How Genes Impact Medication Effectiveness
December 2, 2015
It has always been considered common sense that what works for one person does not always work the same way for someone else. Everyone is different. So it should not be a surprise that people and their prescription drug outcomes are not created equal.
Research has shown that our genes can impact a drug’s effectiveness and its potential side effects. Before DNA testing became widespread in forensics, and crime shows blanketed over primetime broadcast television, distinguishing bloodtypes was the most effective forensic tool. In the mid 20th Century, if a common blood type was found at a crime scene it would be little help to the investigation, but if a rare blood type was discovered the forensic science would be significant. DNA profiling has completely changed every aspect of forensic science. Genetic mapping and pharmacology are having a similarly ascendant moment in medicine. Everyday brings a new discovery and there is plenty of work remaining, but the importance of these advances are indisputable. Genetics will only prove to be more and more important in individual patient care.
Full genetic mapping for every patient is currently impractical and unaffordable. Even if doctors had every patient’s genome mapped, not all information is relevant when considering drug interactions and effectiveness. However there are certain genes and genetic expressions where current science has a depth of knowledge. In these areas, genetics and drugs have fostered gene-specific treatments, and further advancements will only broaden the understanding of genetic differences when prescribing medication. As the science and expense of genomic mapping improves, prescription drug outcomes guided by pharmacogenetics will improve and costs should be lowered across all areas.
Specific genes impact liver function, and different people have different outcomes with medications based on certain genetic predispositions. These variations in genetic expression are called polymorphisms. Many drugs are broken down by the liver and they can be separated into two categories: drugs that enter the body in an active or inactive form.
For drugs that are already in an active form — which means that the drug has immediate effect on the body — enzymes in the liver break the drug down to make it inactive, so the body can then discard it.
Genetic variations within liver metabolism can cause some patients to have decreased metabolism or increased metabolism of the drug, resulting in increased or decreased efficacy, and effecting variation in side effects or interactions with other drugs.
The other category of drugs enter our bodies in an inactive state as a pro-drug, and are activated when they are broken down in the liver. The liver enzymes that break the drug down are critical to making it work. For drugs that are converted into an active [form] in the liver, genetic variations can mean that a person needs to take a different kind of drug entirely.
In this scenario it has been discovered that some drugs are significantly more effective than others in reducing negative outcomes. The way the body absorbs a medication impacts not just the proper dose for optimal care, but the prescribed medication itself. Genetic information can lead to better outcomes and the applications are very real in many areas of pharmacological science.
Personalized medicine is a new frontier that is being explored to improve outcomes and it is an area of medicine that is only moving in one direction, forward. The more we know the better our care will be.
The public sector is invested in personalized and genomic medicine. President Obama’s 2015 State of the Union Address called for the launch of the Precision Medicine Initiative. Just recently the NIH announced it “has committed up to $72 million in preliminary funding opportunities for the [PMI] in 2016.”
With a public policy backing and a clear economic initiative, personalized medicine will be a major component of future health science. The medical and financial benefits will be hard to predict, but the impact will be enormous. With the rate of scientific discovery and advancement of big-data in every area of healthcare, it is easy to foresee genomic mapping improving the outcomes of medical treatment while reducing the costs once benefits are mainstreamed. The future may already be here, but it is far from being fully explored:
“Currently over 100 drugs have pharmacogenetic information in their product label from the Food and Drug Administration.”
It is easier to imagine a future where one hundred would seem like a small number of drugs with pharmacogenetic labels. Genetic data will soon become ubiquitous in every element of care. At the moment, genome mapping is not fast or cheap enough to enter into a routine doctor’s visit, but that is going to be different in the future. New genetic discoveries and market forces will increase efficiency and lower costs, hastening the advent of mainstream precision medicine. The combination of medical innovation with the focused power of big data pools and technological applications is going to change how we maintain health and treat illness. It is not too far into the future and the changes will be sweeping. The next decade is going to see a med-tech revolution that could rival the discovery of antibiotics. RxREVU is working towards the day when pharmacogenetics and digitally informed care delivery become a wide-spread reality, and not just the future we imagine.