who carry certain genes.
While some people never receive the full benefit from these drugs, others experience dangerous side effects.
In order to treat individuals who have had many failures with drugs, some doctors are turning towards personalized medicine – which provides a method by which doctors can customize medication regimens so that they are effective from the start.
What role does genetics have in pain?
Research shows that genetic factors account for a substantial proportion of all elements contributing to a patient’s response to drugs (others include age, sex, weight, general health and liver function).
Genes provide your body with instructions for making enzymes, which help break down drugs in your system, allowing your body to benefit from the medicine. Differences in your enzymes can affect how your body metabolizes a drug and how long the drug stays your body – and thus, how well drugs may work in an individual.
In particular, common pain medications require activation by an enzyme called CYP2D6 to become effective. Approximately half of patients have genes that alter the function of CYP2D6. Testing for these gene alterations allows for changes to dosage regimens in order to compensate for altered metabolisms – and optimizes the safety and efficacy of pain medications.
Without knowing an individual’s specific genetic code, physicians may often need to go through months of trial-and-error prescribing to find the right drug and dose. Physicians are often baffled when a drug will work for one person but not for another with the same diagnosis. The fact of the matter is that physicians really do not know how to predict drug effectiveness or toxicity because everyone is different. Genetic testing helps assess drug responsiveness. An individual’s genes can be a map that serves as a guide for physicians.
What is Pharmacogenetic Testing (PGT)?
A simple saliva test can evaluate an individual’s ability to metabolize or process drugs. Pain medications such as hydrocodone, oxycodone, diazepam and morphine utilize the CYP2D6 enzyme in order to metabolize the drug. As a drug gets metabolized, it is broken down into harmless pieces and eventually cleared. The activity of your clearance system is based on your genetic code. Once tested, this knowledge about an individual’s unique drug metabolizing system can help guide physicians.
What is the purpose of PGT?
Physicians would like to be able to anticipate how one may respond to a drug instead of relying on a trial-and-error process. By knowing the specific way one may break-down drugs, a physician can tailor treatment according to an individual’s unique metabolism and immediately find the right drug. Not only will this information help physicians predict which drug will best treat pain, a physician will also be able to predict the effective dose and potential for toxicity. In theory, this knowledge has the potential to save time, money and lives.
Pharmacogenetic testing (PGT), specifically, is exceedingly important for the proper management of pain because finding the precise drug and dose for each patient is so critically important. The groundbreaking development of PGT testing provides more individualized drug treatment for patients while also reducing adverse effects.
What if someone is an ultra-rapid metabolizer?
Ultra-rapid metabolizers break down medications really fast. Individuals who often receive medications that do not work or frequently need double doses of medication in order to relieve pain may be ultra-rapid metabolizers.
What if someone is a poor metabolizer?
Poor metabolizers tend to have severe side effects at low doses. Instead of going through one medication trial after another only to get sick every time, this test allows physicians to determine whether or not someone is a poor metabolizer, and act accordingly.
When is testing appropriate?
Undergoing genetic testing is a once in-a-lifetime experience because your genes do not change over time. Since many drugs are metabolized by one enzyme, you may only need one test. Once you are tested, you can keep your genetic test results for the rest of your life and share them with future care professionals. If one uses several medications (polypharmacy) and/or if several medications have failed to work properly, PGT may be appropriate to consider.
The Bottom Line:
Pharmacogenetic testing is now available with most physician pain specialists. The results of these genetic tests may help doctors: adjust the dose of medications more efficiently, prescribe medications that will work properly and give the patient the full benefit of the drug. It can also help people avoid medications that may be more likely to cause dangerous side effects and will often save money for patients in the long run. Drug responses don’t have to be a mystery now that treatments can be tailored to custom fit an individual’s specific genetic code.
