Pharmacogenomics is the study of how variations in a person's entire genome can affect response to medications. It combines the science of drugs (pharmacology) with the study of genes (genomics).
Pharmacogenomics has the potential benefits of improving existing therapies in terms of both safety and efficacy, as well as informing discovery and development of new therapeutic agents.
Pharmacogenomics studies a person's entire genetic material to determine the response to medications. Pharmacogenetics is the study of how one gene can influence the response to medications.
There are many factors can that come into play regarding how a person can respond to a medication. This can include the person's age, sex, diet, environment, health status, past medical history, and genetic makeup.
A person's genes are used to create proteins that carry out all the various functions in the body. Differences in genes will lead to differences in how these functions happen. One such process is the breakdown of drugs with proteins called enzymes. How much activity these enzymes are performing affect how a person reacts to a drug. Due to differences in genetic makeup, some may have too much enzyme activity, leading to a drug being destroyed too quickly and losing their effect. Others may have too little enzyme activity, leading to the drug staying the body too long resulting in adverse drug reactions.
Adverse Drug Reactions (ADRs) are unwanted side effects of medications.
Over 2 million serious ADRs occur each year. ADRs cause over 100,000 deaths annually in the United States alone. This rate is much higher than deaths due to pulmonary diseases, diabetes, AIDS, pneumonia, and motor vehicle accidents. ADRs are also costly: approximately $136 billion can be attributed to ADRs in the United States alone annually, which is more than the costs of care for cardiovascular diseases and diabetes.
Pharmacogenomics allows the ability to customize a drug regimen for a specific patient. Drug dosages can be modified to provide the most effective amount of drug for a patient and/or to minimize the probability of experiencing side effects, as well as considering safer alternatives to standard treatment. One example is taking a drug to reduce blood sugar levels. Based on a person's genes, they may be susceptible to side effects such as an upset stomach, which could lead to the patient avoiding the medication. With pharmacogenomics, the prescriber would know in advance to consider an alternative medication for the patient to avoid complications, or alter the dosage of the medication to be prescribed.
Personalized medicine (also known as precision, individualized, or tailored medicine) is a model of customizing a patient's drug regimen based on his or her individual characteristics. This gives the ability to classify a patient into subpopulations that differ in susceptibility to a particular disease, or a response to specific treatment.
Traditionally, a "one size fits all" approach was used to treat all patients with a certain diagnosis. This did not take into account the variability of a patient's traits that could lead to a difference in response to treatment or adverse drug reactions. With personalized medicine, a treatment strategy can be devised specific for patients based on their genetic profile.
This approach holds to the idea that a standard type of dose and regimen can be applied to a general population. It does not take into account variations in populations that can affect responses to drugs.
Because of variations in a population's genetic makeup, there are variations in response to medications. 50% of people taking medications for diabetes do not get the appropriate efficacy. Only 25% of people taking medications for cancer get an adequate response.
Out of the 1200 FDA-approved medications, around 180 drugs possess pharmacogenomic information on their drug label. 84 out of those 1200 drugs are affected by "actionable" pharmagenomics.
Out of the 4 billion prescriptions in the US alone, 720 million of them are for pharmacogenomic high risk medications; that's about 18% of all the prescriptions written in the US. (about 1 in 5 prescriptions written in the USA.)
It can save not only money, but time as well. The ability to predict what drugs may be ineffective or produce side effects can guide prescribers to alternative medications or adjustments to their current medications. This leads to the potential of avoiding prescribing additional medications to treat side effects of other medications, as well as being able to treat conditions in a timely manner.
Yes. By gathering information about a population's genetic material, drugs can be developed to target specific populations that share a common trait. A major purpose of using pharmacogenomics is use genetic information to help develop drugs that produce the most effectiveness and the least amount of side effects.
Actionable genes are genes that can be analyzed to drive drug therapy; that is, if a variant of these genes is detected, actions can be taken to modify a patient's regimen to improve a patient's outcome.
Pharmacogenomics can help individualize drug therapy to account for genetic variations to optimize efficacy and safety.
Some resources to learn more about pharmacogenomics can be found at the following websites:
https://www.nigms.nih.gov/education/Pages/factsheet-pharmacogenomics.aspx
http://pharmgkb.com/
http://www.nature.com/scitable/topicpage/pharmacogenomics-and-personalized-medicine-643
https://www.genome.gov/27530645
Typically, a saliva sample is collected for testing. Other samples can be buccal swabs or blood samples.
Yes. The FDA currently list over 100 medications with pharmacogenetic implications.
One example is Plavix, a blood thinner. People possessing variants of CYP2C19 gene can cause difference in its effectiveness. Another example is simvastatin and SLCO1B1 gene. Others include citalopram (Celexa), escitalopram (Lexapro), warfarin (Coumadin), codeine, fluxoetine (Prozac), tramadol (Ultram), and more.
The necessity of pharmagogenetic testing is on an individual basis. This can depend on your history, what medications you are currently taking, and other factors. Patients who do not respond to drug therapy, or have a family history of medications with unusual side effects, or patients wishing to take a proactive approach to medication therapy should consider testing.
Genes are inherited and as such it may be beneficial for patients to recommend pharmacogenomic testing to family members especially when inefficacy or side effectsrun in a family. Additionally, patients can recommend testing to family members taking medications with pharmacogenetic implications.
Patients are encouraged to share information from a pharmacogenomics test with their health care providers. The results themselves are confidential and will not be released unless consent is given.
Usually, it is not necessary to be tested multiple times for a certain gene, as your genetic make up does not change. Additional tests may be performed when adding a new drug that is associated with a different actional pharmacogene.
Testing alone will not determine how a patient will respond to a drug. It is used as a factor for determine what would be the best course of action for drug therapy. In addition, not every drug has testing available.