By: Dr. Anita Gupta is an Award Winning Johns Hopkins Trained Anesthesiologist, Pain Specialist, Pharmacist & Editor. She currently is Associate Professor & Medical Director at Drexel University-College of Medicine in Philadelphia, PA. Read entire article at Foxnews.com
For more information on how you can implement Genetic Testing in your company, clinic, pharmacy or home, contact:
PGx Medical
Individualized Care – Personalized Medicine
Info@pgxmed.com
405-509-5112
by brant bullard | Mar 23, 2014 | News
In December 2008, the New York Times ran a story about a woman from California who had been taking a drug called tamoxifen to help prevent breast cancer. After two years of taking the drug, her doctor ordered a new genetic test that showed that her genes were preventing the drug from working properly.
“You find out you’ve been taking this medication for all this time, and find out you are not getting benefit…I was devastated” says the women. She had to stop taking tamoxifen. The good news is that she found out that the drug was not helping her and her doctor can now prescribe a drug which will work in her body. The bad news is that she could have known this two years ago if she had taken the genetic test from Day 1.
Experts report that approximately $300 billion is wasted each year on drugs which apparently do not work in people who have certain genes. These people never receive the full benefit from these drugs. Others are getting dangerous side effects.
For example, the blood-thinning drug warfarin is one of the top twenty drugs prescribed in the US. It is used to help prevent blood clots. If a person’s genes prevent the drug from working correctly, warfarin becomes dangerous. It is one of the top three drugs that cause hospitalization or emergency room visits. If a person has genes that allow too much warfarin to get into the bloodstream, the blood cannot clot correctly and the person can have bleeding. On the other hand, if a person has genes that prevent enough warfarin from getting into the bloodstream, the person could develop serious blood clots. The way a person’s body reacts to warfarin, tamoxifen and other drugs depends on differences in their genetic makeup.
Genes provide your body with instructions for making enzymes. Enzymes are needed for your body to break down drugs so your body can get benefit from the medicine. You carry two copies of every gene: one from your mother and one from your father. Differences in these genes can affect the speed of different enzymes you have in your body. This affects how well your body is able to use medicines and how well drugs work in your body. Differences in your enzymes can affect how your body can metabolize (break down) a drug and how long the drug stays your body. Based on what type of genes you carry, you may be:
- a poor drug metabolizer
If you are a “poor metabolizer”, you do not break down drugs well. This may result in too much drug in the body which may lead to a dangerous side effect or even death. In some cases, your body may not be able to break down certain drugs to their working form and therefore the drugs will not work properly.
- an extensive or “normal” drug metbolizer
You metabolize drugs at the normal rate.
- an ultra-rapid drug metabolizer
If you are an “ultra-rapid” metabolizer, this means you break down drugs too fast, causing them to be of no use in the body. If medications do not work properly, conditions such as high blood pressure, blood disorders, and cancer will be left untreated and may even lead to death.
Genetic Tests for Drug Response
Researchers have now found more than 30 types of drug metabolizing enzymes in humans and mostly all of them vary between people.
The three main genetic tests available today include: CYP2D6, CYP2C9, and CYP2C1.
Read entire article at: Consumer Health
For more information on Genetic Drug Testing
(PGx Metabolic Validation Program) contact:
PGx Medical
Individualized Care – Personalized Medicine
info@pgxmed.com
405-509-5112
by brant bullard | Mar 20, 2014 | News
Pharmacists may play a key role in applying pharmacogenetic discoveries to patient care.
Application of pharmacogenetic discoveries requires knowledge and understanding of the disposition and pharmacodynamics of drugs. Additionally, a good understanding of clinical factors that can influence pharmacokinetics and pharmacodynamics of drugs is also important in the effective application of pharmacogenetic discoveries to patient care.
Because pharmacists are experts in pharmacokinetics and pharmacodynamics, they can take a lead in application of pharmacogenetics in clinical practice. For example, NACB draft guidelines suggest that pharmacists may be engaged in interpreting pharmacogenetic testing results. In addition, some experts have suggested that pharmacists need access to patients’ genetic information in order to provide individualized pharmaceutical care before they fill prescriptions.
Although such involvement would require regulations and systems that secure and maintain patient confidentiality, the application of pharmacogenetics in clinical practice presents an opportunity where pharmacists can expand their roles in the genomic era. ~Medscape.com~
For more information, contact:
PGx Medical
Individualized Care – Personalized Medicine
info@pgxmed.com
405-509-5112
